Faculty Publications

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    Biologically synthesized PbS nanoparticles for the detection of arsenic in water
    (Elsevier Ltd, 2017) Uddandarao, U.; Gowda K M, A.; M G, E.; Teja B, S.; Nitish, N.; Mohan B, R.
    Semiconductor nanoparticles have gained importance because of their interesting optical properties. Among these, lead sulfide (PbS) has been extensively studied due to its potential technological applications in field effect transistors, solar cells, photo-voltaics, light emitting diodes, photocatalysis, photo-luminescence, infrared photodetectors, environmental and biological sensors. Hence there is a need to explore cost effective and eco-friendly biological routes for their synthesis. In this paper, biosynthesis of PbS nanoparticles were carried out using endophytic fungi, subsequently detailed characterization was also performed using UV–visible, fluorescence spectrometer, FTIR, SEM, TEM, EDX and XRD. TEM revealed the formation of PbS nanoparticles in typical size range of 35–100 nm. The application of these nanoparticles for detection of arsenic in aqueous solution through their absorbance properties was also dealt. Importantly, the results were demonstrated for detection of 50 ppb As (III) in water without any interference of other selected ions maintained upto 20 ppb under same conditions. Further, the correlation for the bio-sensitivity of PbS nanoparticles based on the quenching effect with arsenic concentrations ranging between 10 and 100 ppb in water samples was deduced. © 2016 Elsevier Ltd
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    Nano-scale Iron Oxide as Heterogeneous Fenton Catalyst for Organic Pollution Degradation and Heavy Metal Remediation in Water Sample of Byramangala Lake, Karnataka
    (IOS Press Nieuwe Hemweg 6B Amsterdam 1013 BG, 2019) Nagappa, D.; Manu, B.
    A nano-scale iron oxide (Fe2O3/Fe3O4) heterogeneous Fenton catalyst was synthesized for aqueous heavy metals remediation and was utilized to degrade organochlorine pesticides (OCPs), namely, alpha-, and delta-hexachlorocyclohexane (?-HCH and ?-HCH) as well as heptachlor epoxide (HE), in Byramangala lake water sample. Nano-scale Fe2O3/Fe3O4 was synthesized via Solution Combustion Synthesis (SCS), with glycine as fuel and iron oxide separated from raw laterite soil sample (RL) as oxidizer for the reaction. Based on detailed characterization, it was found that iron oxide constituted 34.31% of the RL sample. Later, detection of hematite (Fe2O3), hypersthenes (MgSiO4) and lepidocrocite (FeOOH) in the separated fraction confirmed extraction of Fe2O3 fraction. Next, collection of Byramangala lake water samples and analyses of physico-chemical parameters revealed nil dissolved oxygen (DO) and high chemical oxygen demand (COD) levels. Oxidation of detected pesticides and susceptible heavy metals using the nano-scale Fe2O3/Fe3O4 was investigated under various experimental conditions: pH (3 and 7), dosages of H2O2 (1-9 mM L-1) and nano catalyst (0.05-0.4 g L-1), as well as contact time (5-120 min) in batch experiments. Optimum values were found to be contact time of 50 mins at near-neutral pH at 5 mM L-1 H2O2 and 0.25g L-1 Fe2O3/Fe3O4 dosages, respectively. Under optimized conditions, 100% removal of both ?-HCH and ?-HCH, and 99% removal of HE were observed. Furthermore, appreciable reduction in arsenic (As) and manganese (Mn) concentrations (95% and 76.6%) was also observed. Post-treatment, Fe2O3/Fe3O4 could be efficiently separated by an external magnetic field because of its ferromagnetic behaviour. © 2019 - IOS Press and the authors. All rights reserved.
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    Use of cellulose acetate/polyphenylsulfone derivatives to fabricate ultrafiltration hollow fiber membranes for the removal of arsenic from drinking water
    (Elsevier B.V., 2019) Kumar, M.; Todeti, S.; Isloor, A.M.; Gnani Peer Mohamed, G.P.S.; Siddique, I.; Ismail, N.I.; A.F., A.F.; Asiri, A.M.
