Environmental Science And Technology - Research Publications
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Item Pb2+ and Cd2+ recovery from water using residual tea waste and SiO2@TW nanocomposites(Elsevier, 2020) Joshi, S; Kataria, N; Garg, V.K; Kadirvelu, K.This work reports the fabrication of SiO2@TW nanocomposites and their application for Pb2+ and Cd2+ ions sequestration from simulated water. Residual tea waste has also been used for metal ions sequestration to compare the potential of SiO2@TW nanocomposites. The SEM, TEM, BET, FTIR and EDX techniques were employed for the characterization of SiO2@TW nanocomposites and residual tea waste. Particle sizes of SiO2@TW nanocomposites was in the range of 6.8-12 nm. The experiments were carried out in batch mode to explore the effect of various operating parameters on the sequestration of Pb2+ and Cd2+ ions from water. The experimental data was subjected to various thermodynamic, kinetic and isothermic models. According to Langmuir model, the maximum adsorption efficiency of the SiO2@TW nanocomposites was 153 mg/g for Pb2+ and 222 mg/g for Cd2+ but maximum adsorption efficiency of residual tea waste for Pb2+ was 125 mg/g and for Cd2+ was 142.9 mg/g. This study suggested that due to the presence of active sites SiO2@TW nanocomposites has greater potential for metal sequestration than residual tea waste. 2020 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 JapanItem Removal of hexavalent chromium from aqueous solution using biomass derived fly ash from Waste-to- Energy power plant(Taylor & Francis, 2013) Vaid, Upma; Mittal, Sunil; Babu, J. NagendraFly ash from the agricultural waste-based Energy Power Plant has been studied for the adsorption of hexavalent chromium [Cr(VI)]. In order to maximize the Cr(VI) removal from simulated aqueous solutions, effects of various parameters i.e. adsorbent dose (10–40 g/L), contact time (5–90 min), variation in pH (1–5), and initial metal ion concentration (10–80 mg/L) on Cr(VI) adsorption were investigated by batch adsorption experiments. It was observed that adsorption of Cr(VI) on the selected adsorbent was dependent on pH. Before optimization of experimental conditions, the percent removal of Cr(VI) from the aqueous solution (10 mg Cr/L) was approximately 4%, which increased to approximately 99% after optimization of experimental conditions. Maximum adsorption was observed upon adding 10 g/L of adsorbent to a 60 mg Cr/L aqueous solution at pH 1.0 and contact time of 90 min at 200 rpm. Equilibrium adsorption data were well fitted in Langmuir isotherm model which substantiate monolayer adsorption of Cr(VI) on fly ash. Kinetics of Cr(VI) adsorption on fly ash follows pseudo-second-order reaction.Item Removal of hexavalent chromium from aqueous solution: a comparative study of cone biomass of “Picea smithiana” and activated charcoal(Taylor & Francis, 2016) Mittal, Sunil; Vaid, Upma; Najar, Gh Nabi; Babu, J. NagendraThe present work investigates comparative adsorption efficiency of powdered cone biomass of Picea smithiana (PCBP) and activated charcoal (AC) for removal of hexavalent chromium (Cr) (Cr(VI)) from aqueous solution. The study indicates that PCBP has 76% removal efficiency for Cr as compared to AC. Particle size and SEM-EDX analyses were done to determine average particle size, surface morphology and elemental composition of PCBP. BET and FTIR analysis were carried out to elucidate the adsorption mechanism of Cr(VI) on PCBP. Ashing has been proposed as a method for managing waste of loaded PCBP generated in adsorption. Ashing studies showed the ash content of PCBP to contribute only 13% of the ash generated from loaded biomass. Further, a comparative study has been made indicating the adsorption efficiency of PCBP with previously reported bio-waste materials. The results of this study show that PCBP has high adsorption efficiency as compared to other bio-waste materials.Item Influence of anion induced proton abstraction on Cu(II) adsorption by alginic acid(Elsevier B.V., 2015) Vaid, U.; Mittal, S.; Nagendra Babu, J.Alginic acid (AA) synthesized by acidification of commercial sodium alginate was investigated for its Cu(II) adsorption efficiency in the presence of different counter ions. The results of batch adsorption studies indicated an adsorption of 169.86 mg/g of Cu(II) by AA in the presence of acetate ions, however, it significantly decreased in the presence of chloride (126.36 mg/g), sulphate (115.24 mg/g) and nitrate (113.28 mg/g) as counter ions. This can be accounted to the tendency of conjugate base (anion) to abstract proton from AA, which determines the extent of deprotonation of carboxylic acid. The FTIR and TGA/DTA studies support the difference in the coordination of carboxylate to Cu(II) in the presence of various counter anions. Acetate showed strong chelate coordination between Cu(II) and AA, whereas in the presence of Cl-, NO3- and SO42 -, Cu(II) was complexed by weak bridging coordination with AA. � 2015 Elsevier B.V.