School Of Environment And Earth Sciences

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    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 Ltd
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    Green synthesis, activation and functionalization of adsorbents for dye sequestration
    (Springer, 2019) Mudhoo, A; Gautam, R.K; Ncibi, M.C; Zhao, F; Garg, V.K; Sillanpää, M.
    The release of recalcitrant dyes into the biosphere is a threat because of pollution and environmental health issues. Adsorption using commercial activated carbon has been effective in industrial dye-loaded effluent remediation to some acceptable extent. However, commercial activated carbon suffers from limitations related to cost, relatively lower adsorption capacity, fewer microporous and mesoporous networks in comparison with other competing adsorbents, and reduced adsorption efficiency after regeneration. Here we review the recent developments in applying microwave irradiation, ultrasonication, ionic liquids and nanoscience for the preparation, activation, and physical, chemical and biological functionalization of novel and more potent adsorbents such as metal, mineral, carbon and polymer-based nanoparticles for dye removal. We observed that microwave and ultrasound irradiation and the use of ionic liquids are highly beneficial for the preparation of adsorbent materials; those adsorbents display enhanced porous structures and morphologies that account for much larger surface areas for faster adsorption interactions. Graphene-based, magnetic, cellulose-based and nanocomposite adsorbents are more selective and thermally more stable, faster in dye adsorption kinetics, have higher adsorption capacities for many dyes and can be regenerated for reuse without significant decrease in adsorption capacity. The scales of fabrication of green adsorbents do not go beyond the kilogram scale. © 2018, Springer Nature Switzerland AG.
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    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.