IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Effect of Inhibitor Concentration and Immersion Time on the Corrosion Rate an...AJSERJournal
The effect of inhibitor concentration and immersion time on the corrosion rate and inhibition efficiency of
AISI 1019 steel in seawater environment were investigated by means of weight loss measurement (WLM) at an interval
of 6days for a period of 60 days. AISI 1019 steel were immersed in seawater solution in the absence and presence of
varying inhibitor concentrations of potassium chromate (PC), Sodium Nitrite(SN), Methyl Orange (MO), Methyl Red
(MR), Terminalia Catappa Leaves (TCL) Extract, Carica papaya Leaves (CPL) Extract. The results showed that there is an
increase in inhibition efficiency with increase in inhibitor concentration and decrease in inhibition efficiency with
increase in immersion time. The inorganic inhibitor (potassium chromate), inorganic inhibitor (Sodium Nitrite), the
organic Inhibitor (Methyl Orange), the organic inhibitor (Methyl Red), the green inhibitor (Terminalia Catappa Leaves)
and green inhibitor (Carica Papaya Leaves) produced their best inhibition efficiency of 71.94%, 634%, 68.94%, 68.32%,
627% ,59.79% respectively at a concentration of 10g/L. From the result obtained, the potassium chromate inhibitor has
better inhibitory property than other inhibitors, which revealed that it is best suited for inhibition of corrosion of mild
steel in seawater environment.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Effect of Inhibitor Concentration and Immersion Time on the Corrosion Rate an...AJSERJournal
The effect of inhibitor concentration and immersion time on the corrosion rate and inhibition efficiency of
AISI 1019 steel in seawater environment were investigated by means of weight loss measurement (WLM) at an interval
of 6days for a period of 60 days. AISI 1019 steel were immersed in seawater solution in the absence and presence of
varying inhibitor concentrations of potassium chromate (PC), Sodium Nitrite(SN), Methyl Orange (MO), Methyl Red
(MR), Terminalia Catappa Leaves (TCL) Extract, Carica papaya Leaves (CPL) Extract. The results showed that there is an
increase in inhibition efficiency with increase in inhibitor concentration and decrease in inhibition efficiency with
increase in immersion time. The inorganic inhibitor (potassium chromate), inorganic inhibitor (Sodium Nitrite), the
organic Inhibitor (Methyl Orange), the organic inhibitor (Methyl Red), the green inhibitor (Terminalia Catappa Leaves)
and green inhibitor (Carica Papaya Leaves) produced their best inhibition efficiency of 71.94%, 634%, 68.94%, 68.32%,
627% ,59.79% respectively at a concentration of 10g/L. From the result obtained, the potassium chromate inhibitor has
better inhibitory property than other inhibitors, which revealed that it is best suited for inhibition of corrosion of mild
steel in seawater environment.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Metals accumulation and As releasing during interaction of clay and iron mine...Agriculture Journal IJOEAR
Abstract— The soil and sediment samples with different content of metals and clay minerals were investigated during bioleaching. The increasing of clay and metal concentrations with decreasing particle size were found both in contaminated soil and sediment. Heterotrophic bioleaching of the iron rich clay fractions from the soil and the sediment were evaluated for his effectiveness in the cycling of iron bound As by consuming organic nutrients. The treatment involved the use of the indigenous bacteria, whose activity was combined with the chelating strength of EDDS, SDS, Na4P2O7 and fertilizers. Heterotrophic bacteria caused decomposition of iron binding deposition as is adsorption on clay with followed dissolving of Fe mainly by the sediment bioleaching. The concentration of iron decreased by precipitation with As sorption after 19 days of sediment bioleaching. The Cu and Zn extraction was inhibited by bioleaching during the iron and arsenic dissolution and precipitation. By contrast, the additives 3mM Cu and 3mM Zn were applied into medium and thus affected the activity of soil resistant heterotrophic bacteria with followed increasing of the iron and arsenic extraction by the soil clay bioleaching. Therefore, this study confirmed the soil and sediment bioleaching in Fe or As releasing efficiency under different conditions regulated by indigenous bacteria. The bioleaching can be a suitable technology for As removal from the untreated soil and sediment by stimulation of the resistant bacteria activity. The separation of clays from the soil and sediment samples did not decreased of toxic element limits because clay and iron minerals coated on coarse silicate particles and the clay fraction is bearers of metals which contaminate the soil and sediment environment.
Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extracted to form a green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Multiple adsorption of heavy metal ions in aqueous solution using activated c...eSAT Journals
Abstract
Batch adsorption of different heavy metal ions (Nickel, Copper, Zinc, Lead, Cadmium and Chromium) in aqueous solution using
activated carbon from Nigerian bamboo was studied. The bamboo was cut, washed and dried. It was carbonized between 3000C -
4500C, and activated at 8000C using nitric acid. The bulk density, iodine number, Benzene adsorption, methylene adsorption, and
ash content of the activated carbon produced compared well with commercial carbons. Multiple adsorption of these metals in
same aqueous solution using bamboo carbon showed that adsorption capacity is in the order Pb>Cd>Cu>Zn>Ni>Cr which
showed that these metal ions can be adsorbed selectively by Nigerian bamboo activated carbon. The order of adsorption is related
to the maximum adsorption of lead, cadmium, copper on bamboo was found to be in the order of ionic radius of the heavy metals
used. Therefore this study demonstrates that bamboo can serve as a good source of activated carbon with multiple metal ions –
removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their
use. However, it will also contribute to the search for less expensive adsorbents and their utilization possibilities for the
elimination of heavy metal ions from industrial waste water.
