The document experimentally investigates conditions for producing high concentrations of hypochlorous acid water without a barrier membrane between electrode plates. It examines factors like electrode plate interval, flow rate of sodium chloride solution, sodium chloride concentration, and current density. The concentration of available chlorine is measured using a residual chlorine meter. Results show that current density and sodium chloride concentration strongly affect the high concentration production of available chlorine. These results can help produce chlorinated water called hypochlorous acid water.
Experimental Investigation on Hypochlorous Acid Water Production using Electr...iosrjce
Available chlorine has an effect on the sterilization and disinfection of a water supply, especially for
drinking water. In order to obtain available chlorine industrially, it is important to generate available chlorine
at high-concentrations with high-efficiency. However, it is difficult to simultaneously attain high concentration
with high-efficiency. In this paper, the optimum operation conditions for available chlorine production are
proposed from the standpoint of high-efficiency. The experiment was conducted using a flow-type reactor with
narrow and parallel electrode plates, even though it lacks a barrier membrane between the plates. The
governing factors are: the electrode plate interval and the flow rate of sodium chloride solution from the
viewpoint of hydrodynamics, and the concentration of sodium chloride of the medium and current density
supplied to the electrode plates from the standpoint of chemical reactions. The production efficiency of the
available chlorine was estimated by the ratio of actually reacted available chlorine to the ideally reacted
available chlorine. The governing factors were examined based on the experimental results. As a result, the
production of available chlorine with high-efficiency is strongly affected by the flow rate as well as the current
density. These results will be useful for producing chlorinated water, called hypochlorous acid water.
Factors affecting Gold Recovery from Secondary Ore_TatendaTatenda Chingosho
The document discusses factors that affect the recovery of gold from low-grade secondary ore using hydrometallurgical processes. It finds that gold recovery is highly dependent on cyanide concentration, leaching time, and pH level. The highest recoveries were obtained at a cyanide concentration of 0.056M, a pH of 11, and a leaching time of 48 hours. Particle size analysis showed that most of the gold was contained in finer particles. Varying these process parameters can optimize gold recovery from low-grade secondary ores.
This document discusses wet air oxidation as a process for treating concentrated chemical waste streams. It begins with an overview of chemical process industry and various waste treatment approaches. Wet air oxidation is described as a subcritical thermal oxidation process that occurs in an aqueous medium between 100-250°C and 5-20 atm of oxygen pressure. Key advantages are its ability to handle concentrated and toxic wastes while allowing for water recycling. The document outlines reaction mechanisms, kinetics, catalyst use and integration with other processes. Design considerations and a systematic approach for implementing water treatment and recycling are also presented.
This research article studied the effect of pH on the properties of aqueous colloidal dispersions of graphene oxide (GO) and chemically converted graphene (CCG). GO was prepared using a modified Hummer's method and CCG was prepared by chemical reduction of GO. The particle size, zeta potential, and light absorption of GO and CCG colloids were analyzed as a function of pH achieved by titration with HCl or NaOH. The GO colloid was stable between pH 4-11, while the CCG colloid was stable in the narrower range of pH 7-10. Both colloids exhibited average particle sizes of ~1 micron at low pH and 300-500 nm at higher pH
This document summarizes a study that examined the impact of water chemistry on the dissolution of lead carbonate in drinking water distribution systems. Specifically, it investigated the effects of pH (7.0-9.5), temperature (5°C vs 20°C), and alkalinity (moderate vs low) on the dissolution of hydrocerussite and cerussite in batch experiments. The results showed that pH did not significantly impact dissolution from 7.0-9.5. Cold temperature (5°C) and moderate alkalinity decreased the solubility of lead species, which was unexpected. The purpose was to better understand how water chemistry affects the stability of lead corrosion scales and the release of lead into drinking water.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
The document summarizes a study on the simultaneous extraction of copper and iron from chalcopyrite concentrates in hydrochloric acid media using chlorine gas. The study investigated the effect of various parameters including acid concentration, temperature, sodium chloride addition, and time on the dissolution of copper and iron. Key findings include that copper and iron dissolution increased with acid concentration and temperature but decreased with the addition of sodium chloride. Dissolution was also found to increase over time. The best conditions for copper extraction were determined to be 333K temperature, 10% concentrate, and 1 hour leaching time.
This document describes a study that evaluated the use of a gas-liquid membrane contactor process for selective removal of hydrogen sulfide (H2S) from biogas. The effects of biogas retention time (GRT), membrane thickness, and liquid absorbent pH were investigated. The results showed that H2S removal efficiency improved with increasing GRT and absorbent pH, and decreased with increasing membrane thickness. Lower GRT and thicker membranes resulted in higher desulfurization selectivity. The methane content of the treated biogas increased with GRT and the process achieved high H2S removal without significant methane loss. SEM-EDS analysis found inorganic deposits on the membrane surface but no membrane clogging or fouling issues. Overall,
Experimental Investigation on Hypochlorous Acid Water Production using Electr...iosrjce
Available chlorine has an effect on the sterilization and disinfection of a water supply, especially for
drinking water. In order to obtain available chlorine industrially, it is important to generate available chlorine
at high-concentrations with high-efficiency. However, it is difficult to simultaneously attain high concentration
with high-efficiency. In this paper, the optimum operation conditions for available chlorine production are
proposed from the standpoint of high-efficiency. The experiment was conducted using a flow-type reactor with
narrow and parallel electrode plates, even though it lacks a barrier membrane between the plates. The
governing factors are: the electrode plate interval and the flow rate of sodium chloride solution from the
viewpoint of hydrodynamics, and the concentration of sodium chloride of the medium and current density
supplied to the electrode plates from the standpoint of chemical reactions. The production efficiency of the
available chlorine was estimated by the ratio of actually reacted available chlorine to the ideally reacted
available chlorine. The governing factors were examined based on the experimental results. As a result, the
production of available chlorine with high-efficiency is strongly affected by the flow rate as well as the current
density. These results will be useful for producing chlorinated water, called hypochlorous acid water.
Factors affecting Gold Recovery from Secondary Ore_TatendaTatenda Chingosho
The document discusses factors that affect the recovery of gold from low-grade secondary ore using hydrometallurgical processes. It finds that gold recovery is highly dependent on cyanide concentration, leaching time, and pH level. The highest recoveries were obtained at a cyanide concentration of 0.056M, a pH of 11, and a leaching time of 48 hours. Particle size analysis showed that most of the gold was contained in finer particles. Varying these process parameters can optimize gold recovery from low-grade secondary ores.
This document discusses wet air oxidation as a process for treating concentrated chemical waste streams. It begins with an overview of chemical process industry and various waste treatment approaches. Wet air oxidation is described as a subcritical thermal oxidation process that occurs in an aqueous medium between 100-250°C and 5-20 atm of oxygen pressure. Key advantages are its ability to handle concentrated and toxic wastes while allowing for water recycling. The document outlines reaction mechanisms, kinetics, catalyst use and integration with other processes. Design considerations and a systematic approach for implementing water treatment and recycling are also presented.
This research article studied the effect of pH on the properties of aqueous colloidal dispersions of graphene oxide (GO) and chemically converted graphene (CCG). GO was prepared using a modified Hummer's method and CCG was prepared by chemical reduction of GO. The particle size, zeta potential, and light absorption of GO and CCG colloids were analyzed as a function of pH achieved by titration with HCl or NaOH. The GO colloid was stable between pH 4-11, while the CCG colloid was stable in the narrower range of pH 7-10. Both colloids exhibited average particle sizes of ~1 micron at low pH and 300-500 nm at higher pH
This document summarizes a study that examined the impact of water chemistry on the dissolution of lead carbonate in drinking water distribution systems. Specifically, it investigated the effects of pH (7.0-9.5), temperature (5°C vs 20°C), and alkalinity (moderate vs low) on the dissolution of hydrocerussite and cerussite in batch experiments. The results showed that pH did not significantly impact dissolution from 7.0-9.5. Cold temperature (5°C) and moderate alkalinity decreased the solubility of lead species, which was unexpected. The purpose was to better understand how water chemistry affects the stability of lead corrosion scales and the release of lead into drinking water.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
The document summarizes a study on the simultaneous extraction of copper and iron from chalcopyrite concentrates in hydrochloric acid media using chlorine gas. The study investigated the effect of various parameters including acid concentration, temperature, sodium chloride addition, and time on the dissolution of copper and iron. Key findings include that copper and iron dissolution increased with acid concentration and temperature but decreased with the addition of sodium chloride. Dissolution was also found to increase over time. The best conditions for copper extraction were determined to be 333K temperature, 10% concentrate, and 1 hour leaching time.
This document describes a study that evaluated the use of a gas-liquid membrane contactor process for selective removal of hydrogen sulfide (H2S) from biogas. The effects of biogas retention time (GRT), membrane thickness, and liquid absorbent pH were investigated. The results showed that H2S removal efficiency improved with increasing GRT and absorbent pH, and decreased with increasing membrane thickness. Lower GRT and thicker membranes resulted in higher desulfurization selectivity. The methane content of the treated biogas increased with GRT and the process achieved high H2S removal without significant methane loss. SEM-EDS analysis found inorganic deposits on the membrane surface but no membrane clogging or fouling issues. Overall,
The document discusses the processes of mixing, coagulation, and flocculation in water treatment. It defines coagulation as destabilizing particles in water so they can attach to other particles and be removed. Flocculation is the formation of larger particles called flocs. Key factors that affect these processes are mixing conditions, pH, alkalinity, temperature, and turbidity. Common coagulant chemicals like alum and ferric salts are added for coagulation. Flocculation aids like polymers can help form stronger flocs. Proper process control includes monitoring these factors. Rapid mixing distributes coagulants uniformly while flocculation encourages floc formation.
This study investigated using a bio-electrochemical system (BES) for the simultaneous removal of nitrate and sulfide from different sources without mixing the sources. The anode chamber of the BES was fed with effluent from a sulfate reducing reactor as an electron donor source, while the cathode chamber was fed with nitrate-rich groundwater as an electron acceptor source. The BES was effective at simultaneously removing 10 gS/m3/d of sulfide and 7.26 gN/m3/d of nitrate without mixing the sources. Denitrification in the cathode chamber was supported by electrons from sulfide oxidation in the anode chamber passing through the membrane, and possibly from corrosion of
This document describes a study that evaluated a hybrid membrane bioreactor process for removing hydrogen sulfide (H2S) from biogas. The process used a polydimethylsiloxane membrane to first absorb H2S from biogas into an alkaline liquid, followed by biological oxidation of H2S in the liquid. The effects of absorption liquid pH, biogas flowrate, and dissolved oxygen concentration on H2S removal efficiency and selectivity were investigated. The results showed that pH 7 performed better than pH 8.5, and H2S removal exceeded 97% at flowrates below 148 g H2S/m3d and dissolved oxygen below 1 mg/L. This novel hybrid process provides an effective and low-cost
This document summarizes a study that evaluated using an autotrophic denitrification process to remove hydrogen sulfide (H2S) from biogas produced by anaerobic digestion of chicken manure. A laboratory upflow fixed bed reactor was fed scrubbed H2S from the biogas and nitrate. Over 95% H2S and 90% nitrate removal were achieved. When fed directly scrubbed H2S, the reactor experienced clogging from elemental sulfur particles. Feeding scrubbed H2S from biogas at pH 8-9 achieved 98% H2S and 97% nitrate removal without clogging. This process biologically converted H2S to elemental sulfur while denitrifying wastewater.
