Department Of Environmental Science And Technology

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    Anode modification: An approach to improve power generation in microbial fuel cells (MFCs)
    (Elsevier, 2023-01-27T00:00:00) Rani, Gini; Jaswal, Vijay; Yogalakshmi, K.N.
    Global energy demand is continuously increasing and has become a matter of concern. At present, 86% of the energy demand are accomplished by fossil fuels, but these deliver harmful effects on the environment by releasing CO2 in the atmosphere. Contrary, though nonrenewable resources such as solar, wind, and bioenergy possess minimal carbon footprints, they suffer from limitations of higher installation cost, low efficiency, and complex operation system. Since the past two decades, a relatively new sustainable technology, the microbial fuel cells (MFCs) have emerged with potential to convert the bond energy of molecules present in organic/inorganic waste into electric energy with the help of microbes. The electricity produced through the release of electrons during microbial degradation of organic waste can be used to offset the running cost of wastewater treatment plants. The performance of the MFCs is influenced by a number of cofactors, viz. type of reactor, nature of feed, microbial consortia, electrode material, and mode of operation. Anode plays a significant role in the power enhancement. Across the globe, various research groups are working to enhance the efficiency and power output of anode through its modification using conductive polymers (polypyrrole and polyaniline), metal oxides, nanomaterials, and many others. MFC operated with the electrochemically reduced graphene oxide modified anode evidenced a power density enhanced by 17.5 times as compared to carbon cloth. In the past 5 years, power density ranging from 6.12 to 6119mWm?2 was observed with various modified anode. The chapter will throw light on anode materials popularly used in MFC, method/techniques used for its modification to enhance energy output and limitations that restrict its wide-scale application. � 2023 Elsevier Inc. All rights reserved.
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    Amino-functionalized Magnetic Iron Nanoparticles As a Carrier for Laccase Enzyme and Its Potential to Degrade Chlorpyrifos in Contaminated Soil: Fate and Kinetics
    (Springer Science and Business Media Deutschland GmbH, 2022-04-14T00:00:00) Das, Anamika; Yogalakshmi, Kn
    The present study utilizes the covalent-crosslinking method to immobilize the�laccase enzyme on magnetic iron nanoparticles�and further assess its potential in degrading�chlorpyrifos in pesticide spiked�soil. The soil texture analysis revealed the presence of clay, silt and sand accounting to�7.1%, 14.3%, and 78.6%, respectively. The degradation of chlorpyrifos in spiked soil�using laccase enzyme�immobilized�magnetic iron nanoparticles was measured for 60�days�in a batch process. The results revealed a gradual increase in degradation efficiency showing around�29.3%, 43.8%, 56.3%, and 67.3% at the 20th, 30th, 40th, and 50th day�of incubation. A maximum degradation of�83.6% was observed on the 60th day of incubation. Intermediate products 2,4-bis(1,1 dimethylethyl) phenol, 1,2 benzenedicarboxylic acid, bis(2-methyl propyl) ester�and�piperidine confirmed the degradation of chlorpyrifos in soil. The piperidine originated in the chromatogram between�20�40�days of incubation and diminished later. Chlorpyrifos degradation followed pseudo first-order kinetics with a R2 of 0.96. Further, the nanoparticles showed no negative�impact on soil bacterial population during the antibacterial assay. The study confirms the degradation of chlorpyrifos in contaminated soil using laccase-immobilized nanoparticles. � 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    Degradation of chlorpyrifos in soil using laccase immobilized iron oxide nanoparticles and their competent role in deterring the mobility of chlorpyrifos
    (Elsevier Ltd, 2020) Das A.; Jaswal V.; Yogalakshmi K.N.
    Covalent-immobilization of the laccase enzyme onto the iron oxide nanoparticles was achieved using N-(3-Dimethylaminopropyl)-N?-ethylcarbodiimide hydrochloride (EDAC) as cross-linkers. The presence of sulphur moeity in the laccase immobilized nanoparticles (LNPs) observed through Scanning Electron Microscopy- Energy dispersive X-ray spectroscopy (SEM-EDS) spectra confirmed the immobilization of laccase enzyme. The TEM analysis of iron oxide nanoparticles (FNPs), chitosan coated iron nanoparticles (CNPs) and laccase immobilized nanoparticles (LNPs) confirmed their sizes around 12, 15 and 20 nm, respectively. The effect of LNPs in degrading chlorpyrifos under field conditions was studied by simulating the conditions in a column. Column A, which was used as control showed more leaching of chlorpyrifos as compared to column B containing LNPs. The sorption coefficient (Kd) value obtained for control (column A) and LNPs containing column B were 21.6 and 112.3 L/kg, respectively. LNPs altered the Kd values of soil thereby showing lesser leaching potential. Higher the Kd value, lesser will be the leaching potential in the ground water. Copper in laccase enzyme resulted in hydrolysis of chlorpyrifos. Chitosan used for coating on FNPs and soil organic matter resulted in the adsoption of chlorpyrifos. Current results will allow a better assessment of the role of LNPs as a competent deterrent in chlorpyrifos mobility and degradation.