Key Words: multiple adsorption, heavy metals, Nigerian bamboo, Activated Carbon,
Study of corrosion control effect of H2S scavengers in drilling fluidsMutiu K. Amosa, Ph.D.
Selected environmentally benign iron compounds (synthetic magnetite and ferrous gluconate) have been evaluated as corrosion inhibitors for oil-well steel (N-80) in 50 mg/l sulphide concentration at various pH ranging from 5.5 to 11.5 and at High Temperature, High Pressure (HTHP) conditions by the weight loss method. The test temperatures were 150 °F, 275 °F and 350 °F respectively for pressures of 3 000 psi, 5 000 psi and 6 000 psi. The ferrous complex was found to be a better corrosion inhibitor compared to the synthetic magnetite. It exhibited up to 99.2% inhibition efficiency (IE) when the dose of the scavenger was doubled (i.e. when the sulphide to scavenger ratio was 1:2) irrespective of other factors such as pH, temperature and pressure. Whereas, the synthetic magnetite’s optimum inhibition efficiency (IE) was observed to be up to 75.1% only when the ratio of the sulphide to scavenger was 1:4 at the lowest pH of the experiment (pH 5.5) which is not desirable for a drilling mud. As the pH increases, the inhibition efficiency of the magnetite decreases and found to be lowest at the alkaline pH of 11.5.
Red Dragon Fruit (Selenicereus costaricensis) Waste Peels as Corrosion Inhibi...Innspub Net
Metal corrosion is brought about by the oxidation of atoms on the surface, resulting in irreversible damage to structures at staggering costs. Hence, the search for efficient and cost-effective corrosion inhibitors is relevant. Waste agricultural by-products which have no food or economic value serve as good potential sources for these environmentally benign corrosion inhibitors. Ethanolic extracts of Red Dragon Fruit (RDF) have been previously reported to contain high amounts of flavonoids and polyphenols, which can manifest inhibitory activity against corrosion brought about by aggressive electrolytes. In this study, the ethanolic extract of Selenicereus costaricensis waste peels was tested for its anti-corrosion property using weight loss method. We have also probed its performance as a potential corrosion inhibitor at a range of different temperatures from 303 to 343 K. The calculated inhibition efficiency of 2% RDF was 97%. Thermodynamic studies reveal that increasing inhibitor concentration raises the activation parameters of mild steel in an acidic medium such as activation energy (Ea) and changes in enthalpy (DHo) and entropy (DSo). It was found that the corrosion inhibition process using RDF waste peel extract mainly occurs under diffusion control. Moreover, increased immersion time, inhibitor concentration, and temperature led to increased inhibition efficiency. The spontaneous process (DGoads = -23.47 kJ/mol) of adsorption of RDF on mild steel surfaces obeys the Langmuir isotherm model.
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Ce...CrimsonPublishersACSR
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Cell and a Mobile System by Reyes Astivia MJE, Torres JV*, Barrera GM and Díaz CB in Annals of Chemical Science Research
Biosorption Tool for enviromental cleaning by microorganismsIke Nwiyi
Biosorption is one of the main components of environmental and bioresource technology. Microbes have been widely used in the process of environmental clean-up and are known as bioremediators
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Metals accumulation and As releasing during interaction of clay and iron mine...Agriculture Journal IJOEAR
Abstract— The soil and sediment samples with different content of metals and clay minerals were investigated during bioleaching. The increasing of clay and metal concentrations with decreasing particle size were found both in contaminated soil and sediment. Heterotrophic bioleaching of the iron rich clay fractions from the soil and the sediment were evaluated for his effectiveness in the cycling of iron bound As by consuming organic nutrients. The treatment involved the use of the indigenous bacteria, whose activity was combined with the chelating strength of EDDS, SDS, Na4P2O7 and fertilizers. Heterotrophic bacteria caused decomposition of iron binding deposition as is adsorption on clay with followed dissolving of Fe mainly by the sediment bioleaching. The concentration of iron decreased by precipitation with As sorption after 19 days of sediment bioleaching. The Cu and Zn extraction was inhibited by bioleaching during the iron and arsenic dissolution and precipitation. By contrast, the additives 3mM Cu and 3mM Zn were applied into medium and thus affected the activity of soil resistant heterotrophic bacteria with followed increasing of the iron and arsenic extraction by the soil clay bioleaching. Therefore, this study confirmed the soil and sediment bioleaching in Fe or As releasing efficiency under different conditions regulated by indigenous bacteria. The bioleaching can be a suitable technology for As removal from the untreated soil and sediment by stimulation of the resistant bacteria activity. The separation of clays from the soil and sediment samples did not decreased of toxic element limits because clay and iron minerals coated on coarse silicate particles and the clay fraction is bearers of metals which contaminate the soil and sediment environment.