    Cellulose acetate (CA) and cellulose acetate phthalate (CAP) were used as additives (1 wt%, 3 wt%, and 5 wt%) to prepare polyphenylsulfone (PPSU) hollow fiber membranes. Prepared hollow fiber membranes were characterized by surface morphology using scanning electron microscopy (SEM), surface roughness by atomic force microscopy (AFM), the surface charge of the membrane was analyzed by zeta potential measurement, hydrophilicity by contact angle measurement and the functional groups by fourier transform infrared spectroscopy (FTIR). Fouling resistant nature of the prepared hollow fiber membranes was evaluated by bovine serum albumin (BSA) and molecular weight cutoff was investigated using polyethylene glycol (PEG). By total organic carbon (TOC), the percentage rejection of PEG was found to be 14,489 Da. It was found that the hollow fiber membrane prepared by the addition of 5 wt% of CAP in PPSU confirmed increased arsenic removal from water as compared to hollow fiber membrane prepared by 5 wt% of CA in PPSU. The removal percentages of arsenic with CA-5 and CAP-5 hollow fiber membrane was 34% and 41% with arsenic removal permeability was 44.42 L/m2h bar and 40.11 L/m2h bar respectively. The increased pure water permeability for CA-5 and CAP-5 hollow fiber membrane was 61.47 L/m2h bar and 69.60 L/m2 h bar, respectively. © 2019 Elsevier B.V.
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    Adsorptive removal of trivalent and pentavalent arsenic from aqueous solutions using iron and copper impregnated melanin extracted from the marine bacterium Pseudomonas stutzeri
    (Elsevier Ltd, 2020) Manirethan, V.; Raval, K.; Mohan Balakrishnan, R.M.
    The metalloid arsenic is one of the most conspicuous groundwater contaminants in the Indian subcontinent and its removal from aqueous medium is the main focus of this study. The study aims at functionalising melanin using iron and copper for the efficient removal of arsenic and rendering water fit for consumption. Melanin obtained from the marine bacteria Pseudomonas stutzeri was functionalised by iron impregnation (Fe-melanin) and copper impregnation (Cu-melanin). Morphological studies using FESEM portrayed the impregnated iron and copper granules on the surface of melanin, while XRD analysis confirmed the presence of Fe2O3 and CuO on melanin. Adsorption studies on As (V) and As (III) were conducted using Fe-melanin and Cu-melanin for different operating variables like pH, temperature and contact time. More than 99% per cent of As (III) and As (V) from water was removed at a pH range between 4 and 6 within 50 min in the case of Fe-melanin and 80 min for Cu-melanin. Adsorption equilibrium studies showed better fit with Langmuir adsorption isotherm and had good agreement with Redlich-Peterson's three-parameter model. The maximum adsorption capacities of Fe-melanin and Cu-melanin obtained from Langmuir adsorption model are 50.12 and 20.39 mg/g, respectively, for As (V) and similarly 39.98 and 19.52 mg/g, respectively, for As (III). Arsenic-binding to the functionalised melanin was confirmed using FT-IR and the XPS analysis. Reuse of the adsorbent was effectively done by desorbing the iron and copper together with the bound As (III) and As (V) and further re-impregnation of iron and copper in melanin. Re-functionalised melanin showed 99% adsorption efficiency up to four cycles of adsorption/desorption. A novel iron and copper impregnated melanin was synthesized to remove As (III) and As (V) from groundwater and the adsorption process was optimized. © 2019 Elsevier Ltd
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    Assessment of Arsenic, Vanadium, Mercury, and Cadmium  in Food and Drug Packaging
    (F1000 Research Ltd, 2024) Mukhi, S.; Rukmini, M.S.; Manjrekar, P.; Iyyaswami, R.; Sindhu, H.
    Background: Food and drug packaging materials are an integral part of our everyday life.  Noxious elements can inadvertently be included in packaging materials in various stages of their production. Adulterants, adhesives, colorants and heavy metal interference are the common sources of contamination in food packaging materials. Heavy metal toxicity has far-reaching ill effects on living organisms. The present study aimed at qualitatively and quantitatively analysing heavy metal content of various materials that are used for food and drug packaging in India. Methods: The qualitative detection was done by rapid assay and heavy metals were quantified with the help of inductively coupled plasma-optical emission spectrometry (ICP-OES). A total of thirteen types of food and drug packaging materials were procured from local market and analysed for four heavy metals viz. arsenic (As), vanadium (V), mercury (Hg) and cadmium (Cd). The concentration of each heavy metal in the samples was compared with the permissible values published by the European Council. Results: Heavy metals were qualitatively detected in ten out of thirteen samples. Among the ten samples mercury and arsenic were detected the most followed by cadmium and vanadium. Quantitative estimation by ICP-OES showed presence of vanadium and cadmium in ten samples and arsenic and mercury in all the thirteen samples above the permissible range. Conclusions: The notable elevation in mercury concentration, followed by cadmium, arsenic and vanadium registering the least, presents a potential health hazard to consumers and compromises the food quality. ©: © 2024 Mukhi S et al.