1. The document describes a study on removing NOx from gas by pre-oxidizing NO with ozone and absorbing the oxidation products in alkaline aqueous solutions.
2. Experiments were conducted in a laboratory apparatus to determine the absorption performance of NO oxidation products in solutions of NaOH, KOH, Ca(OH)2, CaCO3, and water. The effect of initial NO concentration and NaOH concentration on NOx removal effectiveness was also examined.
3. Results showed that ozone is effective at oxidizing NO to NO2 in the gas phase. Absorption of oxidation products, particularly in NaOH solutions, allowed high levels of NOx removal to be achieved.
This document summarizes research on catalytic wet air oxidation (CWAO) as an alternative wastewater treatment technique to wet air oxidation (WAO). CWAO uses catalysts to allow for milder operating conditions and shorter reaction times. Experimental results showed that over 50% reduction in chemical oxygen demand (COD) could be achieved in about an hour at temperatures over 200°C and pressures above 30bar using heterogeneous catalysts like palladium on titanium dioxide. The research tested CWAO on various wastewaters and found the most effective catalysts were mixed metal oxide coatings on titanium meshes and ruthenium oxide on titanium dioxide, which constantly decreased COD levels.
This document describes a procedure for determining the chemical oxygen demand (COD) of water samples. COD is a measure of the amount of oxygen required to chemically oxidize organic matter in water. The procedure involves incubating a water sample with potassium dichromate and sulfuric acid, then titrating the excess dichromate with ferrous ammonium sulfate solution. The COD value is calculated based on the volume of ferrous ammonium sulfate used in the titration. The document provides details on the chemicals, apparatus, procedure, sample readings, and calculations for determining COD and interpreting the results.
This document discusses cooling water treatment at a fertilizer plant in India. It provides details on the plant's cooling towers and water chemistry parameters. Cooling water treatment is needed to prevent corrosion, scaling, and microbial fouling of the system. Common issues like corrosion, scaling, and biofouling are discussed along with the mechanisms of corrosion inhibition, scale inhibition, and microbial control through chemical treatment.
This document discusses cooling water analysis and treatment. It covers topics like pH adjustment using sulfuric acid to control scaling, the effects of high pH like increased microbial growth, how much acid is required, chlorine dosing to lower pH and kill bacteria, chlorine demand, factors affecting corrosion like chlorides and stress corrosion cracking of stainless steel, and corrosion inhibition using phosphates. Maintaining the proper delta phosphate is important to control corrosion.
This document provides instructions for measuring chemical oxygen demand (COD) using the dichromate reactor digestion method. Key points include:
- The test measures COD concentrations from 0.7-40 mg/L (ULR range), 3-150 mg/L (LR range), 20-1500 mg/L (HR range), and 200-15,000 mg/L (HR Plus range).
- Samples are digested using COD reagent vials in a heated reactor to oxidize organic compounds. Absorbance of digested samples is then measured colorimetrically.
- Interferences from chloride are removed by mercuric sulfate in the reagent vials. Samples with high chloride must
The chlor-alkali process is an industrial process that uses electrolysis to produce chlorine, sodium hydroxide, and hydrogen from salt water. It involves passing an electric current through a brine solution to drive the following reaction: 2NaCl + 2H2O → 2NaOH + Cl2 + H2. The process was first developed in the 1850s but improved in the 1890s with the mercury cell. Today, membrane and diaphragm cells are more commonly used, accounting for 60% and 14% of European production respectively. The main uses of the products are in polymers, pesticides, antiseptics, acid production, metallurgy, and the paper industry.
Water supply and sewerage engineering laboratoryTaufique Hasan
The document discusses water quality testing performed on samples from the First Ladies Hall of Shahjalal University of Science and Technology, Sylhet. Water samples were tested for various parameters under water supply engineering (drinking water) and sewerage engineering (sewage). For drinking water, tests found the pH, carbon dioxide, turbidity, alkalinity, iron, and manganese levels were all within acceptable limits for drinking water. For sewage, tests were conducted to determine total solids, biochemical oxygen demand, chemical oxygen demand, and chloride. The hardness of the water sample was also found to be within acceptable limits.
Elemental composition study of leachate in some dumpsites in bauchi metropolisAlexander Decker
The document analyzes samples of leachate from four dumpsites in Bauchi, Nigeria to determine concentrations of heavy metals. Complexometric titration methods were used to measure levels of cadmium, chromium, lead and copper. The results found mean concentrations of cadmium ranged from 0.08-0.22 mg/dm3, chromium ranged from 0.01-0.10 mg/dm3, lead ranged from 1.81-2.60 mg/dm3, and copper ranged from 1.11-1.99 mg/dm3. These levels indicate low amounts of heavy metals in the leachates, though their presence still suggests contamination from the dumpsites.
HRSG water chemistry & corrosion controlAbdul Hannan
This document discusses water chemistry and corrosion control in HRSGs. It describes the components of HRSGs, including economizers, steam drums, evaporators, and superheaters. It outlines treatment methods for different sections of the HRSG to control corrosion and deposition, including phosphate and volatile amine treatments. It also discusses common corrosion mechanisms like pitting, crevice, and stress corrosion cracking that can occur in HRSGs and outlines best practices to minimize corrosion.
Nitric acid is a strong acid that is colorless as a pure liquid but commercial samples may appear yellowish. It is highly corrosive and a strong oxidizer. Nitric acid is produced industrially via the Ostwald process, which involves ammonia oxidation over a platinum catalyst in three steps: primary oxidation to nitric oxide, secondary oxidation to nitrogen dioxide, and absorption of nitrogen dioxide in water to form nitric acid. Nitric acid has many industrial and laboratory uses including fertilizer and explosive production.
This document summarizes a study on using electrocoagulation to remove tartrazine dye from simulated wastewater. Tartrazine dye is commonly used in foods, drugs, and textiles but is hazardous. The study investigated the effect of parameters like electrolysis time, dye concentration, pH, and potential on decolorization efficiency. Iron and steel electrodes were used in an electrolytic cell with NaCl electrolyte to treat wastewater samples. Results showed that absorbance decreased with increased time, and maximum removal capacity was achieved. pH was also affected by concentration and time. However, potential changes did not significantly impact absorbance. Overall, electrocoagulation was found to be an effective process for removing the azo dye
The document discusses the use of phosphates in power plant chemistry. It describes phosphate treatment which uses various forms of phosphates like trisodium phosphate to prevent scale and corrosion in boilers. It outlines the reactions that occur during phosphate treatment and highlights hazards like irritation from inhalation or skin contact with phosphates. The document provides guidance on handling, storage, personal protective equipment and first aid measures for phosphates.
This document summarizes a research paper that proposes a FACTS-based Static Switched Filter Compensator (SSFC) scheme for improving power quality when integrating wind energy into smart grids. The SSFC scheme uses controlled switching between two capacitor banks to provide series and shunt compensation. It is controlled using a tri-loop dynamic error controller and VSC controller to mitigate harmonics, stabilize voltages, improve power factor, and reduce losses. Simulation results using Matlab/Simulink show the SSFC scheme improves voltage regulation, reduces current and voltage harmonics to within IEEE limits, and enhances the power factor at generator, load and grid buses compared to without SSFC.
This document summarizes a study that analyzed the chemical composition of wastewater generated from olive oil production and evaluated its potential use as fertilizer on agricultural land. The study found that the wastewater was acidic but rich in organic matter and nutrients like potassium. Soil analysis before and after application of the wastewater showed increases in organic matter and nutrients. Over 280 days, biochemical and chemical oxygen demand of the wastewater decreased by around 50%, indicating its characteristics were modifying. The high potassium and organic content suggests the wastewater could improve soil quality and be a lower-cost fertilizer, though long term effects require more research.
This document summarizes an artificially intelligent investment risk calculation system based on distributed data mining. The system uses a web-based platform to provide registered users investment recommendations and risk assessments based on their financial transaction history. It analyzes data from financial sectors to guide users on investment decisions. It also models an internal bank loan process, tracking employee credibility and targets to distribute profits/losses. The system was developed using HTML, CSS, JavaScript, MySQL, and JSP. It stores user and transaction data in relational databases to power its artificial intelligence algorithms for investment suggestions and risk calculations.
This document summarizes a research paper on developing a reconfigurable hardware architecture for implementing maximum likelihood (ML) decoding algorithms in MIMO systems. It begins by introducing MIMO techniques for improving wireless communication throughput. It then describes various MIMO receiver algorithms and chooses ML for its best performance. The document outlines the ML decoding algorithm and presents a Simulink model. It discusses implementing the MIMO decoder as a modular, reconfigurable architecture on an FPGA and shows placement results on a Xilinx Virtex 4 chip. The work aims to provide flexible hardware for MIMO signal processing applications.
The document discusses the processes of mixing, coagulation, and flocculation in water treatment. It defines coagulation as destabilizing particles in water so they can attach to other particles and be removed. Flocculation is the formation of larger particles called flocs. Key factors that affect these processes are mixing conditions, pH, alkalinity, temperature, and turbidity. Common coagulant chemicals like alum and ferric salts are added for coagulation. Flocculation aids like polymers can help form stronger flocs. Proper process control includes monitoring these factors. Rapid mixing distributes coagulants uniformly while flocculation encourages floc formation.
