Department Of Environmental Science And Technology
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Item A novel CaO nanocomposite cross linked graphene oxide for Cr(VI) removal and sensing from wastewater(Elsevier Ltd, 2022-04-27T00:00:00) Singh, Simranjeet; Naik, T.S. Sunil Kumar; Anil, Amith G.; Khasnabis, Sutripto; Nath, Bidisha; U, Basavaraju; Kumar, Vineet; Garg, V.K.; Subramanian, S.; Singh, Joginder; Ramamurthy, Praveen C.A novel green nanocomposite has been prepared by immobilizing CaO nanoparticles (CaO NPs) on the surface of graphene oxide. Biogenic CaO-NPs were synthesized from Lala clamshells. Morphological and structural characterizations of the nanocomposite were studied extensively. The adsorption capacity (qmax) of the nanocomposite for removing Cr(VI) was 38.04 mg g?1. In addition to this, the adsorption data were adequately simulated with Langmuir, Freundlich, Temkin, and pseudo-second-order models, suggesting that the adsorption process was the combination of external mass transfer and chemisorption. Electrostatic interaction was the dominant mechanism for Cr(VI) removal. In addition, the synthesized nanocomposites also serve as an excellent sensor for Cr(VI) sensing, with a limit of detection (LOD) of 0.02 ?M utilizing electrochemical methods. Therefore, this green nanocomposite can simultaneously serve as an adsorbent and sensor for Cr(VI)removal from aqueous solutions. � 2022 Elsevier LtdItem Application of EDTA modified Fe3O4/sawdust carbon nanocomposites to ameliorate methylene blue and brilliant green dye laden water(Academic Press, 2019) Kataria, N; Garg, V.K.This work explored the potential of magnetic sawdust carbon nanocomposites for cationic dyes removal from aqueous medium. EDTA modified magnetic sawdust carbon nanocomposites (EDTA@Fe3O4/SC ncs) were prepared by biogenic green reduction and precipitation approach. The surface properties, structure and composition of nanocomposites were characterized by HRTEM, FESEM, XRD, EDX, BET, FTIR etc. The Fe3O4 nanoparticles were 10–20 nm in diameters and having 14 m2/g surface area. Removal of Methylene blue (MB) and Brilliant green (BG) dyes from aqueous medium was studied in batch mode experiments. The maximum removal was achieved at neutral pH 7.0 with in 30 min. Adsorption capacity of EDTA@Fe3O4/SC for MB and BG dyes was 227.3 mg/g and 285.7 mg/g, respectively. Dye adsorption behaviour is well explained by Freundlich model. The rate of cationic dye adsorption is explained by pseudo-second order model. The value of thermodynamic parameters confirmed that adsorption process was spontaneous and favourable. Desorption and reusable efficiency of nanocomposites was also evaluated. © 2019 Elsevier Inc.Item Removal of Methylene Blue from aqueous solution by Fe3O4@Ag/SiO2 nanospheres: Synthesis, characterization and adsorption performance(Elsevier B.V., 2018) Saini, J.; Garg, V.K.; Gupta, R.K.In this study, silver silica coated magnetite (Fe3O4@Ag/SiO2) nanospheres were synthesized employing sonication method and their performance was evaluated as nanoadsorbents for the removal of Methylene Blue in batch mode experiments. The physical characteristics of these nanospheres were studied using XRD, SEM, EDX, TEM, and FTIR techniques. The Fe3O4@Ag/SiO2 nanospheres were capable to remove 99.6% Methylene Blue from aqueous solution at pH 7. A possible mechanism for the adsorption of Methylene Blue onto Fe3O4@Ag/SiO2 has been proposed. The adsorption equilibrium and kinetics were studied for experimental data. The removal process followed Langmuir isotherm with maximum monolayer adsorption capacity of 128.5 mg/g. Experimental kinetic data fitted well to Pseudo-second-order and Intraparticle diffusion models. The values of thermodynamic parameters, viz., ?G0, ?S0 and ?H0 confirmed spontaneous, endothermic and feasible adsorption of Methylene Blue under studied experimental conditions. The Fe3O4@Ag/SiO2 nanospheres were regeneratable and reusable for five successive cycles. ? 2017 Elsevier B.V.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 Japan