Faculty Publications
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Item Defluoridation of fresh water using the process of Electrocoagulation combined with Adsorption(2013) Wali, A.; Saidutta, M.B.In India, fluoride is the major inorganic pollutant of natural origin found in groundwater. Fluoride pollution occurs due to natural and manmade reasons and high concentrations have a detrimental effect on health. Electrochemical techniques like Electrocoagulation(EC) appears to be one of the most effective approaches for treatment of water and wastewater because of its versatility, safety, selectivity, amenability to automation and environmental compatibility. Results show that the percentage removal of fluoride was around 94 to 96% for monopolar and bipolar electrodes. Adsorbents like tricalcium phosphate and activated alumina used along with electrocoagulation process also gave promising results. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Receptor with an active methylene group as binding site for extraction of inorganic fluoride ions from seawater(Wiley-VCH Verlag info@wiley-vch.de, 2014) Kigga, M.; Trivedi, D.R.Two new receptors R1 and R2 based on triphenylphosphonium salts with an active methylene group as binding site have been designed and synthesised for the detection of F- ions. The detection limit of these receptors in organic media was found to be 0.2 ppm. Upon adding F- ions, a ??max of 188 nm and 256 nm was observed for receptors R1 and R2, respectively. The detection process followed deprotonation of the methylene proton, which has been confirmed by 1H NMR titration. The receptors were evaluated for real-life applicability by extracting F- ions from aqueous media and seawater into organic media. Receptor R2 was able to extract F- ions from seawater with 99 % efficiency. The level of F- ions present in seawater has been quantified and found to be 1.4 ppm, which is comparable to the reported literature value. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Colorimetric anion sensors based on positional effect of nitro group for recognition of biologically relevant anions in organic and aqueous medium, insight real-life application and DFT studies(Elsevier B.V., 2018) Singh, A.; Sahoo, S.K.; Trivedi, D.R.A new six colorimetric receptors A1-A6 were designed and synthesized, characterized by typical common spectroscopic techniques like FT-IR, UV–Visible, 1H NMR, 13C NMR and ESI-MS. The receptor A1 and A2 exhibit a significant naked-eye response towards F? and AcO? ions in DMSO. Due to presences of the NO2 group at para and ortho position with extended ?-conjugation of naphthyl group carrying –OH as a binding site. Compared to receptor A2, A1 is extremely capable of detecting F? and AcO? ions present in the form of sodium salts in an aqueous medium. This is owed to the occurrence of –NO2 group at para position induced in increasing the acidity of –OH proton. Consequently, it easily gets deprotonated in aqueous media. The detection limit of receptor A1 was turned out to be 0.40 and 0.35 ppm for F? and AcO? ions which is beneath WHO permission level (1.0 ppm). Receptor A1 shows a solitary property of solvatochromism in different aprotic solvents in presence of AcO? ion. Receptor A1 depicts high selectivity towards AcO? ion in DMSO: HEPES buffer (9:1, v/v). Receptor A1 proved itself for real life application by detecting anion in solution and solid state. The binding mechanism of receptor A1 with AcO? and F? ions was monitored from 1HNMR titration and DFT study. © 2017 Elsevier B.V.Item Studies on Toxicity of Fluoride and Impact of Endemic Fluorosis from Groundwater Resources of Bagalkot District, Karnataka – Geospatial Information System Approach(Geological Society of India, 2019) Gaonkar, S.M.; Karabasannavar, S.S.; Patil, V.B.B.; Kalashetty, M.B.; Kalshetty, B.M.Fluorine is most electronegative element, never occurs in free state due to its high reactivity. In most of the places of the world drinking water from underground sources is invariably contaminated with fluoride. The concentration of fluoride according to the WHO