Faculty Publications
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Item Green synthesis of iron nanoparticles using different leaf extracts for treatment of domestic waste water(Elsevier Ltd, 2016) Devatha, C.P.; Thalla, A.K.; Katte, S.Y.Green synthesis of iron nanoparticles being cost effective and ecofriendly treatment technique, is gaining importance nowadays. The aim of the present study is to prepare leaf extracts, precursor, and synthesis of iron nanoparticles and to evaluate its efficacy in treating domestic waste water. Synthesis of iron nanoparticles is done using various leaf extracts viz. Mangifera indica, Murraya Koenigii, Azadiracta indica, Magnolia champaca, and to check its potential for treating domestic waste water. Characterization of the synthesized iron nanoparticles is done by UV–Visible spectrophotometer, Scanning Electron Microscopy equipped with X-ray energy dispersive spectroscopy and Fourier Transform Infrared spectroscopy. The characterization results confirm the formation and presence of iron nanoparticles and biomolecules which could help in capping the nanoparticles. The effect of iron nanoparticles thus obtained is evaluated for simultaneous removal of total phosphates, ammonia nitrogen, and chemical oxygen demand. Among the different plant mediated synthesized iron nanoparticles, Azadiracta indica showed 98.08% of phosphate, 84.32% of ammonia nitrogen and 82.35% of chemical oxygen demand removal. Overall performance of Azadiracta indica synthesized iron nanoparticles showed satisfactory results compared to other leaf extracts for treating domestic waste water. © 2016 Elsevier LtdItem The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor(IWA Publishing, 2018) Manu, D.S.; Thalla, A.K.The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4þ-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 ?m. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides. © IWA Publishing 2018.Item Polymer-based immobilized Fe2O3–TiO2/PVP catalyst preparation method and the degradation of triclosan in treated greywater effluent by solar photocatalysis(Academic Press, 2021) Pragada, S.C.; Thalla, A.K.The present study involves a novel protocol to develop a ternary composite catalyst for an effective post-treatment technique for greywater. The ternary film of Fe2O3–TiO2/polyvinyl pyrrolidine (PVP) is coated on a glass tube using spray coating with annealing at 320 °C. The structure, thermal, microstructure, and surface properties of the coated film are characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Thermo Gravimetric Analysis (TGA). The scratch hardness of photocatalysts at different Fe2O3/TiO2 compositions is investigated based on the width measurement of scratch using FESEM analysis. Results show that at an optimum coating of 5% of Fe2O3/TiO2 composition catalytic film, the maximum scratch hardness (7.984 GPa) is obtained. Also, the photocatalyst has the highest cohesive bond strength and wearing resistance. The degradation of triclosan (TCS) in treated greywater, discharged from the anaerobic-aerobic treatment system, is investigated at a lab-scale using a solar photocatalytic reactor. The response surface analysis has been performed from the different sets of experimental trials for various optimal parameters. It is observed that the TCS degradation efficiency of 83.27% has resulted under optimum conditions. © 2021 Elsevier LtdItem Biodegradation properties and thermogravimetric analysis of 3D braided flax PLA textile composites(SAGE Publications Ltd, 2022) Kanakannavar, S.; Jeyaraj, J.; Thalla, A.K.; RAJESH, M.Recent advances in the development and application of bio-based (natural fiber and biopolymer) composites are gaining broad attention because the resulting polymer completely degrades and does not release harmful substances. In this study, natural fiber 3 D braided yarn textile PLA (Polylactic acid) bio-composites are developed by film sequencing followed by hot-press compression molding. Bio-deterioration and thermal stability of the composites are analysed for storage, machining, transportation, and in-service uses in different environmental conditions (compost and thermal). Composite samples with different fiber wt.% (0, 22, 44) are exposed to compost soil. Tensile testing is performed under different configurations to characterise the tensile properties. Prepared bio-composite specimens are evaluated for weight loss and reduction in tensile properties over soil burial time, to observe the rate of biodegradation of braided yarn textile bio-composites. