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 Isolation and identification of Pseudomonas from wastewater, its immobilization in cellulose biopolymer and performance in degrading Triclosan(Academic Press, 2019) Devatha, C.P.; Narasimhappa, N.Triclosan (TCS) is a well-known emerging contaminant got wide use in daily use products of domestic purpose, which provides the way to enter the ecological cycle, and is preferably detected in sewage treatment plants. In this study, TCS degrading bacteria (TDB) was isolated and identified from a wastewater treatment plant at the National Institute of Technology-Karnataka, Surathkal (NITK), India. The isolate was reported as Pseudomonas strain by performing 16S RNA Sequencing using BLAST analysis. Bacterial growth depends upon several environmental factors. Hence its growth optimization was carried out by response surface method (RSM) based central composite design (CCD) and validated by the artificial neural network (ANN). The Parameters or inputs used for optimization are pH, time (days), agitation (rpm) and sorbent dosage (?g/L). Experiments were conducted in batch mode to achieve optimum growth of bacteria based on RSM trial runs. The RSM model predictions were in better agreement with the experimental results and it was confirmed by ANN. The deviation lies within ±10% with experimental results compared to ANN for maximum trials. Hence optimized parameters were established and arrived at pH - 7, time - 13 days, agitation - 150 rpm, dosage - 1.5 ?g/L presented 69% removal of TCS. Minimum inhibitory assay of isolated strain was conducted to identify the degradation capacity of TCS and it was found out to be lesser than 0.025 mg of TCS. Later the strain was immobilized in two different matrices. One is biopolymer extracted from cellulose (Water Hyacinth) along with sodium alginate and second is free bacteria with sodium alginate and was made in the form of beads. The removal of TCS by TDB-cellulose-alginate (BCA) and TDB-Alginate (BA) beads were 58% and 30% respectively. Hence it was concluded that BCA beads showed effective removal compared to BA beads. Therefore, isolate can degrade TCS when the concentration ranges from 0.025 mg/L to 5.5 ng/L. © 2018 Elsevier LtdItem Performance evaluation of horizontal and vertical flow constructed wetlands as tertiary treatment option for secondary effluents(Springer Verlag, 2019) Thalla, A.K.; Devatha, C.P.; Anagh, K.; Sony, E.Constructed wetlands (CWs) are simple low-cost wastewater treatment units that use natural process to improve the effluent water quality and make it possible for its reuse. In the present study, a comparison is made between horizontal subsurface flow (HSSF-CW) and vertical flow (VFCW) constructed wetland in effectively post-treating the effluents from the secondary biological treatment system. Locally available plants, viz. Pennisetum pedicellatum and Cyperus rotundus, which are abundantly available in the Western Ghats, were used in the wetland. A pilot-scale study was undertaken in National Institute of Technology, Karnataka Campus. The experiments were conducted at two hydraulic retention times, i.e., 12 h and 24 h. The experimental study was carried out in February 2018 to May 2018. Concentration-based average removal efficiencies for HSSF-CW and VFCW were BOD, 77% and 83%; COD, 60% and 65%; NH4 +–N, 67% and 84.47%; NO3–N, 69% and 66.75%; and PO4–P, 85% and 90%, respectively. VFCW showed a better overall removal efficiency than HSSF-CW by 7.14%. Thus, constructed wetland can be considered as a sustainable alternative to the tertiary conventional treatment of domestic wastewater, thus making it possible for reuse. © 2019, The Author(s).Item Experimental investigation for treating ibuprofen and triclosan by biosurfactant from domestic wastewater(Academic Press, 2023) Jayalatha, N.A.; Devatha, C.P.The presence of emerging pollutants of pharmaceutical products and personal care products (PPCPs) in the aquatic environment overspreads the threat on living beings. Bioremediation is a promising option for treating wastewater. In the present study, an experimental investigation was carried out to produce a biosurfactant by Pseudomonas aeruginosa (MTCC 1688) for the removal of Ibuprofen (IBU) and Triclosan (TCS) from domestic wastewater. It was performed in three stages. Firstly, the production and optimization of biosurfactant was carried out to arrive at the best combination of crude sunflower oil, sucrose and ammonium bicarbonate (10%: 5.5 g/L: 1 g/L) to yield effective biosurfactant production (crude biosurfactant) and further extended to achieve critical micelle concentration (CMC) formation by dilution (biosurfactant at 10.5%). The stability of the biosurfactant was also confirmed. Biosurfactant showed