standard allowed upper limit is 1.5 ppm whereas as per Indian standard, the allowed upper limit is 1.0 mg/litre. Fluoride ion gets contaminated in drinking water due to weathering of the soil and rocks and the groundwater sources of granite belt of Bagalkot district, contain much higher concentration of fluoride (up to 6 or 7 ppm). In this survey it is found that the concentration of fluoride even at 1.34 ppm has caused tooth decay with the permanent brown scales on the teeth. © 2019, Geological Society of India.Item Design and synthesis new colorimetric receptors for naked-eye detection of biologically important fluoride and acetate anions in organic and arsenite in aqueous medium based on ICT mechanism: DFT study and test strip application(Elsevier B.V., 2020) Singh, A.; Mohan, M.; Trivedi, D.R.Novel three colorimetric anion receptors R1, R2 and R3 have been designed and synthesized via condensation reaction and characterized using IR, MS, and NMR spectroscopic techniques. Anion sensing properties were studied using colorimetric, UV–vis titration, 1H NMR titration, and Cyclic Voltammetric Studies. Comparing the UV–visible titration data of the receptors R1 and R2, R2 showed high redshift (??max) in the mixed competitive solution (DMSO: H2O, 9: 1; v/v) of about 155 nm, 157 nm, 169 nm for Na+F?, Na+AcO?, and Na+AsO2 ? ions with LOD of 0.23 ppm, 0.18 ppm, and 0.30 ppm, respectively. The observed spectral change of receptor R2 is due to the anion-induced deprotonation of the OH proton, which is confirmed by UV–vis titration, 1HNMR titration, and cyclic voltammetric studies. Theoretical studies via DFT calculation were carried for R1 and R2 to optimize the structure and to explain the anion-binding mechanism. The application of designed receptor R2 was successfully demonstrated for the detection of F? and AsO2 ? ions using a test strip. The receptors R1 and R2 proved itself to be potentially useful for real-life application by sensing F? and AcO? ions in real samples like toothpaste, mouthwash, vinegar and seawater in a complete aqueous medium. © 2019 Elsevier B.V.Item Design and synthesis of malonohydrazide based colorimetric receptors for discrimination of maleate over fumarate and detection of F?, AcO? and AsO2 ? ions(Elsevier B.V., 2020) Singh, A.; Mohan, M.; Trivedi, D.R.In this study, we have designed and synthesized two new organic receptors R1 and R2 based on malonohydrazide for the recognition of biologically important anions. The receptor R1 capable of colorimetric discrimination of maleate over fumarate ion, exhibit significant color change from pale yellow to wine red due to intermolecular hydrogen bond between the R1 and maleate ion, supported by 1HNMR titration, where the peak at ?12.0 ppm attributed to the NH proton experiences a downfield shift upon binding with maleate ion. Receptor R1, equipped with two electron-withdrawing [sbnd]NO2 moieties as the chromogenic signaling unit enhance the hydrogen bonding tendency and acidity, and thus when comparing with receptor R2, R1 displayed substantial higher redshift (??max) of 148 nm, 143 nm, and 140 nm towards F?, AcO?, and maleate anion in the DMSO. In addition, the synthesized receptors R1 and R2 are able to detect F?, AcO?, and AsO2 ? ions as their sodium salts in an aqueous solution with visual color change. Receptor R1 exhibit electrochemical response towards F? and AcO? ions. The receptors R1 and R2 are successfully applied for quantitative detection of F? ion in the toothpaste solution in an aqueous medium. Additionally, R1 and R2 exhibit fluorescence enhancement towards F? and AcO? ions in the DMSO. As well, R1 and R2 demonstrate to be potentially useful colorimetric chemosensor for sensing maleate ion using the test strip. The theoretical calculation based on TD-DFT corroborates well with the experimental results of the receptors R1 and R2 with fluoride, acetate and maleate. © 2019 Elsevier B.V.Item Groundwater hydrochemistry of Rajnandgaon district, Chhattisgarh, Central India(Elsevier B.V., 2020) Ankit, A.; Nanda, A.; Sahu, B.L.; Sahu, Y.K.; Patel, K.S.; Pervez, S.; Gulgundi, M.S.; Cuchí-Oterino, J.A.; Martín-Ramos, P.; Bhattacharya, P.The