Ginger extract as corrosion inhibitor from natural resources was studied to prevent corrosion of mild steel in acid media. Ginger rhizome was extracted to produce green corrosion inhibitor (G-1) while ginger powder bought at supermarket was also extracted to form a green corrosion inhibitor (G-2). Effectiveness of inhibitor in preventing corrosion process of mild steel was studied in 1.0 M of hydrochloric acid
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Multiple adsorption of heavy metal ions in aqueous solution using activated c...eSAT Journals
Abstract
Batch adsorption of different heavy metal ions (Nickel, Copper, Zinc, Lead, Cadmium and Chromium) in aqueous solution using
activated carbon from Nigerian bamboo was studied. The bamboo was cut, washed and dried. It was carbonized between 3000C -
4500C, and activated at 8000C using nitric acid. The bulk density, iodine number, Benzene adsorption, methylene adsorption, and
ash content of the activated carbon produced compared well with commercial carbons. Multiple adsorption of these metals in
same aqueous solution using bamboo carbon showed that adsorption capacity is in the order Pb>Cd>Cu>Zn>Ni>Cr which
showed that these metal ions can be adsorbed selectively by Nigerian bamboo activated carbon. The order of adsorption is related
to the maximum adsorption of lead, cadmium, copper on bamboo was found to be in the order of ionic radius of the heavy metals
used. Therefore this study demonstrates that bamboo can serve as a good source of activated carbon with multiple metal ions –
removing potentials and may serve as a better replacement for commercial activated carbons in applications that warrant their
use. However, it will also contribute to the search for less expensive adsorbents and their utilization possibilities for the
elimination of heavy metal ions from industrial waste water.
Key Words: multiple adsorption, heavy metals, Nigerian bamboo, Activated Carbon,
Study of corrosion control effect of H2S scavengers in drilling fluidsMutiu K. Amosa, Ph.D.
Selected environmentally benign iron compounds (synthetic magnetite and ferrous gluconate) have been evaluated as corrosion inhibitors for oil-well steel (N-80) in 50 mg/l sulphide concentration at various pH ranging from 5.5 to 11.5 and at High Temperature, High Pressure (HTHP) conditions by the weight loss method. The test temperatures were 150 °F, 275 °F and 350 °F respectively for pressures of 3 000 psi, 5 000 psi and 6 000 psi. The ferrous complex was found to be a better corrosion inhibitor compared to the synthetic magnetite. It exhibited up to 99.2% inhibition efficiency (IE) when the dose of the scavenger was doubled (i.e. when the sulphide to scavenger ratio was 1:2) irrespective of other factors such as pH, temperature and pressure. Whereas, the synthetic magnetite’s optimum inhibition efficiency (IE) was observed to be up to 75.1% only when the ratio of the sulphide to scavenger was 1:4 at the lowest pH of the experiment (pH 5.5) which is not desirable for a drilling mud. As the pH increases, the inhibition efficiency of the magnetite decreases and found to be lowest at the alkaline pH of 11.5.
Red Dragon Fruit (Selenicereus costaricensis) Waste Peels as Corrosion Inhibi...Innspub Net
Metal corrosion is brought about by the oxidation of atoms on the surface, resulting in irreversible damage to structures at staggering costs. Hence, the search for efficient and cost-effective corrosion inhibitors is relevant. Waste agricultural by-products which have no food or economic value serve as good potential sources for these environmentally benign corrosion inhibitors. Ethanolic extracts of Red Dragon Fruit (RDF) have been previously reported to contain high amounts of flavonoids and polyphenols, which can manifest inhibitory activity against corrosion brought about by aggressive electrolytes. In this study, the ethanolic extract of Selenicereus costaricensis waste peels was tested for its anti-corrosion property using weight loss method. We have also probed its performance as a potential corrosion inhibitor at a range of different temperatures from 303 to 343 K. The calculated inhibition efficiency of 2% RDF was 97%. Thermodynamic studies reveal that increasing inhibitor concentration raises the activation parameters of mild steel in an acidic medium such as activation energy (Ea) and changes in enthalpy (DHo) and entropy (DSo). It was found that the corrosion inhibition process using RDF waste peel extract mainly occurs under diffusion control. Moreover, increased immersion time, inhibitor concentration, and temperature led to increased inhibition efficiency. The spontaneous process (DGoads = -23.47 kJ/mol) of adsorption of RDF on mild steel surfaces obeys the Langmuir isotherm model.
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Ce...CrimsonPublishersACSR
Properties of Zinc Phosphate Coatings on Carbon Steel Using a Thermostatic Cell and a Mobile System by Reyes Astivia MJE, Torres JV*, Barrera GM and Díaz CB in Annals of Chemical Science Research
Biosorption Tool for enviromental cleaning by microorganismsIke Nwiyi
Biosorption is one of the main components of environmental and bioresource technology. Microbes have been widely used in the process of environmental clean-up and are known as bioremediators
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Synthesis of Calcium Silicate (Casio3) Using Calcium Fluoride, Quartz and Mic...IJERA Editor
Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature,
ores or minerals of different compounds are formed due to microbial environment and other factors like
weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals.
Chemical reactions occur under microbial environment because microbes have the ability to control or modify
different factors like pH, chemical potential and temperature during reactions. In this paper, synthesis of calcium
silicate (CaSiO3) using calcium fluoride (CaF2) and quartz (SiO2) under microbial environment in a laboratory is
being adopted to produce the required material. XRD technique is used to confirm the formation of CaSiO3.