a reduction in the surface tension to 41 mN/m with a yield concentration of 11.2 g/L. Secondly, its effectiveness was evaluated for the removal of IBU and TCS from the domestic wastewater collected during the dry and rainy seasons. Complete removal of IBU was achieved at 36 h & 6 h and TCS at 6 h & 1 h by crude biosurfactant and biosurfactant at CMC formation for the dry season sample. IBU removal was achieved in 2 h by both crude and biosurfactant at CMC and no TCS was detected in the rainy season sample. Thirdly, biotransformation intermediates of IBU and TCS formed during the application of the biosurfactant and degradation pathways are proposed based on the Liquid Chromatography-Mass Spectrometry (LC-MS) and it indicates that there is no formation of toxic by-products. Based on the results, it is evident that biosurfactant at CMC has performed better for the removal of IBU and TCS than crude biosurfactants without any formation of toxic intermediates. Hence, this study proved to be an eco-friendly, cost-effective and sustainable treatment option for domestic wastewater treatment. © 2022 Elsevier LtdItem Green synthesis of mesoporous silica nanoparticles (MSNs) and its application on degradation of triclosan(Elsevier Ltd, 2024) Vamsi, E.B.; Devatha, C.P.The widespread use of triclosan (TCS) across the globe poses a substantial threat to both human well-being and the ecosystem. This necessitates the development of eco-friendly adsorption techniques to address triclosan contamination in wastewater. This research aims to develop novel eco-friendly synthesis method using Syzygium jambos (SJ) leaf extract to produce small-sized Mesoporous Silica Nanoparticles (MSNs) by varying surfactant to silica ratio. Different ratios such as 1:50, 1:100, and 1:200 (1 mL of tetraethyl orthosilicate (TEOS) is equivalent to cetyltrimethylammonium bromide (CTAB) in mg) were explored without chemical stabilising agents or alcohol diluents. The synthesized materials were named as MSN1, MSN2, and MSN3. Characterisation studies using Field emission scanning electron microscopy (FE-SEM) showed that MSN3 exhibited smallest size of 30 ± 5nm. The physical, chemical and morphological properties were analysed for the materials using X-Ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), Zeta potential (ZP), Brunauer-Emmett-Teller (BET), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). Notably, the developed nanomaterial demonstrated noteworthy stability with a ZP of ?33.1 mV and an impressive surface area of 545 m2/g. FT-IR peaks of biosorbent were obtained at 460, 800, and 975 1/cm. This confirms the existence of (Si–O–Si) bonds. The XRD results reveals that it possess amorphous nature of silica without any impurities. N2 adsorption-desorption studies yielded a pore radius of 16.8 Å and volume of pores are 0.890 cc/g indicating its potential as an adsorbent and its utility for material functionalisation. The developed biosorbent exhibited enhanced adsorption properties for removal of triclosan from synthetic wastewater with 76 % removal at 0.5g/L dose of adsorbent. © 2024 The AuthorsItem Investigation of diclofenac degradation by microbial biosurfactants from real-time wastewater(Taylor and Francis Ltd., 2025) Gnaneshwar, M.A.; Shanmathi, R.; Devatha, C.P.Microbial biosurfactants provide a sustainable solution by enhancing solubility and promoting the degradation of contaminants. The research explores the utilisation of waste cooking oil as a sustainable substrate for enhancing rhamnolipid biosurfactant production in Pseudomonas aeruginosa and its application on the removal of Diclofenac (DCF), a pharmaceutical contaminant from real-time wastewater. The optimised conditions led to a biomass yield of 6.7 g/L, critical micelle concentration (CMC) was determined to be 40 mg/L, and crude rhamnolipid production reached 7 g/L. The presence of glycosidic bonds was verified using Fourier transform infrared (FTIR) spectroscopy. At its CMC, the biosurfactants facilitated the complete removal of DCF within 48 hours. Toxicity analysis revealed that biosurfactants demonstrated lower phytotoxic effects, showcasing their biocompatibility. A comparative evaluation of treatment efficacy indicated that biosurfactants and chemical surfactants achieved complete DCF removal under UV-visible spectroscopy. Biosurfactant-induced degradation products with m/z values of 228 and 282 were identified using Liquid chromatography-mass spectrometry (LC-MS), indicating pathways involving de-chlorination and hydroxylation. The study implies the feasibility of biosurfactants as eco-friendly agents in removing pharmaceutical contaminants in wastewater, offering a sustainable approach towards environmental pollutants. © 2025 Indian Institute of Chemical Engineers.