The radiolytic mineralization of 2-mercaptobenzothiazole, an emerging contami...IRJESJOURNAL
Abstract:The ability of high-energy ionizing radiation has been demonstrated for environmental remediation processing. γ-rayswere applied to treat a solution of 2-mercaptobenzothiazole (2-MBT). 2-MBT (125 µM) was decomposed and mineralized by the γ-radiation. The absorbed doses for 50 and 90% 2-MBT degradation were 0.170 and 0.650 kGy, respectively. Organic by-products were almost fully mineralized when high-absorbed doses in the range of 5-60 kGy were applied. Sulfate radicals (SO4 ●– ) produced through the rapid reaction of persulfate ions (S2O8 2– ) with hydrated electrons(eaq − ; keaq − /S2O8 2– = 1.1 × 1010 M −1 .s−1 ) had a significant effect on the 2-MBT mineralization yield. Because of 2-MBT decomposition,sulfate ions (SO4 2− ) were formed, and thepH and dissolved oxygen concentration were decreased. The degradation efficiency decreased when HCO3 –was added to the 2- MBT solution. No significant effects of NO3 – and Cl– ions on 2-MBT radiolytic eliminationwere observed
COD reduction of aromatic polluted waste water by Advanced Oxidation Process ...Wade Bitaraf
In most petrochemical complexes and oil refineries the wastewater contains the aromatic compounds among which Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) have harmful effects on environment and human health. The present work mainly deals with the UV-based advanced oxidation processes (AOPs), UV/H2O2 were tested in batch reactor systems to evaluate the removal efficiencies and optimal conditions for the photodegradation of BTEX in order to wastewater treatment. The efficiency of this method was analyzed by evaluating the Chemical Oxygen Demand (COD) as a pollution criterion through the COD reactor. The influence of the basic operational parameters such as initial concentration of H2O2, pH, Temperature, irradiation time and UV amount on the photo degradation of BTEX were also studied. The oxidation rate of BTEX and respectively the reduction rate of COD were low when the oxidation was carried out in the absence of H2O2 or UV light. The addition of proper amount of hydrogen peroxide improved the degradation, while the excess hydrogen peroxide could quench the formation of hydroxyl radicals (•OH). The optimal conditions of suspended slurry with 1.11(g/l) initial concentration of H2O2 and pH value of 3.1 were obtained under three UV lights illumination (6 W). Under the optimal conditions, COD reduction during the initial period of 180 min in UV/H2O2 systems reached about 90%.
A Review on Applicability of Photocatalyst Titanium dioxide for Treatment of ...IJERA Editor
Greywater reuse has attracted great attention for sustainable management of water especially under water
scarcity conditions. However, the effort has been limited by the presence of toxic organics in the effluent which
in turn inhibits the public acceptance of recycling water. The existence of those organic pollutants, which cannot
be eliminated by conventional primary and secondary treatment processes, can be problematic. Hence it is
necessary to explore a sustainable, robust and affordable method for treatment of greywater. Photocatalytic
oxidation is an emerging technology that could be suitable to remove refractory organic compounds found in
greywater. Recently titanium dioxide (TiO2) gained wide attention for photocatalytic oxidation of organic matter
of wastewater. Because it is biologically and chemical inert, resistant to chemical corrosion and can work at
ambient temperature and pressure, without addition of chemical species. The irradiation of titanium dioxide
dispersions by ultraviolet (UV) (300-400 nm) light can lead to the formulation of highly reactive hydroxyl
radicals which attack the pollutant molecule to degrade it into carbon dioxide, water and mineral acids.This
technology has advantages, such as, the integration into small places, low maintenance and easy operation.
The radiolytic mineralization of 2-mercaptobenzothiazole, an emerging contami...IRJESJOURNAL
Abstract:The ability of high-energy ionizing radiation has been demonstrated for environmental remediation processing. γ-rayswere applied to treat a solution of 2-mercaptobenzothiazole (2-MBT). 2-MBT (125 µM) was decomposed and mineralized by the γ-radiation. The absorbed doses for 50 and 90% 2-MBT degradation were 0.170 and 0.650 kGy, respectively. Organic by-products were almost fully mineralized when high-absorbed doses in the range of 5-60 kGy were applied. Sulfate radicals (SO4 ●– ) produced through the rapid reaction of persulfate ions (S2O8 2– ) with hydrated electrons(eaq − ; keaq − /S2O8 2– = 1.1 × 1010 M −1 .s−1 ) had a significant effect on the 2-MBT mineralization yield. Because of 2-MBT decomposition,sulfate ions (SO4 2− ) were formed, and thepH and dissolved oxygen concentration were decreased. The degradation efficiency decreased when HCO3 –was added to the 2- MBT solution. No significant effects of NO3 – and Cl– ions on 2-MBT radiolytic eliminationwere observed
COD reduction of aromatic polluted waste water by Advanced Oxidation Process ...Wade Bitaraf
In most petrochemical complexes and oil refineries the wastewater contains the aromatic compounds among which Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) have harmful effects on environment and human health. The present work mainly deals with the UV-based advanced oxidation processes (AOPs), UV/H2O2 were tested in batch reactor systems to evaluate the removal efficiencies and optimal conditions for the photodegradation of BTEX in order to wastewater treatment. The efficiency of this method was analyzed by evaluating the Chemical Oxygen Demand (COD) as a pollution criterion through the COD reactor. The influence of the basic operational parameters such as initial concentration of H2O2, pH, Temperature, irradiation time and UV amount on the photo degradation of BTEX were also studied. The oxidation rate of BTEX and respectively the reduction rate of COD were low when the oxidation was carried out in the absence of H2O2 or UV light. The addition of proper amount of hydrogen peroxide improved the degradation, while the excess hydrogen peroxide could quench the formation of hydroxyl radicals (•OH). The optimal conditions of suspended slurry with 1.11(g/l) initial concentration of H2O2 and pH value of 3.1 were obtained under three UV lights illumination (6 W). Under the optimal conditions, COD reduction during the initial period of 180 min in UV/H2O2 systems reached about 90%.
