The Experts below are selected from a list of 23712 Experts worldwide ranked by ideXlab platform

Gaydardzhiev Stoya - One of the best experts on this subject based on the ideXlab platform.

  • Bioleaching of Metals from Pyrolised Printed Circuit Boards using Coal as External Sulphur Source
    2019
    Co-Authors: Arinanda Muhammad, Van Haute Quenti, Lambe Fanny, Gaydardzhiev Stoya
    Abstract:

    Copper-rich char from pyrolysis of obsolete printed circuit boards (PCBs) was processed using bio- and hydrometallurgical means. Preliminary results demonstrated the potential of copper leaching using an acidic, ferric iron lixiviant derived from coal waste containing pyrite and subjected to accelerated bioleaching. The presented results report on the role bacterial presence plays in the leaching System, the main challenge being to outline the optimal con-ditions under which bacteria survive in the harsh leaching environment. The results are highlighting the importance of finding an appropriate sulphur source to be added in the char leaching System in order to keep the moderate thermophile microbial consortia viable. Tail-ings fraction derived from gravity beneficiation of coal was chosen as such due to its sulphur content and in view of its reutilization potential. The influence of the coal addition degree (%wt ratio) to the char, on the dissolution of the zero valent metals (copper, aluminum) and bacterial activity was studied. Other process relevant parameters such as pH, redox potential and ferric-ferrous iron balance were followed as well. It was found out, that an addition of coal fraction, do stimulate bacterial activity inside the reactor which results in higher degree of copper dissolution (97%) after 168 hours, in comparison to the aBiotic System (89%) and Biotic System where coal is absent (93%) over the same time span. Although a very fine granulometric fraction of the coal was explicitly used, there was virtually no indication of metal back-sorption onto coal particles. The fact that copper was brought into solution by ferric iron at starting concentrations well below the stoichiometric requirement, implies bacterial regeneration of the ferric iron and its cycling in the System

  • Bioleaching of Metals from Pyrolised Printed Circuit Boards using Coal as External Sulphur Source
    2019
    Co-Authors: Arinanda Muhammad, Van Haute Quenti, Lambe Fanny, Gaydardzhiev Stoya
    Abstract:

    audience: researcher, professional, studentCopper-rich char from pyrolysis of obsolete printed circuit boards (PCBs) was processed using bio- and hydrometallurgical means. Preliminary results demonstrated the potential of copper leaching using an acidic, ferric iron lixiviant derived from coal waste containing pyrite and subjected to accelerated bioleaching. The presented results report on the role bacterial presence plays in the leaching System, the main challenge being to outline the optimal con-ditions under which bacteria survive in the harsh leaching environment. The results are highlighting the importance of finding an appropriate sulphur source to be added in the char leaching System in order to keep the moderate thermophile microbial consortia viable. Tail-ings fraction derived from gravity beneficiation of coal was chosen as such due to its sulphur content and in view of its reutilization potential. The influence of the coal addition degree (%wt ratio) to the char, on the dissolution of the zero valent metals (copper, aluminum) and bacterial activity was studied. Other process relevant parameters such as pH, redox potential and ferric-ferrous iron balance were followed as well. It was found out, that an addition of coal fraction, do stimulate bacterial activity inside the reactor which results in higher degree of copper dissolution (97%) after 168 hours, in comparison to the aBiotic System (89%) and Biotic System where coal is absent (93%) over the same time span. Although a very fine granulometric fraction of the coal was explicitly used, there was virtually no indication of metal back-sorption onto coal particles. The fact that copper was brought into solution by ferric iron at starting concentrations well below the stoichiometric requirement, implies bacterial regeneration of the ferric iron and its cycling in the System.CERe

Arinanda Muhammad - One of the best experts on this subject based on the ideXlab platform.

  • Bioleaching of Metals from Pyrolised Printed Circuit Boards using Coal as External Sulphur Source
    2019
    Co-Authors: Arinanda Muhammad, Van Haute Quenti, Lambe Fanny, Gaydardzhiev Stoya
    Abstract:

    Copper-rich char from pyrolysis of obsolete printed circuit boards (PCBs) was processed using bio- and hydrometallurgical means. Preliminary results demonstrated the potential of copper leaching using an acidic, ferric iron lixiviant derived from coal waste containing pyrite and subjected to accelerated bioleaching. The presented results report on the role bacterial presence plays in the leaching System, the main challenge being to outline the optimal con-ditions under which bacteria survive in the harsh leaching environment. The results are highlighting the importance of finding an appropriate sulphur source to be added in the char leaching System in order to keep the moderate thermophile microbial consortia viable. Tail-ings fraction derived from gravity beneficiation of coal was chosen as such due to its sulphur content and in view of its reutilization potential. The influence of the coal addition degree (%wt ratio) to the char, on the dissolution of the zero valent metals (copper, aluminum) and bacterial activity was studied. Other process relevant parameters such as pH, redox potential and ferric-ferrous iron balance were followed as well. It was found out, that an addition of coal fraction, do stimulate bacterial activity inside the reactor which results in higher degree of copper dissolution (97%) after 168 hours, in comparison to the aBiotic System (89%) and Biotic System where coal is absent (93%) over the same time span. Although a very fine granulometric fraction of the coal was explicitly used, there was virtually no indication of metal back-sorption onto coal particles. The fact that copper was brought into solution by ferric iron at starting concentrations well below the stoichiometric requirement, implies bacterial regeneration of the ferric iron and its cycling in the System

  • Bioleaching of Metals from Pyrolised Printed Circuit Boards using Coal as External Sulphur Source
    2019
    Co-Authors: Arinanda Muhammad, Van Haute Quenti, Lambe Fanny, Gaydardzhiev Stoya
    Abstract:

    audience: researcher, professional, studentCopper-rich char from pyrolysis of obsolete printed circuit boards (PCBs) was processed using bio- and hydrometallurgical means. Preliminary results demonstrated the potential of copper leaching using an acidic, ferric iron lixiviant derived from coal waste containing pyrite and subjected to accelerated bioleaching. The presented results report on the role bacterial presence plays in the leaching System, the main challenge being to outline the optimal con-ditions under which bacteria survive in the harsh leaching environment. The results are highlighting the importance of finding an appropriate sulphur source to be added in the char leaching System in order to keep the moderate thermophile microbial consortia viable. Tail-ings fraction derived from gravity beneficiation of coal was chosen as such due to its sulphur content and in view of its reutilization potential. The influence of the coal addition degree (%wt ratio) to the char, on the dissolution of the zero valent metals (copper, aluminum) and bacterial activity was studied. Other process relevant parameters such as pH, redox potential and ferric-ferrous iron balance were followed as well. It was found out, that an addition of coal fraction, do stimulate bacterial activity inside the reactor which results in higher degree of copper dissolution (97%) after 168 hours, in comparison to the aBiotic System (89%) and Biotic System where coal is absent (93%) over the same time span. Although a very fine granulometric fraction of the coal was explicitly used, there was virtually no indication of metal back-sorption onto coal particles. The fact that copper was brought into solution by ferric iron at starting concentrations well below the stoichiometric requirement, implies bacterial regeneration of the ferric iron and its cycling in the System.CERe

Aruliah Rajasekar - One of the best experts on this subject based on the ideXlab platform.

  • Myco-Synthesis of Zinc Oxide Nanoparticles as Potent Anti-corrosion of Copper in Cooling Towers
    Journal of Cluster Science, 2019
    Co-Authors: Parameswaran Sujatha Preethi, Arumugam Arul Prakash, Subramani Abilaji, Chandar Prakash, Ayyakkannu Usha Raja Nanthini, Jayaraman Narenkumar, Aruliah Rajasekar, Gurusamy Valli
    Abstract:

    This study demonstrated that, myco-synthesis of zinc oxide nanoparticles (ZnONPs) using the aqueous extract of button mushroom ( Agarius bisporus ) as a reducing agent. The nanoparticle formation was evaluated by UV–visible spectroscopy, Fourier Transform-Infrared spectroscopy, X-ray Diffraction spectroscopy, Energy Dispersive X-ray spectroscopy, and Transmission Electron Microscopy. Anti-corrosion against copper metal was studied in the occurrence of a highly corrosive aerobic bacterium B. thuringiensis EN2, Terribacillus aidingensis EN3, and Bacillus oleronius EN respectively. The results reveal that mixed consortium forms a thick biofilm on the metal surface and the weight loss (WL) was significantly increased to 0.041 ± 2 g when compared to aBiotic System (0.014 ± 1 g). In contrast, inhibitor System WL was reduced about 0.004 ± 1 g than Biotic System. For further confirmation of the above results, Surface analysis and EIS result revealed that the ZnONPs has inhibited the corrosive bacterial biofilm. This is the first description disclosing the application of myco-synthesized ZnONPs as effective anti-corrosive inhibitors against microbial influenced corrosion.

