Faculty Publications
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Item Effective Usage of Biochar and Microorganisms for the Removal of Heavy Metal Ions and Pesticides(MDPI, 2023) Manikandan, S.K.; Pallavi, P.; Shetty K, V.; Bhattacharjee, D.; Giannakoudakis, D.A.; Katsoyiannis, I.A.; Nair, V.The bioremediation of heavy metal ions and pesticides is both cost-effective and environmentally friendly. Microbial remediation is considered superior to conventional abiotic remediation processes, due to its cost-effectiveness, decrement of biological and chemical sludge, selectivity toward specific metal ions, and high removal efficiency in dilute effluents. Immobilization technology using biochar as a carrier is one important approach for advancing microbial remediation. This article provides an overview of biochar-based materials, including their design and production strategies, physicochemical properties, and applications as adsorbents and support for microorganisms. Microorganisms that can cope with the various heavy metal ions and/or pesticides that enter the environment are also outlined in this review. Pesticide and heavy metal bioremediation can be influenced by microbial activity, pollutant bioavailability, and environmental factors, such as pH and temperature. Furthermore, by elucidating the interaction mechanisms, this paper summarizes the microbe-mediated remediation of heavy metals and pesticides. In this review, we also compile and discuss those works focusing on the study of various bioremediation strategies utilizing biochar and microorganisms and how the immobilized bacteria on biochar contribute to the improvement of bioremediation strategies. There is also a summary of the sources and harmful effects of pesticides and heavy metals. Finally, based on the research described above, this study outlines the future scope of this field. © 2023 by the authors.Item Floating bed reactor for visible light induced photocatalytic degradation of Acid Yellow 17 using polyaniline-TiO2 nanocomposites immobilized on polystyrene cubes(Springer, 2020) Nair, V.R.; Shetty K, V.In the present study, PANI-TiO2 nanocomposites have been used in suspended and immobilized form for photocatalytic degradation of Acid Yellow 17 (AY-17) dye under visible light. PANI-TiO2 nanocomposites were immobilized in polystyrene cubes to form PANI-TiO2 @ polystyrene cubes. The nanocomposites were found to be visible light active both in suspended and immobilized form. PANI-TiO2 nanocomposite with 13% TiO2 loading was found to be the optimum in terms of maximum degradation of AY-17. The efficiency of floating bed photoreactor (FBR) operated in liquid recycle mode using PANI-TiO2 @ polystyrene cubes was studied. In this reactor, around 89% degradation of 1 L of AY-17 with an initial concentration of 10 mg/L could be achieved with 2.83 g/L per pass of immobilized catalyst. The FBR operated with PANI-TiO2 @ polystyrene cubes has exhibited good performance as a photocatalytic reactor and may be recommended over other conventional photo reactors for treatment of wastewater contaminated with synthetic dyes. The kinetics of degradation of AY-17 by photocatalysis under visible light with suspended PANI-TiO2 and PANI-TiO2 @ polystyrene cubes followed first-order kinetics. The values of apparent kinetic parameter for degradation by immobilized photocatalysts are lower than the corresponding kinetic parameter for suspended photocatalysts. It confirms the existence of diffusional limitations in photocatalysis by PANI-TiO2 @polystyrene cubes. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Suspended and polycaprolactone immobilized Ag @TiO2/polyaniline nanocomposites for water disinfection and endotoxin degradation by visible and solar light-mediated photocatalysis(Springer Science and Business Media Deutschland GmbH, 2021) Gadgil, D.J.; Shetty K, V.In the present study, water contaminated with Escherichia coli (E. coli) cells was photocataytically disinfected using Ag core-TiO2 shell/Polyaniline nanocomposite (Ag@TiO2/PANI) under visible light irradiation. Ag@TiO2/PANI containing 13 weight % of Ag@TiO2 was found to offer maximum disinfection activity. Band gap energy of Ag@TiO2/PANI was found to be 2.58 eV. Ag@TiO2/PANI nanocomposites were efficient in water disinfection in their suspended and immobilized form. Rate of disinfection with Ag@TiO2/PANI was faster than that with Ag@TiO2 nanoparticles. Water containing 50 × 108 CFU/mL cells was completely disinfected within 120 min with 1 g/L Ag@TiO2/PANI nanocomposite. Simultaneous disinfection and endotoxins degradation were achieved. The photocatalytic disinfection of water and endotoxin degradation using Ag@TiO2/PANI nanocomposite under visible light irradiation followed second order kinetics. The nanocomposite also exhibited a good solar photocatalytic activity. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