A Review on Applicability of Photocatalyst Titanium dioxide for Treatment of ...IJERA Editor
Greywater reuse has attracted great attention for sustainable management of water especially under water
scarcity conditions. However, the effort has been limited by the presence of toxic organics in the effluent which
in turn inhibits the public acceptance of recycling water. The existence of those organic pollutants, which cannot
be eliminated by conventional primary and secondary treatment processes, can be problematic. Hence it is
necessary to explore a sustainable, robust and affordable method for treatment of greywater. Photocatalytic
oxidation is an emerging technology that could be suitable to remove refractory organic compounds found in
greywater. Recently titanium dioxide (TiO2) gained wide attention for photocatalytic oxidation of organic matter
of wastewater. Because it is biologically and chemical inert, resistant to chemical corrosion and can work at
ambient temperature and pressure, without addition of chemical species. The irradiation of titanium dioxide
dispersions by ultraviolet (UV) (300-400 nm) light can lead to the formulation of highly reactive hydroxyl
radicals which attack the pollutant molecule to degrade it into carbon dioxide, water and mineral acids.This
technology has advantages, such as, the integration into small places, low maintenance and easy operation.
Visible light solar photocatalytic degradation of pulp and paper wastewater u...eSAT Journals
Abstract
With the growing number of industries there are large volumes of wastewater generated every day. Pulp and paper mills are highly polluting as they release effluents containing organic pollutants, and high levels of Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Even though well-established processes exist to treat these effluents, there are only a few processes which are energy efficient. Conventional treatment methods are not effective for the degradation of toxic organic pollutants, hence other treatment techniques are necessary. One of the recent developments in this field is the Advanced Oxidation Process (AOP). Solar photocatalysis is a type of AOP which utilises UV light to activate semiconductor photocatalyst in order to produce highly reactive radical species. TiO2 is a widely used catalyst for this purpose, to oxidise or reduce the organic pollutants in industrial wastewater. However, photocatalysis using visible light has been receiving increased attention hence, modification of TiO2 is necessary for its enhanced response to visible light. There are many methods for modifying TiO2, such as doping and photo-sensitisation. This study focusses on the modification of TiO2 using the method of dye-sensitisation (photo-sensitisation) with the dyes rhodamine B and methylene blue. Solar photocatalytic experiments were carried out for the degradation of pulp and paper wastewater, at different conditions like varying catalyst loading (500mg, 600mg, 750mg and 1000mg of catalyst for 300ml of aqueous wastewater) and effluent concentration (20ml, 25ml, 30ml and 35ml of wastewater). Preliminary tests were done to determine the best conditions for photocatalytic degradation, and these were applied for final tests. Keywords - Solar Photocatalysis, Visible Light, Dye Sensitisation, Pulp and paper, Methylene blue, Rhodamine B, TiO2 catalyst.
Removal of Heavy Metals from Aqueous Solution Using Ion Exchange Resin MBHPE-TKPijsrd.com
The aim of this study is to synthesis of TKP (MBHPE-TKP) resin for the removal of heavy metals from aqueous solution. Ion exchange resins are polymers that are capable of exchanging particular ions within the polymer with ions in a solution that is passed through them. This ability is also seen in various natural systems such as soils and living cells. The synthetic resins are used primarily for purifying water, but also for various other applications including separating out some elements. Factorial design of experiments is employed to study the effect of above factors pH, time and sorbent used. The new synthesized resins i.e. MBHPE–TKP is hydrophilic and biodegradable, so after effluent treatment used resins can be disposed off without facing any environmental problem .This study focuses on synthesis of new cation exchange resin (MBHPE – TKP) and developing method for treatment of highly contaminated industrial effluents.
