Faculty Publications

Now showing 1 - 4 of 4

Developing a biocatalyst showcasing the synergistic effect of rice husk biochar and bacterial cells for the removal of heavy metals
(Royal Society of Chemistry, 2023) Manikandan, S.K.; Nair, V.
Heavy metals like cadmium (Cd) and nickel (Ni) are toxic pollutants that affect the environment and pose health risks. Removal of Cd and Ni through bioremediation in the presence of biochar is a sustainable strategy. This study investigated the removal of Cd and Ni by Pseudomonas stutzeri immobilized on rice husk biochar (PRHB). The removal efficiency was calculated by varying the culture incubation time, pH, temperature, biocatalyst dosage, and initial metal ion concentration. PRHB showed a maximum metal removal capacity of 95% Cd and 92% Ni. The removal efficiency of PRHB was higher than that of free cells, which could be attributed to simultaneous adsorption, ion exchange, complexation, precipitation, and bioaccumulation caused by the biochar carrier and bacteria. The rice husk biochar material served as both an adsorbent and a carrier supplying nutrients for the growth of the bacteria. Considering the excellent metal ion removal capability and reusability, the use of PRHB could be a promising, cost-effective, and environment-friendly strategy for treating wastewater containing heavy metals. © 2023 The Royal Society of Chemistry.
Methyl orange dye adsorbed biochar as a potential Brønsted acid catalyst for microwave-assisted biodiesel production
(Springer, 2023) Chellappan, S.; Aparna, A.; Sajith, S.; Nair, V.; Chinglenthoiba, C.
Biodiesel production from non-edible oils utilizing a highly efficient eco-friendly catalyst is a crucial necessity for replacing fossil fuels. In the present work, biochar has been applied for both energy and environmental purposes. The biochar was made by slow pyrolysis from a variety of biomass, primarily cassava peel, irul wood sawdust, and coconut shell. All biochars were used as adsorbents to remove an anionic dye (methyl orange) by conducting batch adsorption studies. The biochar made from cassava peels showed the highest dye adsorption, and it was characterized using elements analysis (CHNS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area analyzer (BET), total acid density, and sulfonic acid group density to successfully confirm the presence of weak (–OH) and strong (–COOH, –SO3H) acidic groups. Furthermore, for microwave-assisted biodiesel production from Millettia pinnata seed oil, the dye adsorbed biochar made from cassava peel was utilized as a Brønsted acid catalyst. The catalyst having a surface area of 4.89 m2/g, an average pore width of 108.77 nm, a total acid density of 3.2 mmol/g, and a sulfonic acid group density of 1.9 mmol/g exhibits distinctive mesoporous properties that contribute to a biodiesel yield of 91.25%. By utilizing the catalyst for three more cycles and getting a yield of more than 75%, the reusability of the catalyst was investigated. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Combination of ensemble machine learning models in photocatalytic studies using nano TiO2 - Lignin based biochar
(Elsevier Ltd, 2024) K C, A.; Sankar Rao, C.; Nair, V.
Synergizing photocatalytic reactions with machine learning methods can effectively optimize and automate the remediation of pollutants. In this work, commercial Degussa TiO2 nanoparticles and lignin based biochar (LB) where used to prepare TiO2: lignin based biochar (TLB) composites using ultrasound-assisted co-precipitation method. The photocatalytic property of the TLB composites where studied by conducting the photocatalytic degradation of a Basic blue 41 (BB41) dye. The influence of calcination temperature, T:LB compositions, catalyst dosage, initial dye pH, initial dye concentration, and illumination time on photocatalytic dye degradation were experimentally studied. The degradation efficiency of 96.72 % was obtained under optimized conditions for the photocatalyst calcined at 500 °C containing a 1:1 wt percentage of TiO2 and LB. The experimental data was further used to predict the photocatalytic degradation efficiency using Gradient Tree Boosting (GTB) and Extra Trees (ET) models. The GTB model gave the highest prediction accuracy of 94 %. The permutation variable importance revealed catalyst dosage and dye concentration as the most influential parameters in the prediction of the photocatalytic dye degradation efficiency. © 2024 Elsevier Ltd
Mechanistic studies on bioremediation of dye using Aeromonas veronii immobilized peanut shell biochar
(Academic Press Inc., 2024) Singh, A.; Manikandan, S.K.; Nair, V.
Recalcitrant chemicals in the environment not only present obstacles to living organisms but also contribute to the degradation of natural resources. One contribution to environmental pollution is the discharge of synthetic dyes from the textile sector. This study investigates the combined effect of microbial cells and biochar on eliminating methyl orange (MO) dye. The immobilization of Aeromonas veronii on peanut shell biochar (APSB) was conducted to investigate its efficacy in removing MO dye from water. PSB synthesized by pyrolysis at 300 °C for 120 min showed maximum bacterial immobilization potential. The highest degradation rate of 96.19 % was achieved in APSB within 96 h using MO dye concentration of 100 mg L?1, incubation temperature of 37 °C, pH 7, and biocatalyst dosage of 1g L?1. In comparison, free cells achieved degradation rates of 72.53 % and 61.56 % for PSB. Moreover, the adsorption process was primarily controlled by PSB, with subsequent dye mineralization by A. veronii, as supported by FTIR and LC-MS studies. Moreover, this innovative approach exhibited the reusability of the biocatalyst, giving 76.23 % removal after fifth cycle, suggesting sustainable alternative in dye remediation and potential option for real-time applications. © 2024 Elsevier Inc.

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