Removal of lead (II) and copper (II) ions from aqueous solution by baobab (Ad...IOSR Journals
High concentration of heavy metals in the environment can be detrimental to a variety of living species. The purpose of this research was to explore the use of baobab (Adsononsia digitata) fruit shells in the removal of lead(II) and copper(II) ions from aqueous solutions. Batch experiments were conducted to determine the effect of varying adsorption parameters on the removal of aqueous lead and copper ions. The adsorption of Pb(II) was found to be maximum at pH 5.5 using adsorbent dose of 0.7 g. The adsorption of Cu(II) was found to be optimum at pH 6 using adsorbent dosage of 0.9 g. The adsorption data conformed to Langmuir, Freundlich and Temkin isotherms. However the Temkin isotherm showed the best fitting model with highest R2 values for both lead and copper (0.9977 and 0.9967) respectively. Baobab fruit shells can be used as a cost effective adsorbent for the removal of lead(II) and copper(II) ions from aqueous solutions in the treatment of industrial effluent.
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.
Removal of Cu(II) Ions from Aqueous Solutions by Adsorption Onto Activated Ca...IJERA Editor
This paper studied the ability of using local activated carbon (LAC) derived from olive waste cakes as an
adsorbent for the removal of Cu(II) ions from aqueous solution by batch operation. Various operating parameters
such as solution pH, adsorbent dosage, initial metal ions concentration, and equilibrium contact time have been
studied. The results indicated that the adsorption of Cu(II) increased with the increasing pH, and the optimum
solution pH for the adsorption of Cu(II) was found to be 5. The adsorption process increases with increasing
dosage of LAC, also the amount of Cu(II) removed changes with Cu(II) initial concentration and contact time.
Adsorption was rapid and occurred within 25 min. for Cu(II) concentration range from 60 to 120 mg/l
isothermally at 30±1 oC. Maximum adsorption occurs at Cu(II) initial concentration lesser than 100 mg/l by
using adsorbent dosage (1.2 g/l). The equilibrium adsorption data for Cu(II) were fitted well with the Langmuir
and Freundlich adsorption isotherm models. The maximum adsorption capacity of LAC was found to be 106.383
mg/g. So, the results indicated the suitability use of the activated carbon derived from olive waste cakes (LAC)
as low cost and natural material for reliable removal of Cu(II) from water and wastewater effluents.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Equilibrium and Kinetics Adsorption of Cadmium and Lead Ions from Aqueous Sol...theijes
Sourcing cheap adsorbents for the treatment of waste water is imperative for local environments. The adsorption of cadmium (Cd) and lead (Pb) from aqueous solution onto bamboo activated carbon prepared by chemical activation with ZnCl2 was investigated. The unwashed chemical activated bamboo carbon (UCABC) achieved up to 87.81% and 96.45% removal of Cd and Pb at pH-5 and 11, respectively. Removal equilibrium was attained within 1hr and 2.5hrs for Cd and Pb, respectively. The Cd and Pb adsorption increased with adsorbent dosage decrease while removal rate (%) increased with Cd and Pb concentration. Adsorption isotherm of Cd and Pb onto UCABC was determined and correlated with four isotherm models (Langmuir, Freundlich, Temkin and Hills). The equilibrium data fitted into Freundlich Cd (R2 = 0.9873, SSE = 0.045), Pb (R2 =0.9903, SSE = 0.051); Temkin Cd (R2 =0.9730, SSE = 0.052), Pb (R2 = 0.9079, SSE = 0.056); Hills Cd (R2 = 0.9961, SSE = 0.048), Pb (R2.= 0.9183, SSE = 0.053) and Langmuir Cd (R2 = 0.9653, SSE = 0.302), Pb (R2 = 0.9899, SSE = 0.136) isotherms. The Freundlich fitting showed isotherm adsorption capacity constants Kf = 7.843 and 5.098 (mg/g) for Cd and Pb, respectively. Furthermore, their adsorption kinetics correlated with the Pseudo-first order, Pseudo-second order and Intra-particle diffusion models and could be best described by the Pseudo-second order equation, suggesting chemisorptions as the limiting process. This study demonstrated that the UCABC can remove Cd2+ and Pb+ ions from aqueous solution to avert expensive commercial adsorbents
The corrosion inhibition of carbon steel in seawater solution (3.5%NaCl and DMSO) by pure
curcumin has been studied at temperature range (298-328K) and different concentrations (2.7*10-6
,1.3*10-5
,2.7*10-
5
,3.2*10-5M) using potentiostatic techniques. The results showed that the best corrosion inhibition efficiency was
obtained with2.7*10-5Mpure curcumin concentration which reach to 77.5% at 298K.The corrosionrate increase
with increase temperature at all purecurcuminconcentrations.Thecorrosion rate decreasewith
purecurcuminconcentration increaseup to 2.7*10-5Mthen with increasing pure curcumin concentration than 2.7*10-
5M the corrosion ratewill be increase. Apparent activation energy, Arrhenius factor, free energyΔG*
, enthalpy ΔH*
and entropy ΔS*
for corrosion processeswere calculated. The inhibition mechanism according to adsorption of pure
curcumin molecules in the interface metal/solution and Langmuir adsorption isotherm type were applied.