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...Dr. Md. Aminul Islam
Ni(II) polluted water becomes a significant issue in recent years. Excessive levels of Ni(II) are detrimental to the plant, animal and human life, so it is important to reduce the amount of Ni(II) that enters the environment from polluted water. Manganese oxides, found in soils are important in determining the availability of Ni(II) in soil systems as they absorb Ni(II) onto their surface. Therefore, they may be able to be used to remove Ni(II) from wastewater so it is important to understand the interaction mechanisms of Ni(II) with manganese- containing minerals. As a consequence, Ni(II) adsorption onto birnessite, pyrolusite, hausmannite, manganite, boehmite, and Mn-Al binary oxide were investigated as a function of solution pH using an initial Ni(II) concentration in 1 mM NaNO 3 solution at 22 ± 2 °C. The adsorption data were modeled using Langmuir, Freundlich and extended constant capacitance model (ECCM) approach to predict the possible adsorption reactions. The accumulation process was strongly dependent on pH, initial Ni(II) concentration, and the nature of the mineral. The position of adsorption edges (pH 50 ) varied significantly between the minerals investigated. Birnessite exhibited maximum Ni(II) uptake, while pyrolusite exhibited minimum uptake. The Langmuir equation provided a reasonable correlation of data. ECCM results indicate that Ni(II) formed outer-sphere complexes at low pH, and inner- sphere complexes and surface precipitation at higher pH. Proton stoichiometry suggests that more than one reaction involved in the overall Ni(II) adsorption process. This study on Mn- oxides as sorbents for Ni(II) demonstrates that MnOs may be effective in removing Ni(II) pollutants from wastewater.
Efficiency of Carbonate Precipitation and Removal of Copper and Nickel Ions f...AnuragSingh1049
The effect of pH and initial concentration on the removal of Cu(II) and Ni(II) ions from their monocomponent and two-component aqueous solutions using Na2CO3 as a chemical precipitation agent was investigated in this paper. Monocomponent aqueous solutions of Cu(II) and Ni(II) ions with their initial concentrations of 50 and 500 mg/L and two-component aqueous solution with initial concentration of 500 mg/L were prepared. The precipitation was carried out by batch method at room temperature by stirring the solution at 300 rpm for 5 minutes, resulting in the formation of precipitates. The resulting precipitate was separated by filtration from the solution. The experiment proved that Na2CO3 is a good agent for removing Cu(II) and Ni(II) ions from their monocomponent water solutions of 50 and 500 mg/L concentration and two-component water solution with initial concentration of each metal 500 mg/L. The percentage of Cu(II) removal was higher at lower pH values compared to Ni(II) removal.
degradation of pollution and photocatalysisPraveen Vaidya
The presentation deals with the use of conduction of photocatalytic reaction using the transition metal doped transparent semiconducting thinfilms. The precursor to film is prepared by the SILAR method, which is a chemical method.
Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solu...ijtsrd
The removal of heavy metals from industrial wastewater is of great concern as heavy metals are non-biodegradable, toxic elements that cause serious health problems if disposed of in the surrounding environment. The present study, Karisalangkani (Eclipta Alba) leaves were used for the adsorption of heavy metals like copper (Cu (II)) ions. The bio sorbent was characterized using SEM and BET analysis. The bio sorption experiments are conducted through batch system. The operating parameters studied were initial metal ion concentration, adsorbent dosage, initial solution pH, contact time and effect of temperature Adsorption equilibrium is achieved in 30 min and the adsorption kinetics of Cu (II) is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu (II) adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu (II) ions is estimated to be 9.2 mgg at 25 °C. The experimental result shows that the materials have good potential to remove heavy metals from effluent and good potential as an alternate low cost adsorbent. Due to their outstanding adsorption capacities, Eclipta Alba is excellent sorbents for the removal of copper (II) ions. B. Kavitha | R. Arunadevi"Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17156.pdf http://www.ijtsrd.com/chemistry/environmental-chemistry/17156/biosorption-of-copper-ii-ions-by-eclipta-alba-leaf-powder-from-aqueous-solutions/b-kavitha
PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT...IAEME Publication
The present work aims to degrade the RB21 dye from synthetic wastewater using
semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was
carried out using different light sources of 900 W/m
2
intensity in natural sunlight from 02:00 to
04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave
oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the
experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room
temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at
different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD
degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic
reactor using TiO2. The successful result obtained using TiO2is 80% COD
degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO.
Chemical kinetics was found to follow first order mechanism. The formation of intermediate
compounds and identification of the final products were carried out using LCMS/MS analysis and
FT-IR techniques.
Kinetics and Thermodynamic Studies of Biosorption of Cadmium (ii) from Aqueous Solution onto Garden Grass (GAG)
Original Research Article
Journal of Chemistry and Materials Research Vol. 1 (1), 2014, 12–22
B.O. Evbuomwan, M.M. Atuka
EDTA-enhanced phytoextraction of Cd and Pb in spiked soil with Marigold and a...Agriculture Journal IJOEAR
Abstract— EDTA is a common chelating agent used in phytoextraction for enhancing the trace elements uptake from soil to plants. But application of EDTA can cause ground water contamination, which is potentially a risk for human health. In this study EDTA-enhanced phytoextraction of Cd and Pb by Marigold. was evaluated. Application of EDTA could significantly increase Cd and Pb accumulation in the various part of plants, but EDTA addition also increased the Cd and Pb concentration in leached water about 8 to 12 time and 50 to 75 times respectively compared to the control. So, insitu application of EDTA can be potentially risk to ground water contamination with trace elements.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
Applicability of Fenton Process for Treatment of Industrial Effluents: A ReviewIJERA Editor
Wastewater and effluent treatment has undergone innovative changes over the years. Traditional wastewater treatment has yielded to modern and path-breaking procedures which are more efficient and effective. The world of difficulties and unknown has opened new avenues and paths to highly feasible effluent treatment procedures, so the vigorous importance of advanced oxidation procedures. This review paper will delineate the increasing importance of various advanced oxidation processes including Fenton treatment for wastewater. Advanced oxidation processes (AOP’s), which involve and includes the in-situ generation of highly potent chemical oxidants such as the hydroxyl radical, have emerged as an important avenue of technologies to accelerate the non-selective oxidation and thus the destruction of a wide range of non-degradable organic contaminants in wastewater which cannot be eliminated biologically. Advanced oxidation processes (AOP) are technologies based on the generation of highly reactive species, the hydroxyl radicals, used in oxidative degradation procedures for organic compounds dissolved or dispersed in aquatic media. These processes are promising alternatives for decontamination of media containing dissolved recalcitrant organic substances, which would not be efficiently removed by conventional methods.