This study investigated using a bio-electrochemical system (BES) for the simultaneous removal of nitrate and sulfide from different sources without mixing the sources. The anode chamber of the BES was fed with effluent from a sulfate reducing reactor as an electron donor source, while the cathode chamber was fed with nitrate-rich groundwater as an electron acceptor source. The BES was effective at simultaneously removing 10 gS/m3/d of sulfide and 7.26 gN/m3/d of nitrate without mixing the sources. Denitrification in the cathode chamber was supported by electrons from sulfide oxidation in the anode chamber passing through the membrane, and possibly from corrosion of
This document describes a study that evaluated a hybrid membrane bioreactor process for removing hydrogen sulfide (H2S) from biogas. The process used a polydimethylsiloxane membrane to first absorb H2S from biogas into an alkaline liquid, followed by biological oxidation of H2S in the liquid. The effects of absorption liquid pH, biogas flowrate, and dissolved oxygen concentration on H2S removal efficiency and selectivity were investigated. The results showed that pH 7 performed better than pH 8.5, and H2S removal exceeded 97% at flowrates below 148 g H2S/m3d and dissolved oxygen below 1 mg/L. This novel hybrid process provides an effective and low-cost
This document summarizes a study that evaluated using an autotrophic denitrification process to remove hydrogen sulfide (H2S) from biogas produced by anaerobic digestion of chicken manure. A laboratory upflow fixed bed reactor was fed scrubbed H2S from the biogas and nitrate. Over 95% H2S and 90% nitrate removal were achieved. When fed directly scrubbed H2S, the reactor experienced clogging from elemental sulfur particles. Feeding scrubbed H2S from biogas at pH 8-9 achieved 98% H2S and 97% nitrate removal without clogging. This process biologically converted H2S to elemental sulfur while denitrifying wastewater.
1. The document describes a study on removing NOx from gas by pre-oxidizing NO with ozone and absorbing the oxidation products in alkaline aqueous solutions.
2. Experiments were conducted in a laboratory apparatus to determine the absorption performance of NO oxidation products in solutions of NaOH, KOH, Ca(OH)2, CaCO3, and water. The effect of initial NO concentration and NaOH concentration on NOx removal effectiveness was also examined.
3. Results showed that ozone is effective at oxidizing NO to NO2 in the gas phase. Absorption of oxidation products, particularly in NaOH solutions, allowed high levels of NOx removal to be achieved.
This document summarizes research on catalytic wet air oxidation (CWAO) as an alternative wastewater treatment technique to wet air oxidation (WAO). CWAO uses catalysts to allow for milder operating conditions and shorter reaction times. Experimental results showed that over 50% reduction in chemical oxygen demand (COD) could be achieved in about an hour at temperatures over 200°C and pressures above 30bar using heterogeneous catalysts like palladium on titanium dioxide. The research tested CWAO on various wastewaters and found the most effective catalysts were mixed metal oxide coatings on titanium meshes and ruthenium oxide on titanium dioxide, which constantly decreased COD levels.
This document describes a procedure for determining the chemical oxygen demand (COD) of water samples. COD is a measure of the amount of oxygen required to chemically oxidize organic matter in water. The procedure involves incubating a water sample with potassium dichromate and sulfuric acid, then titrating the excess dichromate with ferrous ammonium sulfate solution. The COD value is calculated based on the volume of ferrous ammonium sulfate used in the titration. The document provides details on the chemicals, apparatus, procedure, sample readings, and calculations for determining COD and interpreting the results.
This document discusses cooling water treatment at a fertilizer plant in India. It provides details on the plant's cooling towers and water chemistry parameters. Cooling water treatment is needed to prevent corrosion, scaling, and microbial fouling of the system. Common issues like corrosion, scaling, and biofouling are discussed along with the mechanisms of corrosion inhibition, scale inhibition, and microbial control through chemical treatment.
This document discusses cooling water analysis and treatment. It covers topics like pH adjustment using sulfuric acid to control scaling, the effects of high pH like increased microbial growth, how much acid is required, chlorine dosing to lower pH and kill bacteria, chlorine demand, factors affecting corrosion like chlorides and stress corrosion cracking of stainless steel, and corrosion inhibition using phosphates. Maintaining the proper delta phosphate is important to control corrosion.
This document provides instructions for measuring chemical oxygen demand (COD) using the dichromate reactor digestion method. Key points include:
- The test measures COD concentrations from 0.7-40 mg/L (ULR range), 3-150 mg/L (LR range), 20-1500 mg/L (HR range), and 200-15,000 mg/L (HR Plus range).
- Samples are digested using COD reagent vials in a heated reactor to oxidize organic compounds. Absorbance of digested samples is then measured colorimetrically.
- Interferences from chloride are removed by mercuric sulfate in the reagent vials. Samples with high chloride must
The chlor-alkali process is an industrial process that uses electrolysis to produce chlorine, sodium hydroxide, and hydrogen from salt water. It involves passing an electric current through a brine solution to drive the following reaction: 2NaCl + 2H2O → 2NaOH + Cl2 + H2. The process was first developed in the 1850s but improved in the 1890s with the mercury cell. Today, membrane and diaphragm cells are more commonly used, accounting for 60% and 14% of European production respectively. The main uses of the products are in polymers, pesticides, antiseptics, acid production, metallurgy, and the paper industry.
Water supply and sewerage engineering laboratoryTaufique Hasan
The document discusses water quality testing performed on samples from the First Ladies Hall of Shahjalal University of Science and Technology, Sylhet. Water samples were tested for various parameters under water supply engineering (drinking water) and sewerage engineering (sewage). For drinking water, tests found the pH, carbon dioxide, turbidity, alkalinity, iron, and manganese levels were all within acceptable limits for drinking water. For sewage, tests were conducted to determine total solids, biochemical oxygen demand, chemical oxygen demand, and chloride. The hardness of the water sample was also found to be within acceptable limits.
Elemental composition study of leachate in some dumpsites in bauchi metropolisAlexander Decker
The document analyzes samples of leachate from four dumpsites in Bauchi, Nigeria to determine concentrations of heavy metals. Complexometric titration methods were used to measure levels of cadmium, chromium, lead and copper. The results found mean concentrations of cadmium ranged from 0.08-0.22 mg/dm3, chromium ranged from 0.01-0.10 mg/dm3, lead ranged from 1.81-2.60 mg/dm3, and copper ranged from 1.11-1.99 mg/dm3. These levels indicate low amounts of heavy metals in the leachates, though their presence still suggests contamination from the dumpsites.
HRSG water chemistry & corrosion controlAbdul Hannan
This document discusses water chemistry and corrosion control in HRSGs. It describes the components of HRSGs, including economizers, steam drums, evaporators, and superheaters. It outlines treatment methods for different sections of the HRSG to control corrosion and deposition, including phosphate and volatile amine treatments. It also discusses common corrosion mechanisms like pitting, crevice, and stress corrosion cracking that can occur in HRSGs and outlines best practices to minimize corrosion.
Nitric acid is a strong acid that is colorless as a pure liquid but commercial samples may appear yellowish. It is highly corrosive and a strong oxidizer. Nitric acid is produced industrially via the Ostwald process, which involves ammonia oxidation over a platinum catalyst in three steps: primary oxidation to nitric oxide, secondary oxidation to nitrogen dioxide, and absorption of nitrogen dioxide in water to form nitric acid. Nitric acid has many industrial and laboratory uses including fertilizer and explosive production.
This document summarizes a study on using electrocoagulation to remove tartrazine dye from simulated wastewater. Tartrazine dye is commonly used in foods, drugs, and textiles but is hazardous. The study investigated the effect of parameters like electrolysis time, dye concentration, pH, and potential on decolorization efficiency. Iron and steel electrodes were used in an electrolytic cell with NaCl electrolyte to treat wastewater samples. Results showed that absorbance decreased with increased time, and maximum removal capacity was achieved. pH was also affected by concentration and time. However, potential changes did not significantly impact absorbance. Overall, electrocoagulation was found to be an effective process for removing the azo dye
The document discusses the use of phosphates in power plant chemistry. It describes phosphate treatment which uses various forms of phosphates like trisodium phosphate to prevent scale and corrosion in boilers. It outlines the reactions that occur during phosphate treatment and highlights hazards like irritation from inhalation or skin contact with phosphates. The document provides guidance on handling, storage, personal protective equipment and first aid measures for phosphates.
This document summarizes a research paper that proposes a FACTS-based Static Switched Filter Compensator (SSFC) scheme for improving power quality when integrating wind energy into smart grids. The SSFC scheme uses controlled switching between two capacitor banks to provide series and shunt compensation. It is controlled using a tri-loop dynamic error controller and VSC controller to mitigate harmonics, stabilize voltages, improve power factor, and reduce losses. Simulation results using Matlab/Simulink show the SSFC scheme improves voltage regulation, reduces current and voltage harmonics to within IEEE limits, and enhances the power factor at generator, load and grid buses compared to without SSFC.
This document summarizes a study that analyzed the chemical composition of wastewater generated from olive oil production and evaluated its potential use as fertilizer on agricultural land. The study found that the wastewater was acidic but rich in organic matter and nutrients like potassium. Soil analysis before and after application of the wastewater showed increases in organic matter and nutrients. Over 280 days, biochemical and chemical oxygen demand of the wastewater decreased by around 50%, indicating its characteristics were modifying. The high potassium and organic content suggests the wastewater could improve soil quality and be a lower-cost fertilizer, though long term effects require more research.
This document summarizes an artificially intelligent investment risk calculation system based on distributed data mining. The system uses a web-based platform to provide registered users investment recommendations and risk assessments based on their financial transaction history. It analyzes data from financial sectors to guide users on investment decisions. It also models an internal bank loan process, tracking employee credibility and targets to distribute profits/losses. The system was developed using HTML, CSS, JavaScript, MySQL, and JSP. It stores user and transaction data in relational databases to power its artificial intelligence algorithms for investment suggestions and risk calculations.
This document summarizes a research paper on developing a reconfigurable hardware architecture for implementing maximum likelihood (ML) decoding algorithms in MIMO systems. It begins by introducing MIMO techniques for improving wireless communication throughput. It then describes various MIMO receiver algorithms and chooses ML for its best performance. The document outlines the ML decoding algorithm and presents a Simulink model. It discusses implementing the MIMO decoder as a modular, reconfigurable architecture on an FPGA and shows placement results on a Xilinx Virtex 4 chip. The work aims to provide flexible hardware for MIMO signal processing applications.
This document summarizes a research paper on developing a smart blood bank system as a cloud-based service. The proposed system aims to address issues with conventional blood bank management systems, especially in rural areas, by providing online access and data sharing capabilities. It utilizes a multi-tenant cloud architecture that allows individual blood banks to register and store their data independently, while also linking the databases to provide a unified search portal for users. The system is intended to improve blood availability information and help connect donors with seekers more efficiently.
This document provides a review of simulation techniques for parallel and distributed computing. It discusses several key topics:
1) It defines parallel computing, distributed computing, and parallel and distributed computing systems. Various classification schemes for parallel and distributed systems are also described.
2) It examines several modeling techniques for parallel and distributed systems including system modeling, network modeling, performance modeling, and mathematical modeling. It provides details on parallel discrete event simulation.
3) It reviews several simulation software tools used for modeling parallel and distributed systems including SimOS, SimJava, and MicroGrid.
4) It concludes with a focused discussion on cloud computing as the latest development in parallel and distributed computing.
