Department Of Environmental Science And Technology
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Item 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.Item 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, KnThe 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.Item 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.Item Removal of Congo red and Brilliant green dyes from aqueous solution using flower shaped ZnO nanoparticles(Elsevier Ltd, 2017) Kataria, N.; Garg, V.K.This work reports preparation and characterization of ZnO nanoparticles prepared by low temperature hydrothermal methods and their application for anionic dye (Congo red) and cationic dye (Brilliant green) removal from aqueous medium. The adsorption capacity of ZnO nanoparticles for Congo red dye and Brilliant green dye was up to 71.4 and 238 mg/g, respectively under selected process conditions. Dye adsorption behaviour has been explained applying different isotherms. Freundlich isotherm model best fitted to the dye removal data. Adsorption kinetics of both dyes is well explained by pseudo-second order model. Physical adsorption has been investigated using thermodynamic parameters viz., Gibb's free energy (?G?), enthalpy (?H?) and entropy (?S?). The reusability of ZnO nanoparticles was examined upto three cycles. ? 2017 Elsevier Ltd. All rights reserved.Item Removal of Orange G and Rhodamine B dyes from aqueous system using hydrothermally synthesized zinc oxide loaded activated carbon (ZnO-AC)(Elsevier Ltd, 2017) Saini, J.; Garg, V.K.; Gupta, R.K.; Kataria, N.This study reports the synthesis of zinc oxide loaded activated carbon (ZnO-AC) using hydrothermal method and its use to remove organic dyes [Orange G (OG) and Rhodamine B (Rh-B)] from the aqueous system under varying process conditions. ZnO-AC nanoparticles were characterized using XRD, SEM, EDX, DLS, and FTIR. The Langmuir adsorption model was best fitted to the experimental data for both the dyes. Langmuir adsorption capacity (qmax) for OG and Rh-B was 153.8 and 128.2 mg/g, respectively. The rate of adsorption was investigated by various models namely pseudo-first-order, pseudo-second-order and intraparticle diffusion model. Rate mechanism was described by pseudo-second-order model for both the dyes. Thermodynamic studies suggested that removal of Rh-B onto ZnO-AC was endothermic up to a temperature of 40 ?C while OG removal decreased with increase in temperature. Negative values of ? G0 for adsorption of dyes suggested spontaneous adsorption processes. ? 2017 Elsevier Ltd. All rights reserved.Item Preparation, characterization and potential use of flower shaped Zinc oxide nanoparticles (ZON) for the adsorption of Victoria Blue B dye from aqueous solution(Elsevier B.V., 2016) Kataria, N.; Garg, V.K.; Jain, M.; Kadirvelu, K.In present work, the performance and effectiveness of flower-shaped Zinc oxide nanoparticles (ZON) synthesised by hydrothermal method was evaluated for the adsorption of Victoria Blue B (VB B) dye from aqueous solution. ZON were characterised by using XRD, FTIR, SEM, EDX and DLS. Batch mode adsorption experiments were carried out to optimise the process conditions viz., pH, adsorbent dose, dye concentration, temperature, etc. The adsorption of cationic dye onto ZON surface was illustrated by Langmuir and Temkin isotherm models. The mechanism of dye adsorption onto the nanoparticles was explained by pseudo-second order kinetic model (R2???0.997). The thermodynamic parameters including Gibb's free energy (?G0), enthalpy (?H0), and entropy (?S0) were studied at different temperatures (10?70??C). The maximum adsorption capacity of VB B dye onto ZON was achieved up to 163?mg/g at pH 6.0 and temperature 27???1??C. ? 2016 The Society of Powder Technology JapanItem Comparative Analysis of Laccase Immobilization on Magnetic Iron Nanoparticles using Two Activating Agents:EDAC and Cyanuric Chloride(Tamil Nadu Scientific Research Organization (TNSRO), 2016) Das, Anamika; Singh, Jatinder; Yogalakshmi, K. N.Surface modification improves the covalent bonding of enzymes onto the magnetic nanoparticles. The present study aims to evaluate the effect of surface activators (EDAC (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide) and Cyanuric chloride) in immobilization of enzymes. Nanoparticles prepared by co-precipitation method ranged insize from 15-20 nm. The nanoparticles possessed crystalline property as confirmed by the XRD (X-ray powder diffraction) peaks. SEM-EDS (Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy) analysis of EDAC and cyanuric acid activated nanoparticles showed atomic sulphur percent of 0.08% and 0.02%, respectively. It is concluded that EDACwas more successful in loading more enzymes than cyanuric acid. Bradford estimation of the unbound protein after first wash for ENP-EDAC and ENP-CC was 29.1 μg/mL and 132.1 μg/mL, respectively. EDAC is a potential surface modifier for enzyme immobilization process.Item Laccase immobilized magnetic iron nanoparticles: Fabrication and its performance evaluation in chlorpyrifos degradation(Elsevier Ltd, 2017) Das, A.; Singh, J.; Yogalakshmi, K.N.Chlorpyrifos degradation was studied using laccase immobilized on magnetic iron nanoparticles (CENPs). The magnetic iron nanoparticles (MNPs) prepared by co-precipitation method were characterized using Transmission electron microscopy (TEM), Scanning electron microscopy- Energy dispersive spectroscopy (SEM-EDS) and Thermogravimetric analysis (TGA). The size of the nanoparticles ranged between 10 and 15 nm. The MNPs were coated with chitosan, surface modified with carbodiimide (EDAC) immobilized with laccase enzymes. The chlorpyrifos degradation studies were performed in batch studies under constant shaking for a period of 12 h. Results of the study showed that laccase immobilized on magnetic iron nanoparticles were effective in degrading more than 99% chlorpyrifos in 12 h at pH 7 and 60 ?C. In the overall degradation percentage, MNPs contributed to 32.3% of chlorpyrifos removal while ENPs resulted in 58.8% chlorpyrifos degradation. Immobilization of enzyme decreased the overall activity of the free enzyme. The CENPs showed 95% activity after five repeated washing and hence possess good reusability potential. ? 2017 Elsevier Ltd