Visible light solar photocatalytic degradation of pulp and paper wastewater u...eSAT Journals
Abstract
With the growing number of industries there are large volumes of wastewater generated every day. Pulp and paper mills are highly polluting as they release effluents containing organic pollutants, and high levels of Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Even though well-established processes exist to treat these effluents, there are only a few processes which are energy efficient. Conventional treatment methods are not effective for the degradation of toxic organic pollutants, hence other treatment techniques are necessary. One of the recent developments in this field is the Advanced Oxidation Process (AOP). Solar photocatalysis is a type of AOP which utilises UV light to activate semiconductor photocatalyst in order to produce highly reactive radical species. TiO2 is a widely used catalyst for this purpose, to oxidise or reduce the organic pollutants in industrial wastewater. However, photocatalysis using visible light has been receiving increased attention hence, modification of TiO2 is necessary for its enhanced response to visible light. There are many methods for modifying TiO2, such as doping and photo-sensitisation. This study focusses on the modification of TiO2 using the method of dye-sensitisation (photo-sensitisation) with the dyes rhodamine B and methylene blue. Solar photocatalytic experiments were carried out for the degradation of pulp and paper wastewater, at different conditions like varying catalyst loading (500mg, 600mg, 750mg and 1000mg of catalyst for 300ml of aqueous wastewater) and effluent concentration (20ml, 25ml, 30ml and 35ml of wastewater). Preliminary tests were done to determine the best conditions for photocatalytic degradation, and these were applied for final tests. Keywords - Solar Photocatalysis, Visible Light, Dye Sensitisation, Pulp and paper, Methylene blue, Rhodamine B, TiO2 catalyst.
Removal of Heavy Metals from Aqueous Solution Using Ion Exchange Resin MBHPE-TKPijsrd.com
The aim of this study is to synthesis of TKP (MBHPE-TKP) resin for the removal of heavy metals from aqueous solution. Ion exchange resins are polymers that are capable of exchanging particular ions within the polymer with ions in a solution that is passed through them. This ability is also seen in various natural systems such as soils and living cells. The synthetic resins are used primarily for purifying water, but also for various other applications including separating out some elements. Factorial design of experiments is employed to study the effect of above factors pH, time and sorbent used. The new synthesized resins i.e. MBHPE–TKP is hydrophilic and biodegradable, so after effluent treatment used resins can be disposed off without facing any environmental problem .This study focuses on synthesis of new cation exchange resin (MBHPE – TKP) and developing method for treatment of highly contaminated industrial effluents.
Macroscopic and modeling evidence for nickel(II) adsorption onto selected man...Dr. Md. Aminul Islam
Ni(II) polluted water becomes a significant issue in recent years. Excessive levels of Ni(II) are detrimental to the plant, animal and human life, so it is important to reduce the amount of Ni(II) that enters the environment from polluted water. Manganese oxides, found in soils are important in determining the availability of Ni(II) in soil systems as they absorb Ni(II) onto their surface. Therefore, they may be able to be used to remove Ni(II) from wastewater so it is important to understand the interaction mechanisms of Ni(II) with manganese- containing minerals. As a consequence, Ni(II) adsorption onto birnessite, pyrolusite, hausmannite, manganite, boehmite, and Mn-Al binary oxide were investigated as a function of solution pH using an initial Ni(II) concentration in 1 mM NaNO 3 solution at 22 ± 2 °C. The adsorption data were modeled using Langmuir, Freundlich and extended constant capacitance model (ECCM) approach to predict the possible adsorption reactions. The accumulation process was strongly dependent on pH, initial Ni(II) concentration, and the nature of the mineral. The position of adsorption edges (pH 50 ) varied significantly between the minerals investigated. Birnessite exhibited maximum Ni(II) uptake, while pyrolusite exhibited minimum uptake. The Langmuir equation provided a reasonable correlation of data. ECCM results indicate that Ni(II) formed outer-sphere complexes at low pH, and inner- sphere complexes and surface precipitation at higher pH. Proton stoichiometry suggests that more than one reaction involved in the overall Ni(II) adsorption process. This study on Mn- oxides as sorbents for Ni(II) demonstrates that MnOs may be effective in removing Ni(II) pollutants from wastewater.
