Browsing by Author "Garg V.K."

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    Application of EDTA modified Fe3O4/sawdust carbon nanocomposites to ameliorate methylene blue and brilliant green dye laden water
    (Academic Press Inc., 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.
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    Applications of Fe3O4@AC nanoparticles for dye removal from simulated wastewater
    (Elsevier Ltd, 2019) Joshi S.; Garg V.K.; Kataria N.; Kadirvelu K.
    This study deals with the removal of cationic dyes from the simulated wastewater using Fe3O4 nanoparticles loaded activated carbon. Fe3O4@AC nanoparticles were synthesised using co-precipitation methods. The Fe3O4@AC nanoparticles (nps) were characterised using different techniques and data revealed that the synthesised nanoparticles were 6–16 nm in diameter. pHpzc of Fe3O4@AC nanoparticles was 7.8. BET surface area of Fe3O4@AC nps was found to be 129.6 m2/g by single point method and 1061.9 m2/g by multipoint method. Adsorption experiments were performed to optimize the effect of process conditions such as pH of solution, nanoparticles dose, temperature, concentration of dye and contact time on contaminant removal. The maximum uptake capacity of Fe3O4@AC was found to be 138 and 166.6 mg/g for methylene blue and brilliant green dyes, respectively. In order to assess dye adsorption behaviour, adsorption isotherm models viz., Langmuir, Freundlich and Temkin were applied to the data. Langmuir isotherm best fitted [R2 = 0.993 (MB) and R2 = 0.920 (BG)] to the experimental data of both the dyes. Further, Pseudo-second order rate equation fitted better to the experimental data. Reuse potential of the nanoparticles was also investigated for the removal of both the dyes and it is inferred from the data that the synthesised nanoadsorbent has promising reuse potential, therefore can be used for several cycles.
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    Development of iron oxide/activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
    (Elsevier B.V., 2018) Jain M.; Yadav M.; Kohout T.; Lahtinen M.; Garg V.K.; Sillanp M.
    Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were highest by Fe3O4/AC for Cr(VI) = 0.9994,Cu(II) = 0.9998 and Cd(II)= 0.9750. The temperature dependent study in the range of 288–328 K confirmed that the adsorption process was endothermic in nature. Desorption studies with 0.1 M HCl stated that these nanoparticles can be regenerated effectively and can be used after four adsorption-desorption cycles without any mass loss.
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    Green fabrication of ZnO nanoparticles using Eucalyptus spp. leaves extract and their application in wastewater remediation
    (Elsevier Ltd, 2020) Chauhan A.K.; Kataria N.; Garg V.K.
    The present study explored removal of carcinogenic cationic and anionic dyes from aqueous medium using green fabricated zinc oxide nanoparticles (ZnO-NPs). The ZnO-NPs were synthesized employing biogenic green reduction and precipitation approach. The characterization of ZnO NPs was done using various techniques such as FESEM, XRD, BET, TGA, HRTEM, EDX, and FTIR. All experiments were conducted in batch mode. Maximum removal was achieved at pH 6.0 and pH 8.0 for Congo Red (CR) and Malachite Green (MG) dyes respectively. Dye adsorption process showed better fit with Langmuir and Temkin isotherm models for CR dye and MG dye respectively. Maximum adsorption capacity of ZnO NPs was 48.3 mg/g for CR dye and 169.5 mg/g for MG dye. The dye adsorption followed pseudo-second order model and values of thermodynamic parameters confirmed that the adsorption process was spontaneous and favourable. Reusability efficiency of the nanoparticle was explored using ethanol and water and based on results it was inferred that ZnO-NPs can be reused for dye removal. Effect of salinity on the removal of CR and MG dyes was also explored and found that presence of salinity in aqueous medium have adverse impact on the dye removal efficiency of ZnO-NPs.
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    Green synthesized SiO2@OPW nanocomposites for enhanced Lead (II) removal from water
    (Elsevier B.V., 2020) Saini J.; Garg V.K.; Gupta R.K.
    The orange peel waste (OPW) was chemically spiked with silica nanospheres, to develop a novel, nanocomposite (SiO2@OPW) with enhanced adsorption capacity for heavy metals. The dispersion of silica nanospheres into orange peel waste was confirmed by XRD, FTIR, TEM, SEM and EDX. Adsorption of Pb2+ ions onto SiO2@OPW was studied in batch mode under varying process conditions such as pH, metal concentration, contact time and adsorbent dosage. The maximum adsorption capacity for OPW and SiO2@OPW was 166.7 mg/g and 200.0 mg/g, respectively calculated employing the Langmuir isotherm model. The kinetic data followed pseudo second order and intraparticle diffusion models. The maximum removal of Pb2+ ions was at pH = 6.0, adsorbent dosage = 0.02 g/L and contact time 60 min. Regeneration and reusability of SiO2@OPW was studied for five cycles. Owing to reusability and high adsorption capacity, SiO2@OPW nanocomposites may be considered as a promising adsorbent for the removal of heavy metals from water and wastewater.