Automatic parking and platooning for electric vehicles redistribution in a ca...IOSR Journals
This document describes a system for automatically redistributing electric vehicles between parking stations in a car sharing application. A leader vehicle driven by a human picks up and drops off other vehicles at stations to rebalance availability. The other vehicles can automatically exit parking spaces and join a platoon led by the leader vehicle for transport. An exit parking controller is presented that plans a collision-free path for a vehicle to exit a space in one or multiple maneuvers based on its geometry. Vehicles then follow the leader vehicle longitudinally and laterally in the platoon using control strategies. Perception systems allow vehicles to detect obstacles and other vehicles for safe autonomous maneuvers. The system aims to efficiently relocate vehicles between stations for car sharing applications.
This document analyzes the performance of Wi-Fi networks under three conditions: no fading, flat fading, and dispersive fading. It simulates these conditions using an IEEE 802.11a WLAN physical layer model in Matlab. The simulation measures packet error rate and bit rate as the signal-to-noise ratio and maximum Doppler shift are varied. With no fading, there is no packet error and bit rate increases with SNR. Under flat and dispersive fading, packet error and bit rates are affected differently based on the maximum Doppler shift. The best performance occurs under flat fading with a lower maximum Doppler shift of 100Hz.
Investigation of Reducing Process of Uneven Shade Problem In Case Of Compact ...IOSR Journals
This document investigates reducing uneven shade problems in compact single jersey cotton knit fabrics dyed with turquoise reactive dyes. Scanning electron microscopy shows that stripping and scouring combined increases fabric porosity compared to scouring alone, allowing better dye penetration. Color measurement testing finds that combining stripping and scouring results in more consistent dye absorption and less uneven shading than separate processes, with CMC ΔE values below 1 indicating acceptable color matches. In conclusion, performing stripping and scouring simultaneously on compact single jersey fabrics before dyeing with turquoise reduces uneven dyeing compared to conventional pretreatment methods.
This document provides a review of different classifiers used for text classification on social media data. It discusses how social media data is often unstructured and contains users' opinions and sentiments. Various machine learning algorithms can be used to classify this social media text data, extracting meaningful information. The document focuses on describing Naive Bayes classifiers, which are commonly used for text classification tasks. It explains how Naive Bayes classifiers work by calculating the posterior probability that a document belongs to a certain class, based on applying Bayes' theorem with an independence assumption between features.
This document provides an overview of software fault detection and prevention mechanisms. It discusses several fault detection mechanisms used in the software development lifecycle, including automated static analysis, graph mining, and classifiers. Automated static analysis tools can find standard problems but miss many faults that could lead to failures. Graph mining uses call graph analysis to identify issues in function calling frequencies or structures. Classifiers like NaiveBayes can be trained on normal code behavior to identify abnormal events. The document also discusses fault prevention benefits, related work, and concludes with the importance of fault detection and prevention for developing high quality, reliable software.
This document discusses the use of treated wastewater in concrete. It begins by providing background on wastewater treatment in Kuwait and previous research on using treated wastewater in concrete mixing and curing. The document then details the methodology used, which included designing concrete mixes with 100% cement, 80% cement 20% fly ash, and 80% cement 20% GGBS. Cubes were cast and tested at 7, 14, and 28 days. The results showed compressive strengths over 28 days were similar or higher when using treated wastewater compared to potable water. The conclusion is that treated wastewater can be used in concrete with similar results to potable water, helping address water scarcity issues.
Towards Reducing the Number of Traffic Accidents in Khartoum State (Republic of Sudan)
The study identifies the causes of traffic accidents in Khartoum state and ways to minimize them. A questionnaire was distributed to collect feedback from the public on the causes of accidents and most effective reduction methods. The top causes identified were reckless driving, driving under the influence of alcohol/drugs, and lack of respect for traffic rules. Application of vehicle and road safety standards was found to be lacking. Suggestions to improve safety included increasing enforcement of traffic laws and infrastructure improvements like adding lanes, traffic lights, and pedestrian crossings.
The document describes a digital pen system for handwritten digit and gesture recognition using a trajectory recognition algorithm. The system uses a tri-axial accelerometer, ARM processor, and Zigbee module in a pen-like device to capture acceleration signals from hand motions. The signals are transmitted wirelessly and a trajectory recognition algorithm processes the data through steps of acquisition, preprocessing, feature generation/selection, and extraction to recognize digits and gestures written in air. The system aims to allow for flexible use without limitations of range, environment, or surface that other methods impose.
This document discusses developing a mobile enrollment system for universities in Nigeria. Currently, most university enrollment processes in Nigeria are done manually, which causes long wait times and errors. The authors propose creating a mobile application that would allow students to complete the enrollment process from any location using a mobile device. They conducted a survey that found undergraduate students would most favor such a system and that the main motivations for using a mobile app would be to save time and costs. The authors conclude a mobile enrollment system could speed up the process, reduce errors and provide users with increased convenience and security.
This document summarizes the design and analysis of a shaft-driven transmission for a two-wheeled vehicle. It begins with an introduction to shaft drives and their advantages over chain-driven systems. It then reviews the relevant literature and compares shaft and chain drives. The document describes the components of the shaft-driven system, including bevel gears and the drive shaft. It provides the specifications for the system designed, and calculates various parameters like torque, power, stresses, strains, and deflection. The results show that the shaft-driven system can meet the design requirements. In conclusion, the shaft-driven transmission is analyzed to be a viable alternative to chain-driven systems for two-wheelers.
This document proposes a method for completing user profiles using their online social circles. It introduces the task of user profile completion and discusses how existing approaches do not leverage users' real social circles. The method presented uses non-negative matrix factorization to decompose a circle-profile matrix into a circle-user matrix and user-profile matrix. This allows the model to detect a user's multi-dimensional social characteristics from their various social circles. Experimental results on Facebook, LinkedIn, and Microsoft Academic Search datasets show the approach outperforms state-of-the-art methods for user profile completion.
This document describes the development of an algorithm for a 16-bit Wallace tree multiplier (WTM). It begins with background on binary multipliers and discusses methods like ripple carry array and Wallace trees. The Wallace tree approach is analyzed in more detail, outlining its three main steps: partial product generation, reduction stages using adders, and final addition. The document then proposes improvements to the partial product generation step to reduce complexity from O(n2) to O(n). It also presents a scheme for clearly representing signals in the different reduction stages. Finally, the design is synthesized for an FPGA and simulation results are shown comparing the WTM to other multipliers in terms of delay, area, power-delay product,
This document proposes an energy efficient three-level model for query optimization in wireless sensor networks (WSNs). At the three levels are: base station, cluster heads, and sensor nodes. The base station maintains metadata about cluster heads and sensor nodes. When a query is received, it first checks if the result is cached. If not, it checks the status of cluster heads and selects a new cluster head if needed. The query is then disseminated to cluster heads using a modified Bellman-Ford algorithm. Cluster heads aggregate data from relevant sensor nodes and send the result to the base station. This model aims to minimize communication costs during query processing in WSNs.
The document experimentally investigates conditions for producing hypochlorous acid water with high efficiency. It examines the effects of electrode plate interval, current density, flow rate, and sodium chloride concentration on the production efficiency of available chlorine. The experiments find that production efficiency is strongly affected by flow rate and current density. Higher flow rates and lower current densities result in higher production efficiencies, even as available chlorine concentration increases. An optimal sodium chloride concentration of around 20,000 mg/l achieves high efficiency without further increase at higher concentrations.
The document experimentally investigates conditions for producing hypochlorous acid water with high efficiency. It examines the effects of various parameters on the production efficiency, defined as the ratio of actual available chlorine produced to the theoretical maximum. Tests were conducted using a flow reactor with parallel electrode plates and no separating membrane. Results show that production efficiency is strongly affected by flow rate and current density. Higher flow rates and lower current densities yielded more efficient production, with an optimum efficiency found around 20,000 mg/L NaCl concentration. Maintaining appropriate conditions can lead to high concentration, high efficiency hypochlorous acid production.
This document describes a new method for producing bleach using a zero-gap electrolysis cell with three compartments separated by ion exchange membranes. The goal is to generate hypochlorous acid at high levels in the anode compartment by continuously adjusting the pH between 4.5-5.5. Caustic soda would be produced in the cathode compartment while brine is supplied to the central compartment. Hypochlorous acid from the anode compartment would then be neutralized with sodium hydroxide to produce bleach with active chlorine contents close to 1.8%. The document discusses membrane properties, operating conditions, and results obtained with this new method for producing higher concentration bleach using a zero-gap electrolysis cell.
Investigation on the Effect of TiO2 and H2O2 for the Treatment of Inorganic C...inventy
Sodium hypochlorite (NaClO) is regularly used as a disinfectant or a bleaching agent because of its high efficiency against many bacteria and viruses present in seawater along with its cheaper cost. Now a days, with the increase in the environmental concerns concerning the use of chlorination for the disinfection or bleaching of treated water related to the formation of potentially harmful chloro-organic by products through reactions with natural organic matter (NOM), it is preferred to implement a process with environmentally friendly chemicals for water treatment processes. About This report aim to study the possibility of reducing the inorganic carbon present in seawater by oxidization reaction of seawater with TiO2 and H2O2. Investigated and a comparison between thin film method and suspension method with a reactor system in conjunction with a light concentrating system has been done.
This document describes research into using alkaline zinc hydroxide solution as an electrolyte for hydrogen generation through water electrolysis. The solution is prepared by dissolving zinc oxide in sodium hydroxide or potassium hydroxide solutions, forming sodium zincate or potassium zincate. Experimental results showed that using these solutions as electrolytes can enhance the hydrogen evolution rate compared to conventional electrolytes. Specifically, sodium zincate increased the rate by a factor of 2.74 and potassium zincate by 1.47. The zincate solutions may improve ionic conductivity and electrode catalytic activity for hydrogen evolution. This research could help optimize alkaline water electrolysis systems for more efficient hydrogen production.
The document discusses several methods for producing hydrogen through water splitting, including:
- Steam reforming of methane, the most common current method.
- Electrolysis, where an electric current splits water into hydrogen and oxygen. More efficient variations include steam electrolysis and thermochemical electrolysis.
- Photochemical and photobiological systems use sunlight to drive the water splitting reaction.
- Thermal water splitting uses very high temperatures of around 1000°C.
- Gasification and biomass conversion also produce hydrogen from other feedstocks.