Efficiency of Carbonate Precipitation and Removal of Copper and Nickel Ions f...AnuragSingh1049
The effect of pH and initial concentration on the removal of Cu(II) and Ni(II) ions from their monocomponent and two-component aqueous solutions using Na2CO3 as a chemical precipitation agent was investigated in this paper. Monocomponent aqueous solutions of Cu(II) and Ni(II) ions with their initial concentrations of 50 and 500 mg/L and two-component aqueous solution with initial concentration of 500 mg/L were prepared. The precipitation was carried out by batch method at room temperature by stirring the solution at 300 rpm for 5 minutes, resulting in the formation of precipitates. The resulting precipitate was separated by filtration from the solution. The experiment proved that Na2CO3 is a good agent for removing Cu(II) and Ni(II) ions from their monocomponent water solutions of 50 and 500 mg/L concentration and two-component water solution with initial concentration of each metal 500 mg/L. The percentage of Cu(II) removal was higher at lower pH values compared to Ni(II) removal.
degradation of pollution and photocatalysisPraveen Vaidya
The presentation deals with the use of conduction of photocatalytic reaction using the transition metal doped transparent semiconducting thinfilms. The precursor to film is prepared by the SILAR method, which is a chemical method.
Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solu...ijtsrd
The removal of heavy metals from industrial wastewater is of great concern as heavy metals are non-biodegradable, toxic elements that cause serious health problems if disposed of in the surrounding environment. The present study, Karisalangkani (Eclipta Alba) leaves were used for the adsorption of heavy metals like copper (Cu (II)) ions. The bio sorbent was characterized using SEM and BET analysis. The bio sorption experiments are conducted through batch system. The operating parameters studied were initial metal ion concentration, adsorbent dosage, initial solution pH, contact time and effect of temperature Adsorption equilibrium is achieved in 30 min and the adsorption kinetics of Cu (II) is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu (II) adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu (II) ions is estimated to be 9.2 mgg at 25 °C. The experimental result shows that the materials have good potential to remove heavy metals from effluent and good potential as an alternate low cost adsorbent. Due to their outstanding adsorption capacities, Eclipta Alba is excellent sorbents for the removal of copper (II) ions. B. Kavitha | R. Arunadevi"Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17156.pdf http://www.ijtsrd.com/chemistry/environmental-chemistry/17156/biosorption-of-copper-ii-ions-by-eclipta-alba-leaf-powder-from-aqueous-solutions/b-kavitha
PHOTOCATALYTIC DEGRADATION OF RB21 DYE BY TIO2 AND ZNO UNDER NATURAL SUNLIGHT...IAEME Publication
The present work aims to degrade the RB21 dye from synthetic wastewater using
semiconductors TiO2 and ZnO. The activity of photocatalytic degradation process of dye was
carried out using different light sources of 900 W/m
2
intensity in natural sunlight from 02:00 to
04:00 pm with 48°C temperature in Ahmedabad city in the month of May, 600 Watt microwave
oven and high pressure UV-light photocatalytic reactor of wavelength 200-450 nm. All the
experiments were performed with dye concentration 50 mg/L, catalyst dosage 0.8 g, pH 7, room
temperature, irradiation time 240 min followed by 30 min in dark. All the samples were collected at
different time intervals of 30, 60, 90, 120, 150, 180, 210, 240 min for the analysis of COD
degradation and color removal. The best performances was achieved using high pressure UVphotocatalytic
reactor using TiO2. The successful result obtained using TiO2is 80% COD
degradation and 99% color removal followed by 75% COD and 99% color removal with ZnO.
Chemical kinetics was found to follow first order mechanism. The formation of intermediate
compounds and identification of the final products were carried out using LCMS/MS analysis and
FT-IR techniques.
Kinetics and Thermodynamic Studies of Biosorption of Cadmium (ii) from Aqueous Solution onto Garden Grass (GAG)
Original Research Article
Journal of Chemistry and Materials Research Vol. 1 (1), 2014, 12–22
B.O. Evbuomwan, M.M. Atuka
EDTA-enhanced phytoextraction of Cd and Pb in spiked soil with Marigold and a...Agriculture Journal IJOEAR
Abstract— EDTA is a common chelating agent used in phytoextraction for enhancing the trace elements uptake from soil to plants. But application of EDTA can cause ground water contamination, which is potentially a risk for human health. In this study EDTA-enhanced phytoextraction of Cd and Pb by Marigold. was evaluated. Application of EDTA could significantly increase Cd and Pb accumulation in the various part of plants, but EDTA addition also increased the Cd and Pb concentration in leached water about 8 to 12 time and 50 to 75 times respectively compared to the control. So, insitu application of EDTA can be potentially risk to ground water contamination with trace elements.