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    Natural Radioactivity in Soil, Associated Radiation Exposure and Cancer Risk to Population of Eastern Haryana, India
    (Geological Society of India, 2019) Daulta R.; Garg V.K.; Singh B.
    This study was undertaken to quantify the natural radioactivity in soil and associated radiation exposure to the inhabitants residing in Sonipat district, Haryana, India. A total of 120 soil samples were collected from 30 villages. These soil samples were quantified for naturally occurring radioactive materials activity using HPGe detector. Activity concentration of 40K, 232Th and 226Ra in the soil samples of study area ranged from 463.8�696.9 Bq kg?1, 31.4�37.9 Bq kg?1and 41.5�54.9 Bq kg?1, respectively. Radium equivalent (Raeq) values of all samples are lesser than maximum permissible limit (370 Bq kg�1) acceptable for safer use of soil as building material. Average value of Air absorbed dose (AAD) in the study area was comparable to the Indian average of 64 nGy h?1. Annual effective dose equivalent (AEDE) in the study area was 0.0831 �Sv y?1 that is lower than the global average of 70.0 �Sv y?1. Annual Gonadal equivalent dose in study area was within the safe limit (1 �Sv y?1). Excess life time cancer risk due to natural radioactivity of soil to population of area is negligibly small. Values of Gamma index (I�), outside hazard index (Hex) and inside hazard index (Hin) are less than unity, indicating that there is no considerable health risk caused by natural radioactivity in soil in the study area. � 2019, GEOL. SOC. INDIA.
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    Optimization of cadmium(II) removal from water using sunflower waste carbon-a statistical approach
    (Taylor and Francis Ltd, 2020) Jain M.; Garg V.K.; Paliwal R.; Kadirvelu K.; Chaudhry S.
    In this study, a statistical experimental strategy was used to optimize the Cd(II) adsorption by chemically treated stems of Helianthus annuus (sunflower). The maximum cadmium adsorption was found at 100 mg/L when a dose of 2000 mg/100 ml was applied at pH 6.0. The highest percentage removal obtained using the model was 100%. The F value (17.28), lack-of-fit value (0.09) and coefficient of determination (R2 = 0.939) established the appropriateness of quadratic model. The results of confirmation experiment, i.e. 99.8% removal of Cd(II) by prepared adsorbent under optimized conditions agreed well with the model predictions.
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    Optimization of Pb (II) and Cd (II) adsorption onto ZnO nanoflowers using central composite design: isotherms and kinetics modelling
    (Elsevier B.V., 2018) Kataria N.; Garg V.K.
    This study focused to optimization and screening of parameters for the adsorption of Cd (II) and Pb (II) onto ZnO nanoflowers. These were synthesized by low temperature hydrothermal methods. The surface properties of ZnO nanoflowers, before and after metal adsorption were characterized by FTIR, FESEM and EDX spectra. The adsorption parameters were optimized using central composites design. Adsorption behaviour and metals-adsorbent interaction was evaluated using batch mode experiments and isothermal models. Maximum adsorption capacity of ZnO nanoflowers was 71.5 mg/g and 115 mg/g for Cd (II) and Pb (II), respectively. In isotherms studies, Freundlich model is best fitted to metal adsorption data that indicated multilayer adsorption of Cd (II) and Pb (II) onto ZnO. The rate mechanism of metals ions adsorption was well explained by pseudo-second order models. The Adsorption efficiency of ZnO nanoflowers was analysed in spiked ground water sample also. The reusability of ZnO nanoflowers was also explored upto three cycles.
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    Vermicomposting of lignocellulosic waste: A biotechnological tool for waste management
    (CRC Press, 2017) Sharma K.; Garg V.K.
    Rapid urbanization and increment in global population have resulted in huge waste mass generation. A significant portion of solid waste is biodegradable in nature, of which a considerable fraction is lignocellulosic biomass. Lignocellulosic wastes are mainly generated by agricultural and industrial activities. Presently, this huge biomass has no gainful use and it is adding to environmental degradation. Several physical, chemical, and biological methods have been used for the management of lignocellulosic waste. These methods include landfilling, incineration, pyrolysis, gasification, recycling, material recovery, composting, and so on. But each method has its own limitations. Sustainable biological waste management methods are to protect environment and conserve natural resources. Vermicomposting is one such kind of organic matter management process. Lignocellulosic waste due to high biodegradability and moisture content are ideal feedstock for earthworms. Vermicomposting can be utilized for the conversion of lignocellulosic wastes into vermicompost and earthworm biomass. Various studies conducted on the management of lignocellulosic waste using vermicomposting are reviewed in this chapter.