  • control of corrosive bacterial community by bronopol in industrial water System
    3 Biotech, 2018
    Co-Authors: Jayaraman Narenkumar, N. Ramesh, Aruliah Rajasekar
    Abstract:

    Ten aerobic corrosive bacterial strains were isolated from a cooling tower water System (CWS) which were identified based on the biochemical characterization and 16S rRNA gene sequencing. Out of them, dominant corrosion-causing bacteria, namely, Bacillus thuringiensis EN2, Terribacillus aidingensis EN3, and Bacillus oleronius EN9, were selected for biocorrosion studies on mild steel 1010 (MS) in a CWS. The biocorrosion behaviour of EN2, EN3, and EN9 strains was studied using immersion test (weight loss method), electrochemical analysis, and surface analysis. To address the corrosion problems, an anti-corrosive study using a biocide, bronopol was also demonstrated. Scanning electron microscopy and Fourier-transform infrared spectroscopy analyses of the MS coupons with biofilm developed after exposure to CWS confirmed the accumulation of extracellular polymeric substances and revealed that biofilms was formed as microcolonies, which subsequently cause pitting corrosion. In contrast, the biocide System, no pitting type of corrosion, was observed and weight loss was reduced about 32 ± 2 mg over Biotic System (286 ± 2 mg). FTIR results confirmed the adsorption of bronopol on the MS metal surface as protective layer (co-ordination of NH2–Fe3+) to prevent the biofilm formation and inhibit the corrosive chemical compounds and thus led to reduction of corrosion rate (10 ± 1 mm/year). Overall, the results from WL, EIS, SEM, XRD, and FTIR concluded that bronopol was identified as effective biocide and corrosion inhibitor which controls the both chemical and biocorrosion of MS in CWS.

  • Role of calcium-depositing bacteria Agrobacterium tumefaciens and its influence on corrosion of different engineering metals used in cooling water System.
    3 Biotech, 2017
    Co-Authors: Jayaraman Narenkumar, Kuppusamy Sathishkumar, A. Selvi, Rajagopalan Gobinath, Kadarkarai Murugan, Aruliah Rajasekar
    Abstract:

    The present investigation deals with the role of calcium-depositing bacterial community on corrosion of various engineering metals, namely, brass alloy (BS), copper (Cu), stainless steel (SS) and mild steel (MS). Based on the corrosion behavior, Agrobacterium tumefaciens EN13, an aerobic bacterium is identified as calcium-depositing bacteria on engineering metals. The results of the study are supported with biochemical characterization, 16S rRNA gene sequencing, calcium quantification, weight loss, electrochemical (impedance and polarization) and surface analysis (XRD and FTIR) studies. The calcium quantification study showed carbonate precipitation in aBiotic System/Biotic System as 50 and 700 ppm, respectively. FTIR results too confirmed the accumulation of calcium deposits from the environment on the metal surface by EN13. Electrochemical studies too supported the corrosion mechanism by showing a significant increase in the charge transfer resistance (Rct) of aBiotic System (44, 33.6, 45, 29.6 Ω cm2) than compared to Biotic System (41, 10.1 29 and 25 Ω cm2). Hence, the outcome of the present study confirmed the enhanced bioaccumulation behavior of calcium by the strain, EN13.

  • ginger extract as green biocide to control microbial corrosion of mild steel
    3 Biotech, 2017
    Co-Authors: Jayaraman Narenkumar, Ayyakkannu Usha Raja Nanthini, Kadarkarai Murugan, Punniyakotti Parthipan, Giovanni Benelli, Aruliah Rajasekar
    Abstract:

    In latest years, various techniques and chemicals have been used for the control of microbial influenced corrosion (MIC) of metals. The application of botanical-based biocides is one of the effective and practical techniques in the fight against MIC. In the present study, the role of aqueous extract of ginger (Zingiber officinale) (GIE) as green biocide to control MIC of mild steel 1010 (MS) in a cooling water System was investigated. Biocorrosion behavior of Bacillus thuringiensis EN2 on MS and its control by GIE was analyzed by electrochemical measurements. Polarization, electrochemical studies (ES), weight loss measurements (WL), and surface analysis (XRD, X-ray diffraction spectroscopy, and FTIR, Fourier transform infra-red spectroscopy) were performed under various incubation periods up to 4 weeks. We observed that EN2 forms a thick biofilm on the MS metal surface at the end of the incubation period and the WL significantly increased to 993 mg at fourth week when compared to the initial immersion period (194 ± 2 mg). In contrast, with addition of GIE, WL was reduced about 41 ± 2 mg over Biotic System (993 ± 2 mg). GC–MS analysis confirmed the adsorption of active component of GIE (β-turmerone) on the metal surface as a protective layer to prevent the biofilm formation and thus leads to reduction of corrosion. The optimum 20 ppm of GIE was found to be effective corrosion inhibition efficiency which was about 80%. From the results of WL, ES, XRD, FTIR, and GC–MS, GIE was identified as biocide and thus inhibits the bacterial growth on MS metal surface and it leads to control MIC. XRD showed that the GIE with EN2 resulted in less formation of corrosion products over Biotic and aBiotic Systems. Overall, this research first shed light on the antibacterial activity of GIE inhibiting biofilm formation, thus reducing the corrosion of MS in cooling water Systems.

