Faculty Publications
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Item Azadirachta indica leaves extract as inhibitor for microbial corrosion of copper by Arthrobacter sulfureus in neutral pH conditions-A remedy to blue green water problem(Taiwan Institute of Chemical Engineers, 2016) Swaroop, B.S.; Noyel Victoria, S.N.; Ramachandran, R.Copper corrosion by the action of aerobic A. sulfureus in neutral medium was investigated. The bacteria form biofilm and colonize on the copper metal surface resulting in corrosion leading to blue green colour water. A. indica (neem) leaf extract was found to be effective in inhibiting the growth of the bacteria and thus help in preventing the corrosion. The copper coupons immersed for different durations in media with and without neem leaf extract were tested for their weight loss to study the corrosion rate. The copper biocorrosion was also investigated using electrochemical impedance spectroscopy and potentiodynamic polarization studies. The morphology of the films formed on the metal surface in different media at different immersion times were studied using scanning electron microscopy. © 2016 Taiwan Institute of Chemical Engineers.Item Effect of Green synthesized iron nanoparticles by Azardirachta Indica in different proportions on antibacterial activity(Elsevier B.V., 2018) Devatha, C.P.; Jagadeesh, K.; Patil, M.Green synthesis of iron nanoparticles has accumulated an ultimate interest over the last few years to their distinctive properties, applicable in various fields of science and technology. In the present study, synthesis of iron nanoparticles using Azadirachta Indica leaf extract is performed. Different proportions of precursor (ferrous sulphate) to leaf extract were prepared by varying the volume quantity of leaf extract from 1:1 to 1:5. Their morphology, structure and size distribution is confirmed by Scanning Electron Microscope along with X-ray energy dispersive spectroscopy and Fourier Transform Infrared spectroscopy analysis. Presence of accountable polyphenols such as total phenolic content by Folin-Ciocalteau(FC) method (20 mg per gram of leaf extract) and gallic acid(0.280 mg/g), caffeic acid(0.278 mg/g) & catechin(0.532 mg/g) for synthesis conciliation and were quantified by High Performance Liquid Chromatography. Its performance is evaluated on treatment of petrochemical refinery waste water to assess Chemical Oxygen Demand(COD) and nitrate removal for different proportions. The performance of COD removal (77%) and nitrate removal(74%) for 1:5 on 5th day is observed to be efficient. To further study this effect, size of FeNPs formed and concentration of polyphenols were taken into consideration. Antibacterial activity of synthesized iron nanoparticles from AI leaf extract on bacteria (Escherichia Coli, Pseudomonas Aeruginosa, and Staphylococcus Aureus) is accomplished by well diffusion method. Size of FeNPs achieved for 1:2 ratio was 98–200 nm and for all proportions varying between 120 and 600 nm due to agglomeration enhanced bacterial decay. It was portrayed that there was an increase in the inhibition zone as the proportions increased from 1:2 to 1:5. Hence for the contact time of 48 h, 1:5 found to be effective in inhibiting more number of bacterial cells compared to other proportions. © 2017 Elsevier B.V.Item Synthesis of plant-based biogenic jarosite nanoparticles using Azadirachta indica and Eucalyptus gunni leaf extracts and its application in Fenton degradation of dicamba(Editorial Office of Water Science and Engineering, 2024) Bhaskar, S.; Manu, B.; Sreenivasa, M.Y.; Manoj, A.Bio-jarosite, an iron mineral synthesized biologically using bacteria, is a substitute for iron catalysts in the Fenton oxidation of organic pollutants. Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts, are highly recyclable, and can be treated efficiently. This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles synthesized with green methods using two distinct plant species: Azadirachta indica and Eucalyptus gunni. The focus was on the degradation of dicamba via Fenton oxidation. The synthesized nanoparticles exhibited different particle size, shape, surface area, and chemical composition characteristics. Both particles were effective in removing dicamba, with removal efficiencies of 96.8% for A. indica bio-jarosite iron nanoparticles (ABFeNPs) and 93.0% for E. gunni bio-jarosite iron nanoparticles (EBFeNPs) within 120 min of treatment. Increasing the catalyst dosage by 0.1 g/L resulted in 7.6% and 43.0% increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min−1 and 0.023 min−1, respectively, confirming their catalytic roles. Additionally, the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions. © 2023 Hohai UniversityItem Adsorption – Advanced oxidation process (AAOP) for the heavy metals and organic matter removal from leachate using combined filtration -Fenton's and Photo-Fenton's treatment(Academic Press, 2024) Bhaskar, B.; Shree K N, R.; Apoorva, A.; Marikunte Yanjarappa, S.Design of cost – effective filtration unit was carried out to evaluate the efficiency of different filter media made of locally available materials to treat raw leachate. Four different filter media laterites, peat, bagasse and a mixture of all were considered as study filter media for the removal of Zinc, Nickel, Copper and Lead from raw leachate. The reactor exhibited a significant removal efficiency when the three-filter media were combined as a combination. A removal rate of around 83.0% and 64.12% was found for nickel and copper, respectively, with a combined filter medium. The order of heavy metal removal varied depending on the kind of filter media used. For combined filter media, the sequence was Ni > Cu > Pb > Zn. For bagasse filter media, it was Pb > Cu > Zn > Ni. For peat filter media, it was Ni > Cu > Pb > Zn. For laterite filter media, it was Zn > Cu > Ni > Pb. Insignificant removal of heavy metals was observed with bagasse in the current investigation and hence is not recommended for use as a filter medium. Pre-treated leachate was subjected to Fenton's oxidation and UV-Fenton's oxidation for organic matter removal. Green synthesized bleached laterite iron nanoparticles were used as a catalyst in the Fenton treatment. COD removal of 80.0% and 85.0% was observed with 0.5 g/L of nano iron catalyst and 500 mg/L of H2O2 and 100 mg/L of H2O2 on Fenton's oxidation and UV-Fenton's oxidation respectively. The synthesized particles were demonstrated to possess a catalytic function in the reduction of COD. Both Fenton's oxidation and UV-Fenton's oxidation exhibit pseudo-first-order kinetics with linear regression. © 2024 Elsevier Ltd