spreading of fluorosis diseases in Central India related to high concentrations of fluoride ion (F?) is a cause of major concern. In this work, the hydrochemistry of the aquifers related to Seonath River, in Rajnandgaon district, Chhattisgarh state, India, has been studied, focusing on the presence and sources of F?. Hydrochemical parameters were analyzed in the post-monsoon season in 160 wells located in nine tehsils, finding F? concentrations ranging from 0.6 to 18.5 mg L?1. Seasonal variations were also studied in Chhuikhadan tehsil, in which the highest F? values were registered, finding a noticeable enrichment in the pre-monsoon months. In many locations of the district, F? concentrations exceeded the recommended value of 1.5 mg L?1, which have led to the appearance of several health issues. Multidimensional analysis statistical methods were adopted to investigate the sources of F?, and the mineralization of bedrock elements into the groundwater was observed to be the primary source. © 2020 Elsevier B.V.Item Chromogenic detection of fluoride, dihydrogen phosphate, and arsenite anions based on 2,4-dinitrophenyl hydrazine receptors: spectral and electrochemical study(Taylor and Francis Ltd., 2021) K, N.; Singh, A.; Nityananda Shetty, A.N.; Trivedi, D.R.The colorimetric recognition of biologically relevant fluoride (F?), acetate (AcO?), and dihydrogen phosphate (H2PO4?) ions, and poisonous arsenite (AsO2?) ions, was devised and new receptors for these anions synthesised via the Schiff base condensation procedure. UV–visible titration, fluorescence titration, 1H-NMR titration, and cyclic voltammetry were used to explore the interactions of receptors R1–R3 with anions and possible detection mechanisms. The synthesised probes could sense inorganic fluoride, acetate, dihydrogen phosphate, and arsenite in the organo–aqueous medium (H2O/ Dimethylsulphoxide, 1:?9, v/v) and displayed a change in colour detectable to the naked eye. Out of the three synthesised receptors, receptor R1 showed better sensing ability of fluoride, acetate, dihydrogen phosphate, and arsenite ions in the organo–aqueous medium with a lower detection limit of 0.1 ppm, 0.171 ppm, 0.194 ppm, and 0.144 ppm, respectively. All three receptors formed complexes with the anions through H-bonding interaction followed by deprotonation of the NH proton. © 2022 Informa UK Limited, trading as Taylor & Francis Group.Item Effect of nano-hydroxyapatite incorporation on fluoride-releasing ability, penetration, and adaptation of a pit and fissure sealant(John Wiley and Sons Inc, 2022) Netalkar, P.P.; Maithreye, S.R.; Karuna, Y.M.; Srikant, S.; Gadipelly, T.; Bhat Panemangalore, B.P.; Dasgupta, A.; Lewis, A.Background: Dental caries is one of the most common multifactorial oral diseases and can be prevented using pit and fissure sealants. Aim: To evaluate the effect of nano-hydroxyapatite (nanoHAP) incorporation on fluoride-releasing ability, penetration, and adaptation of a pit and fissure sealant. Design: This was an in vitro study with two groups: conventional sealant and nanoHAP-incorporated sealant. Sealant penetration and adaptation were assessed using stereomicroscope and scanning electron microscope (SEM) (15 and 10 samples per group, respectively). Fluoride release was analyzed using ion-selective electrode (15 samples per group). The chi-square test was used to compare penetration and adaptation between the 2 groups, and an independent Student t test was used to compare fluoride release. Results: The nanoHAP group showed significantly more samples with no bubbles (P =.001) and no debris (P <.001). SEM analysis showed a significantly greater percentage of adequate fissures in the test group (P =.007). The fluoride release was significantly higher in test samples with p values of.001 and.016 on day 1 and day 60, respectively. Conclusion: The incorporation of nanoHAP into the conventional pit and fissure sealant improved its penetration and adaptation properties along with fluoride release. © 2021 BSPD, IAPD and John Wiley & Sons Ltd.