Preparation, characterization and application of sonochemically doped fe3+ in...eSAT Journals
Abstract In this present study, mechanistic investigation of ultrasound–assisted dye decolorization/degradation was investigated using sonochemically prepared Fe3+ doped ZnO. Fe3+ doped ZnO nanoparticle was prepared under ultrasound (20 kHz) irradiation using a doping concentration of 2 wt% of Fe(III). To investigate the catalytic activity of Fe3+ doped ZnO, Acid Red 14 (azo dye) was chosen for decolorization/degradation using sonolysis, photocatalysis and sono–photocatalysis processes. To study the influence of dopant onto structure, crystallinity, and optical properties, different analytical analyses were performed such as X–ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Zeta potential, Delsa Nano Particle Size Analyzer (PSA), Vibrating Sample Magnetometer analysis (VSM) and Field Emission Scanning Electron Microscopy (FE–SEM) etc. For photocatalytic experiments, a blended high pressure mercury UV lamp with maximum peak emission at 365 nm was used. The decolorization/degradation of dye with modified photocatalyst showed faster reaction kinetics under sono–photocatalytic process. Ultrasound showed an additive effect for degradation/decolorization process. The maximum decolorization of AR14 was achieved (~ 82%) under sono–photocatlytic process with an initial dye concentration of 20 ppm. The sono–photocatalysis process showed 1.4 – 1.6 higher reaction rates with Fe–doped ZnO than pure ZnO. Index Terms: ZnO, Fe–ZnO, Fe-doped ZnO, Sonocatalytic, Photocatalytic, Advanced Oxidation Process, AOP
Applicability of Fenton Process for Treatment of Industrial Effluents: A ReviewIJERA Editor
Wastewater and effluent treatment has undergone innovative changes over the years. Traditional wastewater treatment has yielded to modern and path-breaking procedures which are more efficient and effective. The world of difficulties and unknown has opened new avenues and paths to highly feasible effluent treatment procedures, so the vigorous importance of advanced oxidation procedures. This review paper will delineate the increasing importance of various advanced oxidation processes including Fenton treatment for wastewater. Advanced oxidation processes (AOP’s), which involve and includes the in-situ generation of highly potent chemical oxidants such as the hydroxyl radical, have emerged as an important avenue of technologies to accelerate the non-selective oxidation and thus the destruction of a wide range of non-degradable organic contaminants in wastewater which cannot be eliminated biologically. Advanced oxidation processes (AOP) are technologies based on the generation of highly reactive species, the hydroxyl radicals, used in oxidative degradation procedures for organic compounds dissolved or dispersed in aquatic media. These processes are promising alternatives for decontamination of media containing dissolved recalcitrant organic substances, which would not be efficiently removed by conventional methods.
In the present scenario, water pollution caused by domestic, industrial, commercial, and
agricultural activities has emerged as one of the major environmental challenges in both
developed and developing countries. The consumption of available freshwater is almost
70%, 22%, and 8% in agricultural, industrial, and domestic sectors, respectively. The current
trend of a growing population might lead to an acute shortage of water and it is anticipated
that by the end of 2027, around four billion people will encounter the problem of clean
drinking water due to groundwater depletion and water pollution (Nemerow and
Dasgupta 1991; Helmer and Hespanhol 1997; Lehr and DeMarre 1980; Ali and Aboul-
Enein 2004; Murray et al. 2015). Freshwater is essential for the survival of life. River and
water resource contamination around the world is directly increasing due to rapid expansion
in population and urbanization, as well as the rapid pace of industrialization leading
to direct disposal of untreated noxious industrial waste, sanitary waste, and excess from
agricultural fields. The scarcity of freshwater and its treatment cost impose paying for clean
water and water tariffs in developing countries (Nemerrow 1978; Forgacs et al. 2004).
Wastewater contains several pollutants such as biological pollutants, undesirable inorganic
and organic chemicals that include heavy metal ions, dyes, and medication waste, which
makes water unsafe for drinking purposes. Treatment of this contaminated water is a large
challenge at present (Rai et al. 2005; Reddy and Yun 2016; Santhosh et al. 2016). These pollutants
are not only harmful to living beings but also directly affect the ecosystem. Hence,
removing these kinds of pollutants completely from wastewater or to reduce it to below a
certain level as per World Health Organization (WHO) guidelines is an urgent need to
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E-Waste: Recovery of Precious Materials and Minimization of Environmental Imp...CrimsonpublishersEAES
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A major treat to the comfort of human life has been imposed by the unintentional and great increased industrialization and urbanization. Their generations and land disposals of huge amounts of toxic materials and pollutants have contributed in contaminating our environment frighteningly. Synthetic dyes (SD) and heavy metals (HM) are becoming increasingly prevalent in soil and surface water environments, as the most dangerous pollutants. They are present a great concern worldwide, due to their toxicity to many life forms. Environment-friendly utilization of agricultural by-products/waste materials either as raw materials or in production of the so-called activated carbons (AC) is an important issue. Because, it is apparent from our literature review that the main factors characterizing these materials are the inexpensiveness, the local availability and their efficiencies in removal of heavy metals and dyes from contaminated water. A number of different agricultural by-product/wastes as renewable and potential sources for green adsorbent production has been listed in this review. Additionally, the paper has provided the reader with an overview of a number of case studies which were conducted by scientists and researchers. These case studies have pointed out to the efficient removal of SD/HM ions from aqueous solutions by the agricultural by-products/wastes in the form of a raw material, spent tea leaves (STL), spent coffee ground(SCG), and rice husk (RH) wastes were selected as a good examples. Besides, the efficient removal of such ions by AC produced from the same raw materials has been also reviewed. Both kinds are widely used adsorbents in the treatment of wastewaters. High adsorption capacity, cost effectiveness, and environmentally friendly, and their abundance in nature are the important factors which explain why the adsorbent materials derived from an agricultural by-product/wastes is economical for the removal of dye and metal ions from contaminated water. Comparison of different technologies of wastewater treatment especially heavy metals and dyes were also listed in this review
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State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
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Attacks on counties – USA
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In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
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Cyber risk predictions
Axis of attacks – Europe
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1. Innovative Systems Design and Engineering www.iiste.org
ISSN 2222-1727 (Paper) ISSN 2222-2871 (Online)
Vol 2, No 5, 2011
Solar photo catalytic degradation of environmental
contaminants
Chavan B. L.