The International Journal of Engineering and Science (The IJES)theijes
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.
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
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Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
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What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
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Execution from the test manager
Orchestrator execution result
Defect reporting
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Cx32617623
1. Mataqi, K.Y. , Akbar, B.H. / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
Sulfur cycle of microbial corrosion on carbon steel in soil model
Mataqi, K.Y. *, Akbar, B.H.**
*(Department of Biotechnology, Kuwait Institute for Scientific Research, Kuwait)
** (Department of Biotechnology Kuwait Institute for Scientific Research, Kuwait)
ABSTRACT which either oxidize or reduce sulphur compounds as
This study examined the effects of some part of their life process. Although many
Desulfovibrio desulfricans and bacteria consortia culturable bacterial types with known corrosion
on the rate of carbon steel corrosion in soil model. effects have been identified [5], in both aquatic and
Microbial corrosion was measured using the terrestrial environments the primary corrosion-
corroded mean depth after 56 days incubation causing bacteria are the sulfate-reducing iron-
under aerobic and anaerobic conditions. The oxidizing bacteria. Desulfovibrio desulfricans is
effects of water content and dissolved oxygen in examined in this report as a source of Sulfate
soil on the corrosion rate were also analyzed. reducers, which is found to exist in all soil and water
Results showed that aerobic conditions increased types, as well as lives symbiotically with facultative
corrosion rate. Moreover, sole Desulfovibrio anaerobic bacteria [6]. Sulfate-reducing bacteria
desulfricans treatment ceased the corrosion as a (SRB) are a group of anaerobic diverse organisms in
protective ferrous sulfide film formed on the which have varied morphological and nutritional
carbon steel. While the heterogeneous biofilm of characteristics. They utilize organic matter to produce
the bacterial consortia formed uneven oxygen sulfide by either reducing or oxidizing sulfate
concentration which accelerated the corrosion. compounds [7] , as a source of energy. Therefore,
sulphate (SO42–) can be reduced to sulphide (S2–) by
Keywords - Bacteria , Carbon steel, Corrosion, SRB leading to the generation of hydrogen sulfide as
SRB, Desulfovibrio desulfricans a metabolic bi-product. Both physical and chemical
processes transfer Hydrogen sulfide (H2S) across the
I. Introduction air and water boundaries to environments where
Corrosion is an ever-present degradation mechanism chemoautotrophic bacteria oxidize the sulfide to
in wetted components and systems. There are many sulfuric acid [8]. The corrosion process will hence
forms of corrosion in metals, that include; pitting, occur by the reaction of the biogenic sulfuric acid
stress corrosion, general corrosion, galvanic with the metallic surfaces [9]. In order to evaluate the
corrosion, and others [1], in which microbiologist significance of microbial corrosions, a look at the
have recognized and are constantly addressing. economical perspective on such effects is essential.
When a system ` first encounters microbial corrosion In 2001, the cost of microbial-influenced corrosion
(MC) such event usually occurs during the system on oil and gas industries accounted for about $2
initial exposure to an aqueous environment, such as billion annually [10]. Microbial induced corrosion in
during hydrotest, wet lay-up, or moist soil. The the US economy has reached $350 billion annually as
presence of certain bacteria in an environment will of 2010 [11]. Mild steel in used widely in piping
lead to the production of microbial corrosions. This systems, storage tanks, cooling towers and aquatic
mode of corrosion can be accelerated by microbial structures and is the most readily corroded metals
organisms, either because they manufacture [12]. Since bacteria form colonies beneath which
aggressive species, such as protons or sulphide ions, corrosion can occur, prevention of colonization is one
or because they catalyze the electrochemical of the potential ways to prevent MC. This report will
reactions themselves [2]. MC induction also requires examine the effects of Desulfovibrio desulfricans and
the presence of nutrients and water to ensure the bacteria consortia on the rate of carbon steel
survival and growth of microorganisms. Thus, the corrosion in soil model with respect to dissolved
ability of microorganisms to sense and rapidly oxygen and water content distribution in such a
response to harsh environmental changes is vital for system.
their survival and MC capabilities [3]. Microbes can
grow in fluids with pH values ranging from -1 to 10, II. Materials and Methods
where -1 is the most acidic concentration, and derive 2.1 Organisms
energy from organic or inorganic materials. The sulfate reducing bacterial stain
Moreover, microbes can survive temperatures which Desulfovibrio desulfricans DSMZ 642 was used as
range from -4 to 210oF (-20 to 99oC) [4]. The the model SRB in this study. Activated sludge from a
majority of the active organisms involved in municipal wastewater plant was used as model
corrosion are bacteria, about 1-5 micrometers long, Bacteria consortia.