Low current electrolysis is discussed as a more efficient method, similar to the water splitting that occurs in photosynthesis. Producing hydrogen directly from water without electrolysis is also mentioned. Overall
Plasma-chemical treatment of industrial wastewaters from brewery “Brasseries ...IJERA Editor
This document summarizes a study on treating industrial wastewater from a brewery in Cameroon using plasma-chemical treatment. The researchers collected wastewater samples from the central collection point of the brewery and analyzed them to determine pollution levels. They then exposed the samples to a gliding arc plasma discharge for periods of 3-60 minutes. Exposing the wastewater to 60 minutes of the plasma discharge reduced turbidity by 52.22% and absorbance by 50.19%, indicating degradation of colored compounds. After 60 minutes of treatment, levels of biochemical oxygen demand, chemical oxygen demand, and total organic carbon in the wastewater were also reduced significantly, by 52.05%, 68.63%, and 69
Plasma-chemical treatment of industrial wastewaters from brewery “Brasseries ...IJERA Editor
This work focuses on the study of the chemical reactivity of an advanced oxidation process (AOP), called the
plasma technique, in order to prevent industrial effluent from pollution and better cope to several damage of
environment. The oxidizing and acidifying properties of an electric discharge of the gliding arc plasma and its
application to a target which is a real effluent (wastewater from Brasseries du Cameroun -Bafoussam plant)
fascinated this study. Samples were collected from the central collecting point (CCP) of the effluent. The
collected effluent samples were analyzed by volumetric and instrumental methods, and then exposed to the
gliding discharge during specific time periods of 3-60 min to exhibit the desired decontamination effects. At the
end of 60 min of exposure time to the discharge, 52.22% and 50.19% obtained respectively to abatement of
turbidity and rate of fall in absorbance. This reduction can be explained by the fact that the coloured compounds
were degraded and this degradation gave rise to the transparent appearance observed. After stopping the
discharge process, the abatement percentage of BOD5, COD and TOC, were obtained at the same time (60min)
with values of 52.05%, 68.63% and 69.37% respectively. These results reflect the considerable reduction of the
pollution load of the wastewaters collected from CCP of the brewery. These results showed that the
effectiveness of the gliding arc plasma depends not only on the physico-chemical parameters of the target, but
also on the exposure time and concluded that the non-thermal plasma process alone provides good reduction of
organic pollutants in wastewater. Moreover, the phenomenon of post- discharge, even though not studied in
details demonstrated that, after switching the discharge, the evolution of parameters such as pH, electrical
conductivity and TDS increase.
Separation of calcium carbonate and barium sulphate from a mixed sludge prduc...Timothy Rukuni
South Africa is one of the first countries to implement full-scale mine water reclamation to drinking water quality. Reverse osmosis is already being used on full scale for desalination of mine water. However, with increased recycling of mine water, the result has been the increased generation of sludge. The Council for Scientific and Industrial Research (CSIR) has developed the Alkali-Barium-Carbonate (CSIR-ABC) process that can be used for neutralization and desalination of sulphate-rich effluents while recovering valuable by-products from the mixed sludges produced. A mixture of BaSO4 and CaCO3 sludge is produced as one of the by-products, which preferably needs to be separated into its components prior to thermal treatment. The aim of this study was to separate CaCO3 and BaSO4 from a CaCO3-BaSO4 mixed sludge through dissolution of CaCO3 as Ca(HCO3)2 in contact with CO2. Measured quantities of a simulated CaCO3-BaSO4 mixed sludge from the CSIR-ABC process were fed into a reactor vessel containing deionized water and pressurized CO2 was introduced. The effects of temperature and pressure with time were investigated while monitoring alkalinity, pH and calcium concentration. The findings of this study were: (1) The dissolution rate of CaCO3 was rapid i.e. from 0 to 2000mg/L in the first 20 minutes; (2) Ca(HCO3)2 had a high solubility of about 2 600 mg/L when in contact with CO2 at 1 atm., while BaSO4 was almost completely insoluble; (3) The solubility of Ca(HCO3)2 increased with decreasing temperature and increasing pressure; (4) CaCO3, after conversion to Ca(HCO3)2, was separated from BaSO4 in a CaCO3-BaSO4 mixed sludge; (5) Visual MINTEQ model is a powerful tool that can be used to predict the solubilities of CaCO3 and BaSO4 when contacted with CO2.
J. Electrochem. Soc.-2003-Frank-C244-50Aaron Frank
This document analyzes the decomposition of sulfopropyl sulfonate (SPS), an additive used in acid copper electroplating. Through various analytical techniques, the researchers determined that the primary decomposition product of SPS is a thiolsulfonate. While hydrogen peroxide can oxidize SPS to form this product, experiments showed oxygen reduction on copper forms water, not peroxide. The data suggests SPS stabilizes Cu(I) and this complex is the intermediate; oxygen then reacts with the SPS/Cu(I) complex to form the thiolsulfonate decomposition product and Cu(II). Understanding this decomposition mechanism could help extend the lifespan of copper plating baths.
This document summarizes an experiment on using electrocoagulation with iron electrodes to remove mercury from wastewater. Key findings include:
1) Maximum mercury removal of 94.5% was achieved after 40 minutes of electrocoagulation at an applied potential of 9V, agitation of 400 rpm, initial pH of 4.5, and electrolyte concentration of 1.333 g/L.
2) Higher applied potentials and agitation rates decreased mercury removal efficiency due to excessive oxygen generation and unsuitable floc formation.
3) Operating costs were calculated based on energy consumption and electrode material costs. Electrocoagulation was found to be an efficient and fast method for mercury removal compared to conventional techniques.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Bio hydrogen production from waste materialsappurajan
This document discusses various methods for producing hydrogen gas including electrolysis of water, steam reforming of hydrocarbons, auto-thermal processes, and biological processes. It provides details on the mechanisms, requirements, advantages and limitations of each method. Electrolysis of water produces hydrogen through the use of electricity to split water into hydrogen and oxygen gases. Steam reforming and auto-thermal reforming use heat and catalysts to produce hydrogen from methane or other hydrocarbons. Biological methods use microorganisms and organic materials to product hydrogen through photosynthesis or fermentation.
Laboratory manual of water supply and sewerage engineeringTaufique Hasan
This document provides the procedure for determining the total alkalinity of water through titration. It defines alkalinity as the capacity of water to neutralize acids and discusses the significance of alkalinity measurements in water and wastewater treatment. The procedure involves titrating a water sample with sulfuric acid to two end points using phenolphthalein and methyl orange indicators. The ml of acid used is then used to calculate the total, hydroxide, carbonate, and bicarbonate alkalinity concentrations in the sample.
This document summarizes a study on using electrocoagulation with aluminum electrodes to remove mercury from wastewater. The study investigated the effect of electrolyte concentration, initial mercury concentration, applied potential, pH, and agitation on mercury removal efficiency. Optimum conditions for 98.5% mercury removal within 50 minutes included a pH of 4.5, initial concentration of 50 ppm, applied potential of 9V, electrolyte concentration of 1.333 g/L, and agitation of 400 rpm. Under these conditions, aluminum ions are generated from the anode which forms hydroxide flocs that adsorb and remove mercury from the wastewater through processes like coagulation, adsorption, and precipitation.
This document summarizes a study that evaluated factors influencing the production of sodium hydroxide (NaOH) using an ion exchange membrane electrolytic cell. The study tested different initial NaOH concentrations, applied voltages, and temperatures. Experiments used a model NaCl solution and measured changes in NaOH concentration, conductivity, and pH over 150 minutes. Results showed these parameters increased linearly with electrolysis time. The current efficiency was on average 80.2%, indicating good cell performance.
Basic Thermal Power Plant Chemistry, for Operational Staff.Syed Aqeel Ahmed
The document provides an overview of water chemistry training for power plant operators. It discusses the importance of controlling water quality to prevent scale, corrosion, and biological growth in power plant systems. It covers external water treatment processes like clarification, filtration, and desalination. It also summarizes internal water treatment including oxygen scavenging, pH control, and use of chemicals like hydrazine. Key water quality parameters that are monitored like conductivity, pH, chlorides, and sodium are explained. The document provides troubleshooting guidance and emphasizes the importance of detecting condenser leakage to prevent contamination of boiler water.
IRJET- Study the Effect of Process Parameters during Electrochemical Treatmen...IRJET Journal
This document discusses using electrochemical treatment to study the effect of process parameters on treating wastewater. It aims to optimize the removal of pollutants like phenol, dyes, and bacteria from textile industry effluent. The researchers will analyze how factors like pH, conductivity, electrolysis concentration, current density affect treatment. The electrochemical method uses electrodes to generate metal ions that neutralize pollutant charges and facilitate removal. The document examines this process in detail, outlines the experimental setup and method, and presents results showing increased phenol removal at higher pH levels and longer treatment times.
This document discusses a feasibility analysis of using liquid organic hydrides (LOH) to transport hydrogen in a chemical bonded form at ambient temperature and pressure for hydrogen delivery. Specifically, it analyzes a system that produces 10 kg/h of hydrogen using methylcyclohexane as the hydrogen carrier, which undergoes catalytic dehydrogenation to produce hydrogen. The analysis found the system has a hydrogen storage capacity of 6.8 wt% and 60 kg/m3, and the energy transported to energy consumed ratio is about 3.9. It also calculates the total carbon footprint reduction of 345 tons/year of CO2 emissions per station by replacing gasoline with hydrogen. The document concludes LOH technology has significant technical and economic potential for hydrogen delivery.
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
This document describes the design of an intelligent autonomous wheeled robot that uses RF transmission for communication. The robot has two modes - automatic mode where it can make its own decisions, and user control mode where a user can control it remotely. It is designed using a microcontroller and can perform tasks like object recognition using computer vision and color detection in MATLAB, as well as wall painting using pneumatic systems. The robot's movement is controlled by DC motors and it uses sensors like ultrasonic sensors and gas sensors to navigate autonomously. RF transmission allows communication between the robot and a remote control unit. The overall aim is to develop a low-cost robotic system for industrial applications like material handling.
This document reviews cryptography techniques to secure the Ad-hoc On-Demand Distance Vector (AODV) routing protocol in mobile ad-hoc networks. It discusses various types of attacks on AODV like impersonation, denial of service, eavesdropping, black hole attacks, wormhole attacks, and Sybil attacks. It then proposes using the RC6 cryptography algorithm to secure AODV by encrypting data packets and detecting and removing malicious nodes launching black hole attacks. Simulation results show that after applying RC6, the packet delivery ratio and throughput of AODV increase while delay decreases, improving the security and performance of the network under attack.
The document describes a proposed modification to the conventional Booth multiplier that aims to increase its speed by applying concepts from Vedic mathematics. Specifically, it utilizes the Urdhva Tiryakbhyam formula to generate all partial products concurrently rather than sequentially. The proposed 8x8 bit multiplier was coded in VHDL, simulated, and found to have a path delay 44.35% lower than a conventional Booth multiplier, demonstrating its potential for higher speed.