Fashang Chen - One of the best experts on this subject based on the ideXlab platform.

  • comparative study on Biotic System and aBiotic System of marmatite at high cupric ions concentration
    Journal of materials research and technology, 2020
    Co-Authors: Hongbo Zhao, Ziliang Liu, Xiaoyu Meng, Wenqing Liu, Qinglei Jia, Yansheng Zhang, Lixin Liu, Fashang Chen
    Abstract:

    Summary This work investigated the behavior and mechanism of Cu2+ in marmatite Biotic System and aBiotic System. The leaching experiments show that the high cupric ions concentration (5 g/L) had obvious isolation both in Biotic System and aBiotic System in the early stage, the barrier effect gradually disappeared in Biotic System. X-ray photoelectron spectroscopy and electrochemical methods indicate that isolation substances were formed on marmatite surface in the presence of high cupric ions concentration (5 g/L), which may be CuxSy. However, the isolation substances were eliminated in Biotic System. Meanwhile, polysulfides and other substances were produced. The effect of these newly generated substances by bacteria on the surface oxidation of the marmatite remains to be explored.

Jayaraman Narenkumar - One of the best experts on this subject based on the ideXlab platform.

  • Myco-Synthesis of Zinc Oxide Nanoparticles as Potent Anti-corrosion of Copper in Cooling Towers
    Journal of Cluster Science, 2019
    Co-Authors: Parameswaran Sujatha Preethi, Arumugam Arul Prakash, Subramani Abilaji, Chandar Prakash, Ayyakkannu Usha Raja Nanthini, Jayaraman Narenkumar, Aruliah Rajasekar, Gurusamy Valli
    Abstract:

    This study demonstrated that, myco-synthesis of zinc oxide nanoparticles (ZnONPs) using the aqueous extract of button mushroom ( Agarius bisporus ) as a reducing agent. The nanoparticle formation was evaluated by UV–visible spectroscopy, Fourier Transform-Infrared spectroscopy, X-ray Diffraction spectroscopy, Energy Dispersive X-ray spectroscopy, and Transmission Electron Microscopy. Anti-corrosion against copper metal was studied in the occurrence of a highly corrosive aerobic bacterium B. thuringiensis EN2, Terribacillus aidingensis EN3, and Bacillus oleronius EN respectively. The results reveal that mixed consortium forms a thick biofilm on the metal surface and the weight loss (WL) was significantly increased to 0.041 ± 2 g when compared to aBiotic System (0.014 ± 1 g). In contrast, inhibitor System WL was reduced about 0.004 ± 1 g than Biotic System. For further confirmation of the above results, Surface analysis and EIS result revealed that the ZnONPs has inhibited the corrosive bacterial biofilm. This is the first description disclosing the application of myco-synthesized ZnONPs as effective anti-corrosive inhibitors against microbial influenced corrosion.

  • control of corrosive bacterial community by bronopol in industrial water System
    3 Biotech, 2018
    Co-Authors: Jayaraman Narenkumar, N. Ramesh, Aruliah Rajasekar
    Abstract:

    Ten aerobic corrosive bacterial strains were isolated from a cooling tower water System (CWS) which were identified based on the biochemical characterization and 16S rRNA gene sequencing. Out of them, dominant corrosion-causing bacteria, namely, Bacillus thuringiensis EN2, Terribacillus aidingensis EN3, and Bacillus oleronius EN9, were selected for biocorrosion studies on mild steel 1010 (MS) in a CWS. The biocorrosion behaviour of EN2, EN3, and EN9 strains was studied using immersion test (weight loss method), electrochemical analysis, and surface analysis. To address the corrosion problems, an anti-corrosive study using a biocide, bronopol was also demonstrated. Scanning electron microscopy and Fourier-transform infrared spectroscopy analyses of the MS coupons with biofilm developed after exposure to CWS confirmed the accumulation of extracellular polymeric substances and revealed that biofilms was formed as microcolonies, which subsequently cause pitting corrosion. In contrast, the biocide System, no pitting type of corrosion, was observed and weight loss was reduced about 32 ± 2 mg over Biotic System (286 ± 2 mg). FTIR results confirmed the adsorption of bronopol on the MS metal surface as protective layer (co-ordination of NH2–Fe3+) to prevent the biofilm formation and inhibit the corrosive chemical compounds and thus led to reduction of corrosion rate (10 ± 1 mm/year). Overall, the results from WL, EIS, SEM, XRD, and FTIR concluded that bronopol was identified as effective biocide and corrosion inhibitor which controls the both chemical and biocorrosion of MS in CWS.

  • Role of calcium-depositing bacteria Agrobacterium tumefaciens and its influence on corrosion of different engineering metals used in cooling water System.
    3 Biotech, 2017
    Co-Authors: Jayaraman Narenkumar, Kuppusamy Sathishkumar, A. Selvi, Rajagopalan Gobinath, Kadarkarai Murugan, Aruliah Rajasekar
    Abstract:

    The present investigation deals with the role of calcium-depositing bacterial community on corrosion of various engineering metals, namely, brass alloy (BS), copper (Cu), stainless steel (SS) and mild steel (MS). Based on the corrosion behavior, Agrobacterium tumefaciens EN13, an aerobic bacterium is identified as calcium-depositing bacteria on engineering metals. The results of the study are supported with biochemical characterization, 16S rRNA gene sequencing, calcium quantification, weight loss, electrochemical (impedance and polarization) and surface analysis (XRD and FTIR) studies. The calcium quantification study showed carbonate precipitation in aBiotic System/Biotic System as 50 and 700 ppm, respectively. FTIR results too confirmed the accumulation of calcium deposits from the environment on the metal surface by EN13. Electrochemical studies too supported the corrosion mechanism by showing a significant increase in the charge transfer resistance (Rct) of aBiotic System (44, 33.6, 45, 29.6 Ω cm2) than compared to Biotic System (41, 10.1 29 and 25 Ω cm2). Hence, the outcome of the present study confirmed the enhanced bioaccumulation behavior of calcium by the strain, EN13.

  • ginger extract as green biocide to control microbial corrosion of mild steel
    3 Biotech, 2017
    Co-Authors: Jayaraman Narenkumar, Ayyakkannu Usha Raja Nanthini, Kadarkarai Murugan, Punniyakotti Parthipan, Giovanni Benelli, Aruliah Rajasekar
    Abstract:

    In latest years, various techniques and chemicals have been used for the control of microbial influenced corrosion (MIC) of metals. The application of botanical-based biocides is one of the effective and practical techniques in the fight against MIC. In the present study, the role of aqueous extract of ginger (Zingiber officinale) (GIE) as green biocide to control MIC of mild steel 1010 (MS) in a cooling water System was investigated. Biocorrosion behavior of Bacillus thuringiensis EN2 on MS and its control by GIE was analyzed by electrochemical measurements. Polarization, electrochemical studies (ES), weight loss measurements (WL), and surface analysis (XRD, X-ray diffraction spectroscopy, and FTIR, Fourier transform infra-red spectroscopy) were performed under various incubation periods up to 4 weeks. We observed that EN2 forms a thick biofilm on the MS metal surface at the end of the incubation period and the WL significantly increased to 993 mg at fourth week when compared to the initial immersion period (194 ± 2 mg). In contrast, with addition of GIE, WL was reduced about 41 ± 2 mg over Biotic System (993 ± 2 mg). GC–MS analysis confirmed the adsorption of active component of GIE (β-turmerone) on the metal surface as a protective layer to prevent the biofilm formation and thus leads to reduction of corrosion. The optimum 20 ppm of GIE was found to be effective corrosion inhibition efficiency which was about 80%. From the results of WL, ES, XRD, FTIR, and GC–MS, GIE was identified as biocide and thus inhibits the bacterial growth on MS metal surface and it leads to control MIC. XRD showed that the GIE with EN2 resulted in less formation of corrosion products over Biotic and aBiotic Systems. Overall, this research first shed light on the antibacterial activity of GIE inhibiting biofilm formation, thus reducing the corrosion of MS in cooling water Systems.