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(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
2.2 Culture medium 30mL vial bottle; (2) butyl rubber plug; (3) aluminum
Modified Baar`s Medium (MBM), containing (in cap; (4) Na2S solution in 500µL microtube; (5)
g/L) anhydrous sodium citrate 5.0, 50% sodium carbon steel coupons; (6) culture medium in SiO2
lactate 4.9, yeast extract 1.0, NH4Cl 1.0, soil. (B) Aerobic conditions: (7) 50mL centrifuge
MgSO4.7H2O 2.0, CaSO4 1.0, and K2HPO4 0.5, was tube; (8) silicone plug.
used as culture medium. The pH, sulfate To create artificial model soil, 30mL vials (Nichiden
concentration and total organic carbon concentration Rika Garasu, Hyogo) containing 25g silicon dioxide
(TOC) of MBM are 7.0, 1500 mg/L, and 2500 mg/L, (SiO2) sand, a 500µL microtube, and three carbon
respectively. SRB and activated sludge were pre- steel coupons were autoclaved, sealed with a butyl
incubated in MBM at 37oC and 25oC, respectively, rubber plug and an aluminum cap, and replaced with
for seven days. Then, one-tenth of these pre- N2 gas (N2 >99.9995%) (Figure, 1A). To maintain
incubated culture broths were inoculated into test the anaerobic conditions throughout the experiment,
culture medium. The inoculated SRB size was 4x105 400µL of 27.2g/L Na2S solution was poured into the
colony forming unit (CFU) CFU/mL D. desulfricans microtube. Then, 7.5mL of the degassed culture
and 3x107 CFU/mL facultative anaerobic bacteria. medium was inoculated. To maintain aerobic
The inoculated activated sludge size was 7500mg/L conditions, a 50mL centrifuge tube containing 25g
mixed liquor suspended solid (MLSS). Sterile MBM SiO2 and three carbon steel coupons was autoclaved.
was prepared by autoclaving the medium at 120̊ C for Followed by the inoculation with 7.5mL of the
20min. culture medium (Fig, 1B).
2.3 Carbon steel coupons preparation 2.6 Measurement of water content on corrosion
Rectangular carbon steel coupons (20x10mm and To investigate the effects of water content on
0.35mm thick) were cut from a sheet stock. The corrosion, 4.5 or 1.5mL culture medium was
composition of the carbon steel coupons was (in wt inoculated. Water content (WC) was defined as the
%) 99.71 Fe, 0.03 C, 0.01 Si, 0.19 Mn, 0.013 P, ratio of water volume to void of the model soil.
0.017 S, 0.0017 N, and 0.026Al. The surface was Since the void of 25g SiO2 7.5mL, addition of 7.5,
wet-polished with 800-grid polishing paper. The 4.5 and 1.5mL of culture medium resulted in 100, 60
polished coupons were cleaned ultrasonically in and 20% WC, respectively. To keep the water
acetone for 15min, weighed, air-dried, and stored in a constant in the test tube, sterile water was added and
desecrator. the tube was centrifuged (1500G, 3min) every week.
2.4 Corrosion Measurements After incubation for 0, 7, 14, 28, and 56 d, saline
The corroded mean depth (CMD) was used as an (NaCl 8.0 g/L, KCl 0.2 g/L) was added to the model
indicator of the extent of corrosion. Corrosion soil. The model soil was sonicated for 20 sec, and
products were selectively removed from tested mixed with a spatula.
coupons by incubating at 60oC for 60 min in a 10wt% 2.7 Measurement of Total Organic Carbon and
HCl solution with 0.3vol% Ibit, a polycationic amine Sulfate Concentrations
derivative that protects metal steel surface from HCl. Sulfate concentration and TOC concentration in the
Then the treated coupons were weighed. Mass loss culture was measured by sulfur analyzer Antek (9000
of the carbon steel coupon was divided by the Series) and a TOC analyzer, respectively. The pH of
specific gravity of iron (7.86g/cm3) and by the area the culture tenfold-diluted solution was measured by
(cm2) of the carbon steel coupon, and CMD was a pH meter. Corrosion products were selectively
derived. removed from the corroded carbon steel coupons as
2.5 Model soil preparation described above. The roughness of the coupon was
analyzed by a laser 3D profile microscope (VK-
8500).
2.8 Bacterial count
To count the aerobes in the culture, saline was added
to the model soil and the supernatant was spread-
plated on Minimized Luria-Bertani (MLB) agar plate,
containing (in g/L) polypeptone 1.0, yeast extract 0.5,
NaCl 10.0, and agar 15, in triplicate. After
incubation for 7 d at 28oC, the observed colonies
were counted as aerobes. For the counting of
anaerobes and SRB in the experimental culture, the
supernatant was added dropwise to the plates and the
MBM agar medium with 173 (in g/L)
Fe(NH4)2(SO4)2 was poured. The plates were
incubated in sealed jars with an oxygen absorbing
Figure 1. Experimental apparatuses for preparation of and carbon dioxide generating agent. After
artificial model soil. (A) Anaerobic conditions: (1) incubation for 14 d at 37oC, the observed black
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3. Mataqi, K.Y. , Akbar, B.H. / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
colonies were counted as SRB and others were Figure 2. Time Course of CMD (A), sulfate
counted as anaerobes. The concentration of bacteria concentration (B), TOC concentration (C) , and pH