This document discusses image deblurring techniques. It begins by introducing image restoration and focusing on image deblurring. It then discusses challenges with image deblurring being an ill-posed problem. It reviews existing approaches to screen image deconvolution including estimating point spread functions and iteratively estimating blur kernels and sharp images. The document also discusses handling spatially variant blur and summarizes the relationship between the proposed method and previous work for different blur types. It proposes using color filters in the aperture to exploit parallax cues for segmentation and blur estimation. Finally, it proposes moving the image sensor circularly during exposure to prevent high frequency attenuation from motion blur.
This document describes modeling an adaptive controller for an aircraft roll control system using PID, fuzzy-PID, and genetic algorithm. It begins by introducing the aircraft roll control system and motivation for developing an adaptive controller to minimize errors from noisy analog sensor signals. It then provides the mathematical model of aircraft roll dynamics and describes modeling the real-time flight control system in MATLAB/Simulink. The document evaluates PID, fuzzy-PID, and PID-GA (genetic algorithm) controllers for aircraft roll control and finds that the PID-GA controller delivers the best performance.
zkStudyClub - LatticeFold: A Lattice-based Folding Scheme and its Application...Alex Pruden
Folding is a recent technique for building efficient recursive SNARKs. Several elegant folding protocols have been proposed, such as Nova, Supernova, Hypernova, Protostar, and others. However, all of them rely on an additively homomorphic commitment scheme based on discrete log, and are therefore not post-quantum secure. In this work we present LatticeFold, the first lattice-based folding protocol based on the Module SIS problem. This folding protocol naturally leads to an efficient recursive lattice-based SNARK and an efficient PCD scheme. LatticeFold supports folding low-degree relations, such as R1CS, as well as high-degree relations, such as CCS. The key challenge is to construct a secure folding protocol that works with the Ajtai commitment scheme. The difficulty, is ensuring that extracted witnesses are low norm through many rounds of folding. We present a novel technique using the sumcheck protocol to ensure that extracted witnesses are always low norm no matter how many rounds of folding are used. Our evaluation of the final proof system suggests that it is as performant as Hypernova, while providing post-quantum security.
Paper Link: https://eprint.iacr.org/2024/257
Introduction of Cybersecurity with OSS at Code Europe 2024Hiroshi SHIBATA
I develop the Ruby programming language, RubyGems, and Bundler, which are package managers for Ruby. Today, I will introduce how to enhance the security of your application using open-source software (OSS) examples from Ruby and RubyGems.
The first topic is CVE (Common Vulnerabilities and Exposures). I have published CVEs many times. But what exactly is a CVE? I'll provide a basic understanding of CVEs and explain how to detect and handle vulnerabilities in OSS.
Next, let's discuss package managers. Package managers play a critical role in the OSS ecosystem. I'll explain how to manage library dependencies in your application.
I'll share insights into how the Ruby and RubyGems core team works to keep our ecosystem safe. By the end of this talk, you'll have a better understanding of how to safeguard your code.
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
Inconsistent user experience and siloed data, high costs, and changing customer expectations – Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
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F012524857
1. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)
e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 12, Issue 5 Ver. II (Sep. - Oct. 2015), PP 48-57
www.iosrjournals.org
DOI: 10.9790/1684-12524857 www.iosrjournals.org 48 | Page
Experimental Investigation on Hypochlorous Acid Water
Production using Electrode Plates without a Barrier Membrane
(Part I: Production conditions for high-concentration
Hypochlorous acid water)
Naoki Maruyama, Masahiro Noda, Hiroaki Goshima, Motohide Okamoto,
Masafumi Hirota
(Division of Mechanical Engineering, Graduate School of Engineering, Mie University,
1577 Kurimamachiya-cho, Tsu 514-8507, Japan)
Abstract: Available chlorine has been widely used for the sterilization and disinfection of the tap water supply.
The development of a device is awaited which will enable the generation of available chlorine at high
concentrations with high efficiency. The purpose of this paper is to propose optimum operation conditions for
available chlorine production from the standpoint of high concentration. The experiment is conducted using a
flow-type reactor with narrow and parallel electrode plates, even though it lacks a barrier membrane between
the plates. The governing factors are the electrode plate interval and the flow rate of sodium chloride solution
from the viewpoint of hydrodynamics, and the concentration of sodium chloride of the medium and current
density supplied to the electrode plates from the standpoint of chemical reactions. The concentration of
available chlorine was measured using a residual chlorine meter. The influence of operation conditions on the
concentration of available chlorine is shown. Moreover, the governing factors are examined using experimental
design because many experimental conditions are expected for the above conditions. As a result, the high
concentration production of available chlorine is strongly affected by the current density as well as sodium
chloride concentration. These results will be useful for producing chlorinated water, called hypochlorous acid
water.
Keyword: Hypochlorous acid water, Concentration, Available chlorine, Parallel electrode plates,
Experimental design, Experiment
I. INTRODUCTION
The supply of safe drinking water is very important for sustainable human life. An abundant supply of
drinking water from a faucet remains insufficient in many developing countries. Unpurified water leads to
infection and disease. Hypochlorous acid water, which contains available chlorine, is useful for the sterilization
and disinfection of the tap water supply [1, 2]. In addition, disinfected water is in demand from a medical
standpoint because it is used in measures dealing with natural calamities [3]. In this case, a highly concentrated
disinfectant or the on-site production of disinfected water is desired in order to reduce transport capacity. As a
sterilization disinfectant, it is widely used to disinfect devices and various apparatuses, e.g., in the
manufacturing process of various foods including the disinfection of drinking water, fruits, vegetables, and dairy
products [4]. The bactericidal effects of available chlorine are useful to the marine products industry as well as
the food industry. As an example, the disinfection of water for the aquaculture of seed production is very
important for preventing the spread of infectious disease [5]. In addition, the production efficiency of available
chlorine is also important from the standpoint of energy consumption for production. Therefore, the
development of a simple device is needed which makes it possible to produce available chlorine at a high
concentration with a high efficiency. The characteristics of available chlorine and related chemical substances
have been investigated in detail [6-11].
The purpose of this paper is to examine parameters influencing the production of hypochlorous acid
water with emphasis on obtaining a high concentration [12, 13]. In the experiment, hypochlorous acid water is
produced by the electrolysis of sodium chloride solution. Hypochlorous acid water with gas flows between the
anode and cathode electrode plates, and with no membrane separating the flow between the electrode plates.
Gas and liquid two-phase flow in narrow and parallel electrode plates is examined, where gas is generated
during the experiment by chemical reactions and becomes an obstacle for the chemical reactions. The
concentration of hypochlorous acid is evaluated by changing the electrode interval, electric current density, flow
rate and concentration of sodium chloride solution.
2. Experimental Investigation on Hypochlorous Acid Water Production using Electrode Plates ...
DOI: 10.9790/1684-12524857 www.iosrjournals.org 49 | Page
II. HYPOCHLOROUS PRODUCTION MECHANISM
2.1 Available chlorine
Available chlorine is a generic name for chlorine that shows bactericidal action. Free chlorine and
combined chlorine are both included in available chlorine. The free chlorines are hypochlorous acid (HClO),
hypochlorous acid ion (OCl-
) and chlorine gas (Cl2) [14-16]. These three kinds of free chlorine change their
respective existence ratios based on pH, as shown in Fig. 1. In this experiment, almost all of the free chlorine in
the solution is HClO, because the produced solution becomes around pH 5 [16]. Table 1 shows the principal
characteristics of HClO [9]. The order of antiseptic capability is Cl2 < OCl-
< HClO. HClO shows the strongest
bactericidal activity in free chlorines. Free chlorine destroys the cell films and the cell walls of microorganisms
and viruses using its strong oxidation, and sterilization or disinfection effects are demonstrated by the
degeneration of an internal protein and nucleic acid. Moreover, HClO exists only as an aqueous solution, and it
can be obtained in a solution of up to 25%. It is readily susceptible to heat, and the decomposition of HClO to
hydrochloric acid HCl, oxygen O2 and chloric acid HClO3 are promoted at water temperatures of over 44 ºC
[17]. Therefore, it is necessary to note the temperature of the aqueous solution.
0.0
0.2
0.4
0.6
0.8
1.0
1 2 3 4 5 6 7 8 9 10
pH
Rateofexistence[-]
HClO
OCl-
Cl2
0.0
0.2
0.4
0.6
0.8
1.0
1 2 3 4 5 6 7 8 9 10
pH
Rateofexistence[-]
HClO
OCl-
Cl2
Figure 1. Forms of free chlorine
Table 1. Properties of HClO
Structural diagram H - O - Cl
Dissociation constant KHClO
2.95x10-8
mol/l
(HClO H+
+ ClO-
)
Molecular weight MHClO 52.45 g/mol
Degradation temperature 44 ºC
Oxidation number +1
2.2 HClO production mechanism
It is necessary to add chloride to water as an electrolysis auxiliary agent in order to produce HClO.
Sodium chloride, NaCl, is used as an electrolysis auxiliary substance in this experiment because its treatment is
safe and easy. Figure 2 shows a production process for HClO that uses no diaphragm electrolyzer [12, 13]. NaCl
is dissociated into chloride ion Cl-
and sodium ion Na+
in water. At the anode, H2O is decomposed into O2 and
H+
by oxidation action, and Cl2 is produced from Cl-
also by oxidation action. The production of Cl2 occurs
preferentially over H2O decomposition because Cl-
is a halogen ion. Although almost all produced Cl2 is
released outside as a gas, part of it is dissolved into H2O and produces HClO. On the other hand, at the cathode,
an electron is given to H2O by a reducing process, and H2 and hydroxide ion OH-
are produced. Sodium ion Na+
produced at the cathode combines with hydroxide OH-
, and then sodium hydroxide NaOH is produced. In
addition, Na+
combines with HCl and hypochlorous acid HClO, then NaCl and sodium hypochlorite NaClO are
also produced in the solution, too. NaClO also exhibits bactericidal action [18-21].
Figure 3 shows the relation of electric potential and voltage in a reactor consisting of electrode plates
with electrolytic solution [22-26]. The electrified state of the electrode plates can be controlled by the
application of voltage to the plates. The distribution of ions which have an opposite charge to the electrode
plates will change in proportion of the electrified state. The electric potential is divided into three types that are
caused at each layer, such as the Helmholtz double layer, the diffuse electric double layer and other solution
regions, as shown in Fig. 3. The electric double layer, and especially the Helmholtz double layer, has a property
of accumulating electricity. The electric potential of the solution resistance becomes lower as the concentration
of ions in the electrolyte solution becomes higher. Generally, almost all impressed voltage to the electrode plates
is consumed at the Helmholtz double layer.