Department of Environmental Science,
Dr.B.A.M.University, Aurangabad-431004 (India).
E-mail: drblchavan@yahoo.co.in
Abstract
Solar energy has been proved as an innovative and promising route for the treatment of
industrial effluents, waste water and for the purification of water. The solar detoxification
process has challenged the effectiveness of conventional treatment processes for the
degradation of environmental contaminants. The literature review of scientific and
technological aspects on solar photo catalytic degradation and detoxification process has
been conducted and briefly represented in the present paper.
Key words: Solar detoxification, effluent, metal oxide, photo-catalysis, spent wash.
Introduction:
The major environmental problem faced today is the continuous discharge of industrial
effluents and sewage into inland surface water. At present, unit treatment processes and
unit operations are grouped under primary, secondary and tertiary treatments. These
processes are energy intensive treat the effluent partially. Therefore, tertiary treatments
involving physical, chemical and biological process are employed. The photo-chemical
treatment is most advisable among these.
Photochemical Reactions:
The photochemical processes are useful for industrial units like effluents from distilleries,
pesticide industries, paper mills, pharmaceutical companies and chemical industries, but
are in developing stage. The oxidation and reduction reactions are the basic mechanisms
in photo catalytic treatment of water/air in their remediation and photo catalytic hydrogen
production. A simplified mechanism for photo catalytic process on a semiconductor is
presented in equation 1.
Photo catalyst (e.g., TiO2) + hv = eCB + hVB ----------------------------- (1)
For photo catalytic water/air remediation as an environmental application, valence band
(VB) holes are the important elements. These induce the oxidative decomposition of
environmental pollutants in which the positive hole can oxidize pollutants directly, but
mostly reacting with water constituent like hydroxide ion, (OH–) to produce the hydroxyl
radical (•OH), which is the very powerful oxidant with the oxidation potential of 2.8 V.
This •OH rapidly attacks pollutants at the surface of semi-conducting material and in
solution as well and can mineralize them into CO2, H2O, etc. The photo catalysts have a
potential to completely oxidize a variety of organic compounds, including many highly
persistent organic pollutants. The reducing conduction band (CB) electrons are more
important when photo catalytic reaction is applied for hydrogen production in water
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Vol 2, No 5, 2011
splitting. In order to initiate hydrogen production, the conduction band level must be
more negative than the hydrogen production level. These reactions are as follows:
2H2O → 2H2 + O2 -------------------------------------------------------(2)
H2O ↔ H+ + OH– -------------------------------------------------------(3)
2H2O + 2e– → H2 + 2OH– ------------------------------------------------(4)
2H2O → O2 + 4H+ + 4e– ------------------------------------------------(5)
Theoretical redox potential for overall reaction (eq. 2) at pH 7 is EH = -1.23 V, with the
corresponding half-reactions of -0.41 V (eq 4) and 0.82 V (eq 5). It, gives a Gibbs energy
(Go) = +237 kJ/mole (Li et al., 2000). A large number of metal oxides and sulfides are
primarily active under UV irradiation having wavelength < 385 nm or electron band gap
(Ebg) energy =3.0 eV which is present in only a small portion of solar light (Vinodgopal
et al., 1994; Li et al., 2000). For example, TiO2 has a wide band-gap energy of 3.0 ~ 3.2
eV. It prevents the utilization of visible-light that accounts for most of solar energy. More
recently, significant efforts have also been made to develop new or modified
semiconductor photo catalysts which are capable of using visible-light (wavelength 400–
700 nm) including metal ion doping, nonmetallic element doping, and sensitization with
organic dyes or small band-gap semiconductors like CdS, MgO and CaO. There is no
general rule at all, each case being completely different (Goslich et al., 1997, Malato et
al., 2002).
Solar photo catalytic degradation of contaminants
In general, the types of polluting compounds that have been degraded include alkanes,
halo alkanes, aliphatic alcohols, carboxylic acids, aromatics, halo aromatics, polymers,
surfactants, herbicides, pesticides, and dyes (Malato et al., 2003).
The photo catalysis mineralizing the contaminants into carbon dioxide, water, and
inorganic, practical applications of solar technologies have been studied and developed
most intensively for heterogeneous TiO2 or ZnO photo catalysis. There is no general rule
at all, each case being completely different than another (Goslich et al., 1997, Malato et
al., 2002). In general, the types of compounds or contaminants that have been degraded
include alkanes, haloalkanes, aliphatic alcohols, carboxylic acids, alkenes, aromatics,
halo aromatics, polymers, surfactants, herbicides, pesticides, and dyes (Malato et al.,
2003). The review of literature (Bahnemann et al., 1991; Chiou et al., 2008; Okamoto et
al., 1985; Rincn and Pulgarin, 2003; Topalov et al., 2000) reveals that much work
appears on the photo-catalytic activity of TiO2 for the removal of salts, color and other
organic and inorganic impurities and almost no systematic work is conducted on the other
photo-catalytic materials like MgO, ZnO and CaO.