was expressed as (CFU) per mL. (D) under anaerobic ( , , , ) and aerobic ( , ,
) conditions. The test was conducted in SRB culture
III. Results ( , ), bacterial consortia ( , ) and in sterile
3.1 Analysis of corroded carbon steel conditions as a control ( , ).
The CMDs of carbon steel coupons under
anaerobic and aerobic conditions were compared
after 56 days incubation period. In Bacterial Table 1. Effect of dissolved Oxygen Existence and
consortia, the CMD under aerobic conditions reached Bacteria on Endpoint CMD (µm) after 56 days
34.1 µm, which was 28 times higher than anaerobic Incubation
conditions with CMD measurement of only 1.2 µm. SRB Bacterial Sterile
However, the CMD for SRB-inoculation or sterile consortia
conditions reached 5.42 or 5.11 µm respectively, in
which was 8.9 or 8.8 times higher than the anaerobic
conditions (Fig. 2A, Table 1). There weren’t any Anaerobic 0.61 1.2 0.58
significant differences between SRB and sterile
control conditions, yet in Bacterial consortia a
change was noted with 2.1 and 6.7 times increase in Aerobic 5.42 34.1 5.11
anaerobic and aerobic treatments respectively, when
compared with sterile CMD values. These
observations indicated that existence of oxygen Upon inoculation of SRB under aerobic conditions,
causes carbon steel corrosion in model soil. little corrosion on the steel coupons was observed
during the 14-28 days incubation period. In the
model soil analyzed, a gap separating the soil into
upper and lower parts was observed just after
incubation for 7 days. This gap seemed to influence
corrosion acceleration, as the coupons were corroded
unexpectedly at day 7. The whole surface of coupon
immersed into the SRB culture was covered with
homogeneous black corrosion products that were
easily wiped off. When the corroded coupons were
incubated with HCl, hydrogen sulfide (H2S) gas was
produced, indicating that FeS was formed. In
addition, local corrosion under black tubercles was
observed under aerobic conditions. These
observations showed that the sole existence of SRB
didn`t accelerate carbon steel corrosion, while that of
Bacterial consortia did indeed accelerate the
corrosion process.
3.2 Influence of pH, Sulfate and TOC concentrations
on bacterial growth over time
Sulfate concentration for the SRB inoculated in both
anaerobic and aerobic conditions stopped decreasing
at day 7 suggesting that the sulfate-reducing activity
of SRB was high until this day as it began to decrease
afterwards. While, the sulfate concentration for
Bacterial consortia stopped decreasing at day 14
(Fig. 2B). Incubation of carbon steel coupons with
SRB or Bacterial consortia inoculae lead to the
depletion of TOC concentration at day 7;
furthermore, heterotrophic bacteria were inactive
during the 14-56 day incubation period (Fig. 2C) and
the concentration of aerobes decreased as well (Fig.
3A). Under anaerobic conditions, the TOC was not
consumed completely, because oxygen as electron
acceptor was limited. TOC concentration decreased
even under sterile conditions. In another experiment
with sterile conditions that did not contain carbon
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4. Mataqi, K.Y. , Akbar, B.H. / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
steel coupons, the TOC concentration however did
not decrease (data not shown). This indicates that the
corrosion products adsorbed the organic carbon.
Under anaerobic conditions, SRB concentration was
decreased and became negligible during the 28-56
day incubation period (Fig. 3C). This is due to the
fact that insufficient sulfate and hydrogen sulfide that
filled the tested bottle inhibited the growth of SRB.
Under aerobic conditions, the presence of SRB
suggested the formation of anaerobic regions in the
soil.
When examining the pH concentration under
anaerobic conditions, it increased to 7.9 after
incubation for 7 days and remained constant for 50
days. On the other hand, the pH under aerobic
conditions was slightly higher as it increased to 9
after similar incubation time and remained constant
for 50 days as well (Fig. 2D). In SRB culture
incubated under both anaerobic and aerobic
conditions, there was no detection of SRB during the
28-56 day incubation period (Fig. 3C). In contrast,
Bacterial consortia cell concentrations reached 108
CFU/mL under aerobic conditions, while SRB
reached just over 105 CFU/mL, after incubation for
28 days. As for the sulfate concentration, it remained
around 1400mg/L throughout the experiment. The
increase of SRB at 7 day incubation time indicated
that SRB was not dormant and sulfate-reducing
activity occurred during this time. This observation
suggested that sulfur-oxidizing bacteria (SOB)
generated sulfate and lived symbiotically with SRB,
in addition to the oxidation of sulfide within the
dissolved oxygen.
Figure 3. Time course on the concentration of
aerobes (A), anearobes (B), and SRB (C). Incubation
was carried out under anaerobic ( , ) and aerobic
( , ) conditions. , :In SRB culture, ,
: In bacterial consortia. Cell concentrations were
meausred over a 60 day (d) period.
3.3 Characteristic of SRB colonies
For the counting of SRB in the culture of Bacterial
consortia, the culture broth was inoculated into
MBM agar plate under anaerobic condition. After
incubation for 7 days, a black colony was observed in
the plate. Following this period, the entire plate
became black due to H2S produced from the SRB
colony. Clear zones surrounding the bacterial
colonies in the FeS on the MBM agar plates were
observed (Fig. 4).
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5. Mataqi, K.Y. , Akbar, B.H. / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
Figure 4. Clear zones surrounding the bacterial
colonies in the FeS on the MBM agar plates
incubated under anaerobic conditions.