3. Experimental Investigation on Hypochlorous Acid Water Production using Electrode Plates ...
DOI: 10.9790/1684-12524857 www.iosrjournals.org 50 | Page
Dissociation of NaCl
NaCl Na+ + Cl-
Anode
HClO production
Cathode
2H2O O2 + 4H+ + 4e-
2Cl- Cl2 + 2e-
2H2O + 2e- H2 + 2OH-
Cl2 + H2O HClO + H+ + Cl-
H2
OH-
2Cl-
Cl2
Na+
H2O
2H+
2H2O
H2O
Cathode
Anode
NaCl solution
(NaCl Na+ + Cl-)
HClO +H++Cl-Cl2+H2O
O2
2
1
HClO H+ + ClO-
Dissociation of NaCl
NaCl Na+ + Cl-
Anode
HClO production
Cathode
2H2O O2 + 4H+ + 4e-2H2O O2 + 4H+ + 4e-
2Cl- Cl2 + 2e-
2H2O + 2e- H2 + 2OH-2H2O + 2e- H2 + 2OH-
Cl2 + H2O HClO + H+ + Cl-Cl2 + H2O HClO + H+ + Cl-
H2
OH-
2Cl-
Cl2
Na+
H2O
2H+
2H2O
H2O
Cathode
Anode
NaCl solution
(NaCl Na+ + Cl-)
NaCl solution
(NaCl Na+ + Cl-)
HClO +H++Cl-Cl2+H2O HClO +H++Cl-Cl2+H2O
O2
2
1
O2
2
1
HClO H+ + ClO-HClO H+ + ClO-
Electricpotential
V
A
Electric potential of solution resistance
Helmholtz double layer
(Compact layer)
Diffuse electrical double layer
Anode
Cathode
Impressedvoltage
Electrical double layer
Electricpotential
VV
AA
Electric potential of solution resistance
Helmholtz double layer
(Compact layer)
Diffuse electrical double layer
Anode
Cathode
Impressedvoltage
Electrical double layer
Figure 2. HClO production process Figure 3. Relation of electric potential and voltage
III. EXPERIMENTAL APPARATUS AND PROCEDURE
3.1 Experimental apparatus
The experimental apparatus employed in this experiment is shown in a decomposed state in Fig. 4. The
system consists of the test section, tubing pump, power supply for electrolysis, data logger for recording applied
voltage and local temperature, clamping meter for the current measurement and the beaker for inspection [12,
13]. In this system, NaCl solution passes between the narrow electrode plates, that is, a flow-type electrolysis
device without a membrane separator. The interval between the titanium electrode plates, d, is changed using
spacers of several thicknesses. The aspect ratio of the electrode is 100 mm x 50 mm in height and width,
respectively. In addition, the reaction area, S, of each electrode plate is the same. A sight glass is placed at the
exit region of the reactor in order to observe the behavior of the bubbles created by the chemical reaction. An
electrode made by a titanium plate coated with a thin layer of platinum is applied [27]. The thickness of the plate
is 0.5 mm and the platinum is 50 um. The thermocouples are fitted on the back side of the titanium plate to
observe the plate temperatures which are then recorded by a data logger. Each titanium electrode plate is fixed
to a 30 mm thick acrylic plate, with the titanium electrode plates fixed parallel to one another. The joint surface
of each element of the device is sealed by O-rings. A small chamber with parallel thin tubes is set at the entrance
region of the test section in order to have a uniform stream over the inlet cross section.
V
Electrode plate
Electrolysis area
NaCl solution
DC Power supply
Reactor
HClO solution
Tubing pumpx: Thermocouple
A
+ -
Sight glass
Beaker
Parallel thin tubes
Exit chamber
V
Electrode plate
Electrolysis area
NaCl solution
DC Power supply
Reactor
HClO solution
Tubing pumpx: Thermocouple
A
+ -
Sight glass
Beaker
Parallel thin tubes
Exit chamber
Thermocouples
Electrode plate
Sight glass
Exit chamber
Thermocouples
Electrode plate
Sight glass
Exit chamber
(a) Schematic layout of experimental apparatus (b) Photo of reactor
Figure 4. Experimental apparatus employed in this experiment
3.2 Experimental procedure
Firstly, the decomposition voltage of the NaCl solution is measured for each NaCl concentration,
electrode plate interval and flow rate to find a minimum impressed voltage. Then, the experiment is started. At
4. Experimental Investigation on Hypochlorous Acid Water Production using Electrode Plates ...
DOI: 10.9790/1684-12524857 www.iosrjournals.org 51 | Page
the beginning of the experiment, the flow temperature is unstable as the electrode plates are heated because of
Joules’ law. After the steady state condition is achieved, HClO solution, local temperatures, impressed voltage
and current are measured.
A residual chlorine meter is introduced to measure the concentration of available chlorine by means of
the absorptiometric method using a DPD (Diethyl-Phenylene-Diamine) reagent. The concentration of collected
available chlorine is too dense to measure using a residual chlorine meter. Therefore, the collected solution is
diluted to a predetermined magnification using purified water in order to obtain the optimum range of
concentration for the meter. The measured value is multiplied corresponding to the above magnification factor
to provide a true dimension.
3.3 Theoretical decomposition voltage of NaCl solution
In order to produce HClO from a NaCl solution by electrolysis, Cl2 has to be produced at the anode
side, as shown in Fig. 2. The minimum voltage to produce Cl2 should be confirmed theoretically before the
experiment. First, the standard electrode potentials of each electrode plate are estimated. The electrolysis will
begin over this electrode potential. The standard electrode potential is derived using standard Gibbs energy of
formation. The standard Gibbs energy of formation
G is emitted from each electrode plate as an electric
energy.
VnFG
(1)
Here, n is the electron count that participates in the reaction, F is a Faraday's constant 4
1065.9 F C/mol, and
V is the electric potential difference.
The reaction at an anode plate, Cl2 is produced from Cl-
as shown in Eq. (2).
2Cl-
Cl2 + 2e-
(2)
Therefore, the electric potential difference, 2ClV , required to produce Cl2 is estimated by Eq. (1)
because 1 mole of electron reacts with 1 mole of Cl-
.
nF
G
V
)Cl(
2Cl
36.1
)1065.9(1
1023.131
4
3
V (3)
Here, )Cl(
G = -131.23 kJ/mol at 25 ºC, 1 atmosphere [28].
On the other hand, at a cathode plate, H2 is produced from H2O as shown in Eq. (4).
2H2O + 2e-
H2 + 2OH-
(4)
The electric potential difference, 2HV , required to produce H2 is estimated by Eq. (1) as follows
because 2 moles of electron reacts with 1 mole of H2.
nF
G
V
)OH(
2H
81.0
)1065.9(2
1024.157
4
3
V (5)
Here, )OH(
G = -157.24 kJ/mol at 25 ºC, 1 atmosphere [28]. Therefore, the overall reaction needed to
produce HClO is shown in Eq. (6).
Cl2 + H2O HClO + H+
+ Cl-
(6)
As a result, the electric potential difference between anode and cathode electrode plates is estimated as
follows.
5. Experimental Investigation on Hypochlorous Acid Water Production using Electrode Plates ...
DOI: 10.9790/1684-12524857 www.iosrjournals.org 52 | Page
22 HClHClO VVV
17.281.036.1 V (7)
The electric potential difference, called the decomposition voltage, 17.2HClO V V is required
theoretically to produce HClO. The decomposition voltage will increase slightly in the experiment because the
electrolytic solution includes infinitesimal impurities and because of overvoltage at the electrode plates.
IV. EXPERIMENTAL RESULTS AND DISCUSSION
4.1 Current-voltage characteristics of electrode plates
In order to confirm the characteristics of the electrode plate, the current-voltage relationship is
important to setup an experimental condition. Figure 5 shows a current-voltage relation for the concentration of
NaCl CNaCl = 50,000 mg/l and volume flow rate Q =0.0551 ml/s as an example. In this experiment, the
decomposition voltage for the reaction is estimated to be around 2.2 Vdc. Therefore, the voltage between
electrode plates is set at over 2.2 Vdc in this experimental condition.
0
200
400
600
800
1,000
1,200
0.00 1.00 2.00 3.00 4.00 5.00
Impressed voltage V [Vdc]
CurrentdensityIs[A/m2]
1.0 mm
3.0 mm
5.0 mm
Electrode plate interval
0
200
400
600
800
1,000
1,200
0.00 1.00 2.00 3.00 4.00 5.00
Impressed voltage V [Vdc]
CurrentdensityIs[A/m2]
1.0 mm
3.0 mm
5.0 mm
Electrode plate interval
Figure 5. Example of current-voltage relation (CNaCl = 50,000 mg/l, Q =0.0551 ml/s)
4.2 Index for high-concentration production
The purpose of this study is to produce HClO at a high-concentration. The production at a high
efficiency is also important. However, this is next to impossible to carry out simultaneously. Therefore, the
concentration and efficiency of the produced HClO are evaluated individually.
The basic balance condition may be expressed as follows:
F
SI
M
CQ s
NaCl
NaCl
6
10
(8)
Here, CNaCl is the concentration of the NaCl solution [mg/l], Q is the flow rate of the NaCl solution [ml/s],
MNaCl is the molecular weight of the NaCl [g/mol], F is the Faraday’s constant [C/mol], Is is the current density
supplied to the electrode [A/m2
], and S is the reaction area [m2
]. This is configured to be equal to the number of
moles of both Cl-
and e-
. The supplied current density on the electric plates is estimated by Eq. (8). Then, after
the influence of concentration of NaCl solution on the available chlorine concentration is recorded, the current
density and flow rate of the NaCl solution will be changed for the electrode plate intervals.
There are many experimental conditions in this experiment. Therefore, the narrowing of experimental
conditions is introduced in this experiment in order to obtain the influence of these experimental parameters.
Firstly, the influence of the NaCl concentration in the solution, CNaCl, on the available chlorine concentration,
CAC, is evaluated for plate intervals with a constant flow rate. Next, the influence of the current density, Is,
supplied to the electrode plate on the CAC is examined for the CNaCl where the higher CAC was obtained. Then,
the influence of the flow rate of solution on the CAC is examined based on the optimum CNaCl and Is. Finally, the
influence of the plate interval, d, on the CAC is examined based on the optimum amounts of CNaCl, Is and Q . The
electrode plate intervals are varied in each experiment because the bubbles generated by the chemical reaction
affect the effective reaction area of the electrode plates.