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) is employed to analyse the biodegradability of the composites. To study the thermal stability of the prepared bio-composites thermogravimetric (TG) analysis is carried out. Results showed that biodegradability, tensile properties and thermal stability of the composites are enhanced significantly with the reinforcement of 3 D braided yarn fabric. © The Author(s) 2021.Item Synthesis of silver nanoparticles using Myristica fragrans seed shell: Assessment of antibacterial, antioxidant properties and photocatalytic degradation of dyes(Elsevier Ltd, 2023) Thomas, T.; Thalla, A.K.In this era, the research on nanoparticles has gained higher demand and found its applications in fields like medicine, textile, waste management and industries. In this study Myristica fragrans seed shells (agricultural waste) aqueous extract is utilised for synthesis of silver nanoparticles from silver nitrate. The characterisation study of synthesised nanoparticles was carried out using Small-angle X-ray scattering, X-ray diffraction, thermogravimetric analysis, zeta potential, Fourier-transform infrared spectroscopy, BET surface area analyser and field emission scanning electron microscope. UV–vis spectrophotometer analysis shows surface plasmonic resonance at 470 nm, confirming the formation of nanoparticles. The nanoparticles were in the range of 10–60 nm with a surface area of 88.16 m2/g. The present study analysed antibacterial (gram-positive and gram-negative bacteria) and antioxidant properties (DPPH and hydroxyl radicals) to prove the practical application of synthesised nanoparticles in the field of food processing. Best radical scavenging activity was observed at 200 μg/mL of nanoparticles. Further synthesised silver nanoparticles were used to study its feasibility in dye removal, and the results showed a better photocatalytic degradation (>90%) of rhodamine B (zwitterionic), remazol brilliant blue reactive (anionic) and methyl violet 10B (cationic) under UV light. The degradation mechanism follows the pseudo-first-order kinetic model and Langmuir isotherm model, which implies the dye degradation is influenced by the affinity of nanoparticles towards dye and their radical action. The degradation products are analysed using UPLC-MS and identified the degradation mechanism. © 2023 Elsevier LtdItem Bioprospecting indigenous bacteria from landfill leachate for enhanced polypropylene microplastics degradation(Elsevier B.V., 2025) Dubey, A.P.; Thalla, A.K.Plastic pollution, especially microplastics (MPs), is a severe environmental threat. Due to the significant environmental issues posed by plastics, it is critical to use an effective and sustainable degradation technique. The study aimed to isolate and identify Indigenous bacterial strains from landfill leachate (LL) to evaluate its potential for degrading Polypropylene microplastics (PPMPs). The investigation identified two bacterial strains, Pseudomonas aeruginosa, and novel Staphylococcus haemolyticus, through 16S rRNA analysis, capable of decomposing PPMPs. Following a 30-day treatment period, it was noted that Staphylococcus haemolyticus reduced the dry weight of PPMPs by 25.46 % ± 1.35 %, whereas Pseudomonas aeruginosa strain reduced it by 7.01 % ± 0.85 %. Multiple tests, including weight loss, pH, optical density, total biomass yield, and BATH test of the medium, validated the growth of bacterial strains. The biochemical characteristics of the isolated strains were assessed through Biochemical tests. The study also investigated the surface, chemical, and structural changes in treated PPMPs using Scanning electron microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), and Ion Chromatography (IC) tests. The Fourier Transform Infrared Spectroscopy (FTIR) study also showed the creation of alcohol, methyl, as well as carbonyl groups due to hydrolysis and oxidation by both bacterial strains. This study implies that the Staphylococcus haemolyticus and Pseudomonas aeruginosa bacterial strains are secure and efficient for PPMP bioremediation. © 2025 Elsevier B.V.Item A comprehensive study on quantification and characterization of microplastics in compost, landfill-soil and leachate(SAGE Publications Ltd, 2025) Dubey, A.P.; Thalla, A.K.Microplastics (MPs), a category of synthetic emerging pollutants, have been detected in various environmental matrices. This study assesses the abundance of MPs in the soil, wet compost (WC), Black soldier compost (BSC) and landfill leachate (LL) of the municipal solid waste management plant. Samples were pretreated with a Fenton reagent, followed by density separation and analysed using a digital portable microscope. They were then categorized based on their shape, colour and size to provide information on their distribution. The work reveals an average MP count of 7590?±?1004.092 MP kg?1in soil. MPs were 5900?±?565.69 MP kg?1for BSC, 11,350?±?353.55 MP kg?1for WC and LL samples 98.83?±?6.83 MP L?1. Notably, a significant proportion of MPs, 85% in soil, 86% in compost and 72.6% in LL, measured size less than 300?µm. Samples showed different proportions of fragments, microbeads and fibres, with white/transparent and black being the predominant colours of MPs. Additionally, the study identifies the physicochemical properties of the samples, and the polymer types are identified using attenuated total reflectance-Fourier transform infrared spectroscopy. The study revealed that polypropylene and polyethylene are the most abundant polymers in the samples, indicating that landfills serve as significant sources of MPs. The adopted MP extraction method was tested for its recovery efficiency, and the recovery rates for leachate, compost and soil were found to be 94.3%, 80% and 77.9%, respectively. This research offers insight into the types and abundance of MPs in southern India’s landfills, prompting further studies on detection methods. © The Author(s) 2025