3.4 Effects of Water Content on carbon steel coupons
roughness
In case of 60% WC, the boundary line
between water phase and air phase was observed at
the center of the carbon steel coupons. Yet, for 20%
WC, the boundary line was not observed on the
coupons. Examination of the eroded region on the
corroded coupon in terms of 60% WC, it was limited
to the lower half (Fig. 5C). On the other hand, in the
case of 20% WC, the eroded region was observed
over the whole area on the coupons. Shiny metal
surfaces remained after incubation for 56 days (Fig.
5D). In comparison with 100% WC, the eroded
region was observed over the entire coupon, and
developed pitting was observed (Fig. 5B). The CMD Figure 5. Surface roughness analysis of corroded
under sterile conditions with 60% WC reached carbon steel coupons immersed in bacterial consortia
22.5µm and was 4.4 times higher than 100% WC under 100, 60 and 20% WC conditions. Corrosion
(5.11µm) after incubation for 56 days (Fig. 6B, Table products were selectively removed and the roughness
2). CMD was directly proportional to the incubation of the metal surface was analyzed. The control
time (R2= 0.993). CMD under sterile conditions with coupon was immersed in sterile conditions. Under
20% WC reached 30.0µm and was 5.9 times more 60% WC condition, the lower half of coupon was
than 100% WC after incubation for 56 days. The eluted. Under 20% WC condition, shiny metal
CMD was directly proportional to the incubation time surfaces were observed.
(R2 = 0.999).
Figure 6. Time course of CMD in bacterial consortia
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(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
( , , ) and sterile conditions ( , , ) with carried out under 100% WC ( ), 60% WC ( ), and
100% WC ( , ), 60% WC ( , ), and 20% 20% WC ( ). Cell concentrations were meausred
WC ( , ). over a 60 day (d) period.
Cell concentrations were meausred over a 60 day (d)
period. IV. Discussion
Aerobic conditions accelerated the corrosion
of carbon steel in model soil. SRB inoculation
Table 2. Effect of Water Content on Endpoint CMD inhibited the corrosion under aerobic conditions at
(µm) after 56 days Incubation day 14 and 28. The whole surfaces of the corroded
Bacterial Sterile steel coupons were covered with homogeneous
consortia sulfide (FeS). Ma et al. reported that corrosion of
99.99% pure iron immersed in solution was inhibited
100% WC 34.1 5.11 by a protective layer of FeS under such conditions as
less than 0.04 mmol dm-3 H2S concentration, a pH
60% WC 35.9 22.5 value of 3-5 and an immersion time longer than 2 h
[13]. When the entire coupon surface was covered
20% WC 37.1 30.0 with homogeneous ferrous sulfide, corrosion of
carbon steel was inhibited. Under anaerobic or
aerobic condition, sulfate concentration for the SRB
Bacterial consortia accelerated the corrosion of the
inoculated condition stopped decreasing at day 7
carbon steel coupons under three WC conditions. because of either the product (H2S) inhibition or
CMDs in the cases of 100, 60 and 20% WC reached
lactate depletion, respectively. The observation
34.1, 35.9 and 37.1µm, respectively after incubation
under anaerobic condition indicated that hydrogen
for 56 days (Fig. 6A, Table 2). In the case of 100%
sulfide didn`t accelerate corrosion of carbon steel.
WC, CMD was slightly increased until the 14th
Corrosion acceleration by SRB activity such as the
incubation day and the corrosion rate was accelerated cathodic depolarization was stopped at day 7.
after that. No distinct difference in CMD among the
Bacterial consortia accelerated the corrosion of
three WC conditions was observed nor was there any
carbon steel. However, in the soil contained water,
detection of SRB after incubation for 56 days. The little convection occurred. Therefore, segregation of
concentrations of aerobes and anaerobes decreased bacterial habitat and uneven distribution of dissolved
under incubation with all three WC conditions (Fig. oxygen in the culture were considered to be formed
7).
in the soil. It is indicated that the heterogeneous
structure led to the formation of a heterogeneous
biofilm with corrosion products on the carbon steel
coupons. The heterogeneous biofilm that resulted in
the uneven distribution of dissolved oxygen on the
metal surface and the formation of oxygen
concentration cells accelerated microbial corrosion.
Therefore, the heterogeneity caused acceleration in
model soil. Dubiel et al. reported that the corrosion
of carbon steel in the culture inoculated with both
SOB and SRB was accelerated compared to that in
the culture inoculated with either SOB or SRB [14].
In our experiments, SRB colonies and FeS were
observed on MBM agar plates inoculated with
Bacterial consortia culture. The entire plate became
black due to H2S produced by the SRB colony. Clear
zones surrounding the bacterial colonies in the FeS
were observed. On the carbon steel coupons
immersed into Bacterial consortia, the protective FeS
film formed by SRB was broken by the bacteria
observed in the clear zone. The bacteria were
considered to be SOB and the mechanism of
corrosion was proposed in Fig. 8. That is being, (1)
SRB generate H2S from sulfate, (2) carbon steel
coupons are protected by FeS, (3) SOB break the
protective FeS film and sulfate is generated.
Figure 7. Time course of concentration of aerobes
(A), anaerobes (B), and SRB (C). Incubation was
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(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 2, March -April 2013, pp.617-623
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