6. Experimental Investigation on Hypochlorous Acid Water Production using Electrode Plates ...
DOI: 10.9790/1684-12524857 www.iosrjournals.org 53 | Page
4.3 Dependence of NaCl concentration of solution flowing into a reactor
The NaCl concentration in the solution flowing into a reactor, CNaCl, is varied to show the influence of
Cl-
on available chlorine production. Table 2 and Fig. 6 show the experimental results for a constant flow rate
and several plate intervals. As the NaCl concentration increases and the electrode plate interval becomes larger,
the available chlorine concentration, CAC, increases. The reason is that the increase in the abundance of Cl-
will
increase the molar density of Cl-
close to the anode. It makes reactions at the anode surface easily, and the
available chlorine concentration will increase. The gradient of CAC resulting from d = 1.0 mm in Fig. 6 is smaller
than in other results. It may be considered that the bubbles generated by the reaction will reduce the contact
surface area between the liquid and electrode plates. As a result, the bubbles prevent a reaction between narrow
electrode plates. Higher generation of CAC is obtained at CNaCl = 50,000 mg/l in this experiment.
In the low CNaCl conditions, the range of CAC distribution is small compared to the highest CNaCl
conditions, as shown in Fig. 6. In this condition, Cl-
production may be small and Cl2 may react sufficiently in
each plate interval. As a result, CAC does not heavily depend on the plate interval in the lower CNaCl. On the other
hand, in the high CNaCl conditions, the difference obtained from d =1.0 mm to 3.0 mm is smaller than that of d =
3.0 mm to 5.0 mm. It may be considered for d = 1.0 mm that the bubbles created between the narrow parallel
plates fill up the reaction surface of the plates and prevent the reactions.
Table 2. Experimental results at a constant flow rate (Q = 0.0551 ml/s)
Electrode interval
d [mm]
Concentration of NaCl
CNaCl [mg/l]
Current density
Is [A/m2
]
Voltage
V [Vdc]
Concentration of available
chlorine
CAC [mg/l]
1.0
10,000 182 3.12 720
20,000 363 3.27 2,180
30,000 545 3.36 3,190
40,000 727 3.50 4,240
50,000 909 3.65 4,910
3.0
10,000 182 3.46 610
20,000 363 3.67 2,550
30,000 545 3.59 4,060
40,000 727 3.61 4,660
50,000 909 3.75 6,040
5.0
10,000 182 3.65 680
20,000 363 3.83 3,120
30,000 545 3.89 4,290
40,000 727 3.98 5,710
50,000 909 4.03 6,840
0
2,000
4,000
6,000
8,000
10,000
0 20,000 40,000 60,000
NaCl concentration CNaCl [mg/l]
Concentrationofavailable
chlorineCAC[mg/l]
1.0 mm
3.0 mm
5.0 mm
Electrode plate interval
0
2,000
4,000
6,000
8,000
10,000
0 20,000 40,000 60,000
NaCl concentration CNaCl [mg/l]
Concentrationofavailable
chlorineCAC[mg/l]
1.0 mm
3.0 mm
5.0 mm
Electrode plate interval
Figure 6. Concentration of available chlorine ( Q = 0.0551 ml/s)
4.4 Dependence of current density
Current density supplied to the electrode plate is varied. However, the flow rate is fixed at Q = 0.0551
ml/s, and the NaCl concentrations of the medium chosen here are CNaCl = 30,000, 40,000 and 50,000 mg/l,
because higher concentration production of the available chlorine were achieved in these conditions during the
preliminary experiment.
The experimental results are shown in Table 3 and Fig. 7. The concentration of available chlorine CAC
increases as the current density increases. The mobility of ions and electrons become active as the current
density increases. Here, the mobility of Cl-
becomes active and the reaction of Cl-
increases. As a result, CAC
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increases as the current density increases. On the other hand, the mobility of Cl-
becomes slower when the
current density is smaller. In this case, the electron will be consumed in the H2O reducing reaction. The fluid
temperature between the electrode plates rises with higher current densities and HClO will be decomposed at
just over 44 ºC. A higher CAC was obtained at Is = 800 A/m2
in this experiment.
Table 3. Experimental results at several current densities (Q = 0.0551 ml/s)
Electrode interval
d [mm]
Concentration of NaCl
CNaCl [mg/l]
Current density
Is [A/m2
]
Voltage
V [Vdc]
Concentration of available
chlorine
CAC [mg/l]
1.0
30,000
200 3.04 1,960
400 3.26 3,260
600 3.45 3,590
800 3.60 4,060
40,000
200 2.65 2,000
400 3.18 3,490
600 3.40 3,920
800 3.59 4,590
50,000
200 2.96 2,280
400 3.19 3,380
600 3.34 3,840
800 3.51 4,460
3.0
30,000
200 3.03 1,390
400 3.34 3,030
600 3.65 3,790
800 3.87 4,770
40,000
200 2.55 2,700
400 3.35 3,700
600 3.57 5,210
800 3.78 5,540
50,000
200 2.56 3,080
400 3.27 4,120
600 3.53 5,180
800 3.70 6,280
5.0
30,000
200 3.24 2,240
400 3.68 3,960
600 3.97 4,690
800 4.22 5,200
40,000
200 3.11 2,910
400 3.58 4,700
600 3.82 5,340
800 4.00 6,450
50,000
200 2.64 3,150
400 3.44 4,540
600 3.75 5,830
800 3.93 6,840
0
2,000
4,000
6,000
8,000
10,000
0 200 400 600 800 1,000
Current density Is [A/m2]
Concentrationofavailable
chlorineCAC[mg/l]
30,000 40,000 50,000 mg/l
mm
1.0
3.0
5.0
0
2,000
4,000
6,000
8,000
10,000
0 200 400 600 800 1,000
Current density Is [A/m2]
Concentrationofavailable
chlorineCAC[mg/l]
30,000 40,000 50,000 mg/l
mm
1.0
3.0
5.0
30,000 40,000 50,000 mg/l
mm
1.0
3.0
5.0
Figure 7. Concentration of available chlorine versus current density ( Q = 0.0551 ml/s)
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4.5 Dependence of solution flow rate
The flow rate of the NaCl solution is varied and the NaCl concentration is fixed at CNaCl = 50,000 mg/l.
Current densities are set at Is = 600 and 800 A/m2
in order to achieve a sufficient reaction. The results are shown
in Table 4 and Fig. 8. The concentration of available chlorine CAC decreases as the flow rate increases. As the
flow rate increases, the volume flow rate of H2O increased and the reaction of Cl2 on the electrode plate is
reduced because Cl2 has fewer chances to undergo the desired reaction. As a result, Cl2 does not sufficiently
dissolve into H2O and then flows out. In order to produce a high concentration of available chlorine, a lower
flow rate may be desired.
Table 4. Experimental results at several flow rates (CNaCl = 50,000 mg/l)
Electrode interval
d [mm]
Flow rate
Q [ml/s]
Current density
Is [A/m2
]
Voltage
V [Vdc]
Concentration of available
chlorine
CAC [mg/l]
1.0
0.0358
600
3.31 4,620
0.0551 3.34 3,840
0.0775 3.40 3,800
0.1140 3.41 3,080
0.0358
800
3.47 5,220
0.0551 3.51 4,460
0.0775 3.58 4,630
0.1140 3.56 3,390
3.0
0.0358
600
3.51 5,100
0.0551 3.53 5,180
0.0775 3.61 4,540
0.1140 3.61 4,010
0.0358
800
3.66 6,640
0.0551 3.70 6,280
0.0775 3.75 5,520
0.1140 3.82 4,870
5.0
0.0358
600
3.74 6,070
0.0551 3.75 5,830
0.0775 3.77 5,220
0.1140 3.79 4,390
0.0358
800
3.87 7,030
0.0551 3.93 6,840
0.0775 3.98 6,010
0.1140 4.01 5,140
0
2,000
4,000
6,000
8,000
10,000
0.00 0.02 0.04 0.06 0.08 0.10 0.12
Concentrationofavailable
chlorineCAC[mg/l]
600 800 A/m2
mm
1.0
3.0
5.0
Flow rate [ml/s]Q
0
2,000
4,000
6,000
8,000
10,000
0.00 0.02 0.04 0.06 0.08 0.10 0.12
Concentrationofavailable
chlorineCAC[mg/l]
600 800 A/m2
mm
1.0
3.0
5.0
600 800 A/m2
mm
1.0
3.0
5.0
Flow rate [ml/s]QFlow rate [ml/s]Q
Figure 8. Concentration of available chlorine versus flow rate (CNaCl = 50,000 mg/l)
4.6 Dependence of electrode plate interval
Gas and liquid two-phase flow in the narrow and parallel flat plates has very complex flow
characteristics. Especially, the generated gas in the flow field may fill up the narrow space and prevent further
reactions. The concentration of available chlorine, CAC, increases as the plate interval increases, as shown in
Figs. 6-8. As the plate interval increases, the liquid has a chance to make contact with the electrode plates
without small bubbles, and the flow velocity becomes low for a constant volume flow rate. In this case, the
reaction time of the NaCl solution increases. As a result, Cl2 is easy to dissolve into the solution at low flow
velocity, and thus CAC increases.
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4.7 Overall evaluation for high-concentration production
In this experiment, the effects of the experimental parameters on the concentration of available chlorine,
CAC, are examined. Geometrical influence and flow conditions are considered as experimental parameters in this
experiment. The electrode plate interval is varied for the first mentioned of the two, and the flow rate, current
density and NaCl concentration of the solution are varied for the latter. However, the overall evaluation is very
important for an actual device design. An experimental design is introduced in this evaluation [29, 30]. This
method clarifies the respective importance of each parameter. Table 5 shows the results estimated using an
experimental design method for an obtained CAC mentioned above. As a result, current density strongly
contributes to CAC production. These results agree well with the experimental results mentioned above.
Table 5. Contribution of parameters to the formation of available chlorine
Factor Rate of contribution [%]
Current density Is 56.6
Flow rate Q 2.7
Concentration of NaCl CNaCl 23.2
Error 17.5
Total 100.0
V. CONCLUSION
The high concentration production of available chlorine is investigated experimentally using a narrow
and parallel electrode plates without a barrier membrane. The flow between the plates is gas and liquid two-
phase flow, and the bubbles in the flow field prevented the chemical reaction. In this experiment, the NaCl
concentration of the solution, current density supplied to the electrode, electrode plate interval and volume flow
rate are all taken into account as experimental parameters. The high concentration production of CAC is affected
strongly by the current density and the NaCl concentration. However, bubbles between the electrode plates
prevent the chemical reaction. These results will be useful to produce chlorinated water, called hypochlorous
acid water, with a high efficiency, too.
Nomenclature
C = Concentration [mg/l]
d = Electrode plate interval [mm]
F = Faraday constant (9.65x104
C/mol)
G = Standard Gibbs energy of formation [J/mol]
I = Current density [A/m2
]
K = Dissociation constant [mol/l]
M = Molecular weight [g/mol]
n = Electron count [-]
Q = Volume flow rate [ml/s]
S = Reaction area [m2
]
V = Voltage [V]
V = Electric potential difference [V]
Subscripts
AC = Available chlorine
NaCl = Sodium chloride
s = Electrode surface
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