Department Of Environmental Science And Technology
Permanent URI for this communityhttps://kr.cup.edu.in/handle/32116/84
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Item Spectroscopic, thermogravimetric and structural characterization analyses for comparing Municipal Solid Waste composts and vermicomposts stability and maturity(Elsevier Ltd, 2017) Soobhany, N.; Gunasee, S.; Rago, Y.P.; Joyram, H.; Raghoo, P.; Mohee, R.; Garg, V.K.This is the first-ever study of its kind for an extensive assessment and comparison of maturity indexes between compost and vermicompost that have been derived from Municipal Solid Waste (MSW). The spectroscopic (Fourier transform infrared spectroscopy: FT-IR), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and structural characterization (scanning electron microscope: SEM) were recorded. FT-IR spectra showed an increase in conversion of polysaccharides species and aliphatic methylene groups in vermicompost compared to compost as depicted from the variation of the intensity of the peaks. TG curves of final vermicompost showed a much lower mass loss when compared to compost, indicating higher stability in feedstock. SEM micrographs of the vermicompost reflected strong fragmentation of material than composts which revealed the extent of intra-structural degradation of MSW. These findings elucidate on a clear comparison between composts and vermicomposts in terms of maturity indexes for soil enhancement and in agriculture as organic fertilizer. - 2017 Elsevier LtdItem 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 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 Comparative analysis of vermicompost quality produced from rice straw and paper waste employing earthworm Eisenia fetida (Sav.)(Elsevier Ltd, 2018) Sharma, K.; Garg, V.K.Present study was undertaken to investigate the vermicomposting of two different organic wastes (rice straw and paper waste) employing, Eisenia fetida. Nine feedstocks were prepared with different ratios of wastes using cow dung as bulking substrate. After pre-composting, worms were allowed to feed on different feedstocks for 105 days under laboratory conditions. The results showed that NPK content was higher in the vermicompost. Heavy metal content was also higher in the vermicomposts. Whereas total organic carbon and C:N ratio were lower after vermicomposting, by 17.38?58.04% and 19?102% respectively. SEM images revealed changes in the morphology of vermicompost. Earthworm growth and reproduction was significant in different feedstocks except one containing 50% rice straw depicting that this ratio is not suitable for the earthworms. Results further demonstrated that proportion of bulking substrate affect the earthworm growth and reproduction. ? 2017 Elsevier LtdItem 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