Potential application of solar detoxification:
Since 1972, when Fujishima and Honda discovered the photo-catalytic splitting of water
molecules using TiO2 electrodes, research on the heterogeneous photo-catalysis started
growing rapidly. The applications have been directed towards environmental cleanup.
The other applications of the technique have been implemented in many fields such as,
drinking water treatments, industrial effluent treatments or health applications. Some of
these are as follows:
1. Destruction of organics:
Photo-catalysis has been used for the destruction of variety of organic compounds such as
alcohols, carboxylic acids, phenol derivatives or chlorinated aromatic into harmless or
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3. Innovative Systems Design and Engineering www.iiste.org
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Vol 2, No 5, 2011
least harmful products like CO2, H2O and simple minerals acids (Balasaraswathy, 2004;
Huang, 1991; Mehos and Turchi, 1992; Turchi et al., 1993; Wyness, 1994). Water
contaminated by oil can be treated efficiently by photo-catalytic reactions (Canela, 1999).
Herbicides and pesticides such as 2, 4, 5trichlorophenol, 5-triazine herbicides and DDT
which contaminate the water can be also mineralized (Alfano et al., 2000).
2. Removing trace metals:
Trace metal such as (Hg), chromium (Cr), lead (Pb) and others metals and metallic
compounds are considered to be highly health hazardous. These find their way through
the water. The environmental application of heterogeneous photo-catalysis includes
removal of heavy metals such as Hg, Cr, Pb, Cd, As, Ni, Cu (Alfano et al., 2000; Hofl et
al., 1997). Removals of these toxic metals are essentially important for human health and
water quality. The photo reducing ability of photo-catalysis has been used to recover
expensive metals from industrial effluent such as gold, platinum and silver (Alfano et al.,
2000).
3. Removing inorganic compounds:
The organic compounds are sensitive to photochemical transformation on the catalyst
surfaces. Inorganic species such as bromated or chlorated azide, halide ions, nitric oxide,
palladium and rhodium species and sulfur species can be decomposed (Balasaraswathy,
2004; Blanco and Malato, 2001). The metal salts such as AgNo3, HgCl and
organometallic compounds (ex.CH3HgCl) as well as cyanide, thio-cyanide, ammonia,
nitrate and nitrites can be removed from water or waste water (Hofl et al., 1997; Wyness
et al., 1994).
4. Water disinfections:
Photo-catalysis can also be used to destroy bacteria and viruses. Streptococcus mutants,
Streptococcus natuss, Streptococcus cricetus, Escherichia coli, Lactobacillus
acidophilus, Scaccharomyces cerevisisas, poliovirus were destructed effectively using
heterogeneous photo catalysis (Priya et al., 2008).
5. Degradation of natural organic matter:
Humic substances (HS) are known to affect the behavior of some pollutants significantly
in naural environments, such as traces of metal speciation and toxicity (Davis et al.,
1994) solubilization and adsorption of hydrophobic pollutant (Blake et al., 1991) and
aqueous photochemistry (Topalov et al., 2000).
Advanced oxidation process has been applied to decrease the organic content in water
including humic acids (Kim et al., 1998; Matthews, 1990; Muneer and Bahnemann, 2001;
Obee, 1996). It has the advantage of not leaving any toxic byproducts, residue or sludge.
The first pioneer work in this field carried out by Bekbolet in 1996 who studied the
effectiveness of photo-catalytic of humic acid (Li et al., 2000).
6. Photo-catalysis and waste water treatment:
The emphasis on treatment technology, including advance oxidation process (AOPs), and
solar irradiation, was placed on their basic principles, applications, and new technological
developments. Merits and demerits of these technologies are compared to highlight their
current limitations and future research needs [Ollis et al., 1991]. The major applications
investigated for this technology are for the removal of colour [March et. al.,1995;
Vinodgopal et al., 1994], reduction of chemical oxygen demand [Mills, 2002; Nogueira
and Jardim, 1996], degradation of harmful fungicides, herbicides, and pesticides
[Klausner et al., 1994;Zou et al., 2005], destruction of hazardous inorganic such as
cyanides [Pare, 2008], treatment of heavy metals [Chiou et al., 2008; Sharma et al.,
2008], mineralization of hazardous organic wastes [Al-Ekabi, 1989; Turchi and Ollis,
1990], purification and disinfection of water [Al-Ekabi and Serpone, 1988], destruction
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Vol 2, No 5, 2011
of malodorous compounds [Canela et al., 1999], decontamination of soil [Hamerski et al.,
1999], decontamination of indoor air [Jacoby, 1995; Obee, 1996] and destruction of
cancer cells [Blake et al., 1999; Okamoto et al., 1985]. The efficiency of TiO2, photo-
fenton and the modified photo-fenton (ferrioxalate) reagent in the presence of solar
irradiation was evaluated for the organic content reduction in terms of dissolved organic
carbon of a municipal or the industrial wastewater [Ahmad and Olli’s, 1984].
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