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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    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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    Removal of toxic arsenic from aqueous media using polyphenylsulfone/cellulose acetate hollow fiber membranes containing zirconium oxide
    (Elsevier B.V., 2020) Kumar, M.; Isloor, A.M.; Somasekhara Rao, T.; A.F., A.F.; Farnood, R.; Nambissan, P.M.G.
    Arsenic is one of the highly dangerous metalloid present in the polluted water, it's effective and economical removal is one of the major challenges to the researchers. It was planned to prepare hollow fiber membranes using polyphenylsulfone (PPSU) as a polymer, cellulose acetate (CA) and cellulose acetate phthalate (CAP) as additives with increased dosages (0.6, 1 and 1.5 wt%) of zirconium oxide (ZrO2) nanoparticle. The fabricated hollow fiber membranes were characterized by SEM, AFM, zeta potential, ATR-FTIR and XPS to analyze the membrane's morphologies (cross-section and surface), topography, surface charge and assessment of different functional groups. As used ZrO2 was characterized by TEM and XRD to analyze the morphology and crystallinity. The positron annihilation lifetime spectroscopy (PALS) analysis was carried out for neat and ZrO2 contained membranes, to study the expansion of free-volume in membrane morphology. Leaching studies of the used zirconium with respect to different pH from the ZrO2 contained hollow fiber membrane was also examined. The enhancement of membrane hydrophilicity was confirmed by contact angle, porosity, water uptake and pure water permeability measurements. Membranes prepared by 1 wt% of ZrO2 in PPSU/CA (PZCA-1) and 0.6 wt% of ZrO2 in PPSU/CAP (PZCAP-0.6) were proved to be efficient as arsenic removal membranes (i.e. PZCA-1 as 87.24% and PZCAP-0.6 as 70.48% and permeability of 89.94 L/m2h bar and 70.59 L/m2h bar respectively) using lab-prepared 1 ppm standard arsenic solution at pH range of 6.8 ± 0.2. Also, there is a decrease in the arsenic removal tendency was observed with the excessive dosages of ZrO2, which is due to the concentration polarization on surfaces of the membranes. Antifouling behavior of the prepared hollow fiber membranes was also studied using bovine serum albumin (BSA). © 2020
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    Effect of binary zinc-magnesium oxides on polyphenylsulfone/cellulose acetate derivatives hollow fiber membranes for the decontamination of arsenic from drinking water
    (Elsevier B.V., 2021) Kumar, M.; Isloor, A.M.; Todeti, S.R.; Nagaraja, H.S.; A.F., A.F.; Susanti, R.
    Arsenic contamination is continuously threatening the safety of drinking water in many parts of the world. The consumption of chronic arsenic contaminated drinking water can cause serious health related issues. Therefore, the synthesis of novel materials is very much essential for the selective removal of arsenic from aqueous solution. In the present investigation, the effect of increased concentrations (0.6, 1.0 and 1.5 wt%) of binary zinc-magnesium oxide (ZnO-MgO) on cellulose acetate (CA)/polyphenylsulfone (PPSU) and cellulose acetate phthalate (CAP)/PPSU hollow fiber membranes for arsenic removal was performed. As used ZnO-MgO was characterized by using x-ray diffraction (XRD), transmission electron microscopy (TEM) and particle size distribution. Fabricated hollow fiber membranes were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, fourier transform infrared (FTIR), x-ray photoelectron spectrophotometer (XPS), thermogravimetric analysis (TGA) and antifouling studies. The results revealed that, there is significant enhancement in the overall performance of the ZnO-MgO containedmembranes. An enhancement of arsenic removal properties was demonstrated from 0.6 wt% of ZnO-MgO in CAP/PPSU (ZMCAP-0.6) membrane was 81.31% with the retention permeability of 69.58 L/m2h bar respectively. Similarly, 1 wt% of ZnO-MgO in CA/PPSU (ZMCA-1) was found to be 78.48% and 198.47 L/m2h bar respectively using 1 ppm laboratory prepared aqueous arsenic solution (pH 6.8 ± 0.2) at 1 bar transmembrane pressure. In addition, improved antifouling properties was noticed with an increased flux recovery ratio and enhanced thermal stability from ZnO-MgO contained membranes. Therefore, as fabricated ZnO-MgO contained membranes provided enhanced arsenic removal tendency without compromising the retention permeability. © 2020
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    Effect of Bioprecipitation and Ferrochrome Ash Stabilization on the Strength of Black Cotton Soil
    (Springer Science and Business Media Deutschland GmbH, 2023) Kothuri, M.; Devatha, C.P.
    This study aims to stabilize black cotton soil in an environmentally friendly manner by integrating chemical stabilization and bioprecipitation. To improve the unconfined compressive strength (UCS), the soil was partially replaced by ferrochrome ash (FCA) and blended with urease positive bacteria, urea, and calcium chloride. Characterization studies examined microstructural changes. Leachate analysis determined whether this method is environmentally safe. Consequently, experiments were conducted using a central composite design and the UCS was modeled using response surface methodology (RSM) to evaluate the influence of each additive. Liquid extracts of stabilized soil were analyzed for concentrations of chromium, iron, zinc, lead, nickel, cadmium, copper, titanium, mercury, and arsenic. An improvement in the UCS from 35 kPa to 350 kPa was noticed when 40% of the soil was replaced with FCA and mixed with a bacterial solution of optical density 1.12, containing 0.5 g calcium chloride and 0.5 g urea. FCA content, the optical density of the bacteria, and the urea concentration were the factors affecting the UCS significantly. Lead, cadmium, titanium, mercury, and arsenic were not detected in water-based extracts of stabilized soil due to the immobilization effect of calcite. X-ray diffraction (XRD), Field emission gun scanning electron microscopy (FEGSEM), Fourier transform infrared spectroscopy (FTIR), and Thermogravimetric (TG) analyses supported the formation of calcite due to bioprecipitation. Based on the results, it is concluded that FCA and bioprecipitation complement each other to overcome their limitations and successfully enhanced the strength of black cotton soil in an environmentally conscious manner. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    Colorimetric recognition of water-polluting inorganic arsenic anions using near-infrared chemosensors in organic and semi-aqueous medium
    (Springer Science and Business Media Deutschland GmbH, 2023) K, K.; Nityananda Shetty, A.N.; Trivedi, D.R.
    Highly sensitive and selective chemosensors N2R1–N2R3 for detecting water-polluting inorganic arsenic anions, arsenite, and arsenate were synthesized and characterized. The selectivity of anions was studied in the pure organic media as well as the organo-aqueous media. Receptors N2R1 and N2R3 exhibited selectivity toward arsenite ion over arsenate ion in the acetonitrile media with a Limit of Detection (LOD) of 0.119 ppm and 0.323 ppm, respectively. In 30% aq. DMSO, receptors N2R1–N2R3 displayed selectivity toward arsenite and arsenate with a better LOD of 0.044 ppm. The anion binding to the receptor achieved a spectral absorption shift toward the near-infrared region in both organic and aqueous media, making the receptors better colorimetric sensors. The cyclic voltammetric investigations, 1H–NMR titration, UV–Vis titration, and DFT experiments provided strong evidence for the initial H-bonding upon interaction with the anions and the subsequent deprotonation pathway for the detection of inorganic arsenic anions. © 2023, King Abdulaziz City for Science and Technology.
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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.