Browsing by Author "Mangesh, V.L."

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Comparative risk assessment studies estimating the hazard posed by long-term consumption of PPCPs in river water /
(Elsevier, 2023-11-06) Mangesh, V.L.
This study assesses the risk due to Emerging Contaminants (ECs), present in Indian rivers – Ganga (650 million inhabitants), Yamuna (57 million inhabitants), and Musi (7,500,000 inhabitants), 13 ECs in total, have been used for risk assessment studies. Their concentrations (e.g., Fluconazole: 236950 μg/l, Ciprofloxacin: 31000 μg/l, Caffeine: 21.57 μg/l, etc.) were higher than the threshold concentrations for safe consumption (e.g. Fluconazole allowable level is 3.8 μg/l, and Ciprofloxacin allowable level is 0.51 μg/l). Three different pathways of emerging contaminants (ECs) transfer (oral water ingestion, oral fish ingestion, and dermal water contact) have been considered and the study is carried out in 2 ways: (i) deterministic and (ii) probabilistic approaches (using Monte Carlo iterative methods with 10000 simulations) with the aid of a software – Risk (version 7.5). The risk value, quantified by Hazard Quotient (HQ) is higher than the allowable limit of 1 for several compounds in the three rivers like Fluconazole (HQ = 18276.713), Ciprofloxacin (HQ = 278.675), Voriconazole (HQ = 14.578), Cetirizine (HQ = 1006.917), Moxifloxacin (HQ = 8.076), Caffeine (HQ = 55.150), and Ibuprofen (HQ = 9.503). Results show that Fluconazole and Caffeine pose the maximum risk in the rivers via the “oral pathway” that allows maximum transfer of the ECs present in the river (93% and 82% contribution to total risk). The risk values vary from nearly 25 times to 19000 times the United States Environmental Protection Agency (USEPA) threshold limit of 1 (e.g., Caffeine Infant Risk = 25.990 and Fluconazole Adult Risk = 18276.713). The most susceptible age group, from this study, is “Adults” (19–70 years old), who stand the chance of experiencing the adverse health hazards associated with prolonged over-exposure to the ECs present in the river waters. Musi has the maximum concentration of pollutants and requires immediate remediation measures. Further, both methods indicate that nearly 60–70% of the population in all the three study areas are at risk of developing health hazards associated with over-exposure to ECs regularly, making the areas inhabitable.
Correlation between the particle size, structural and photoluminescence spectra of nano NiCr2O4 and La doped NiCr2O4 materials
(Celpress, 2023-11-01) Mangesh, V.L.
Nano NiCr2O4 undoped and La doped NiCr2O4 nanorods array were successfully prepared by solution based conventional method[sbcm]. The synthesized samples were characterized by the diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy for finding optical properties. Further, the samples structure confirmed by Fourier transforms infrared (FTIR), and X-ray diffraction (XRD)techniques. High-resolution transmission electron microscopy (HRTEM) analysis revealed the attachment of NiCr2O4 nanorods on surface of nanoparticles. From the results, it was found that the reaction time, band gap energy, and particle size strongly influenced by changing the concentration of La in NiCr2O4. This work is notable for its examination of the impact of the precursor on the optical and structural characteristics of samples of La-doped and undoped NiCr2O4. This was the first time the investigation had been done. The average particle size of the La-doped and undoped NiCr2O4 samples is between 16 and 24 nm.
Fe-Ni bimetallic supported on mordenite catalyst for selective oxidation of veratryl alcohol in a continuous reactor /
(Elsevier, 2023-11-30) Mangesh, V.L.
Veratryl alcohol (VA) is preferentially oxidized to veratraldehyde (VADE) using a heterogeneous catalyst, which is more favoured in industries. Commercial mordenite (Ca,Na2,K2) Al2Si10O24·7H2O) was desilicated with NaOH and loaded with nickel and iron bimetal by the wet impregnation method. The synthesised Mordenite-Fe(5 %)/Ni(5–20 %) bimetallic catalyst, possessing active Bronsted acid sites, was employed to selectively oxidize the veratryl alcohol reaction. FT-IR, XRD, BET, HR-SEM, HR-TEM, and TPD were employed to determine the catalyst's textural attributes, morphology, chemical properties, and stability. Selective oxidation was performed over the catalysts using TBHP as an oxidant in a continuous reactor. To examine the most active catalyst among the four and to maximise the conversion and yield, the reaction conditions are optimised for various reaction parameters The reaction conditions were optimized by attaining 100 % conversion at temperature (90° C) for time (2 hr) and a maximum conversion of 97 % and a selectivity of 99 % at 10 bar pressure, WHSV (1.0 h−1) with acetonitrile solvent. The result of the study display that Fe (5 %) and Ni(15 %) impregnated on mordenite exhibits excellent catalytic stability with conversion (100 %) and selectivity (99 %) among the other catalysts. During regeneration, the conversion rate declined from 99.5 to 92.4.7 % and selectivity declined from 100 % to 96.2 % at the end of the seventh cycle. The high selectivity and stability of MOR-Fe(5 %)/Ni(15 %) imply that they might function properly as appropriate catalysts for the oxidation of aromatic alcohols. The advantages of the current synthesis are its cost-efficiency and eco-friendliness.
Green synthesis of silver nanoparticles using sustainable bio-fertilizer (Panchakavyam) for the selective oxidation of propylene glycol and veratryl alcohol /
(Elsevier, 2023-10-12) Mangesh, V.L.
This study demonstrates the selective oxidation of propylene glycol and veratryl alcohol utilizing silver oxide nanoparticles. This work adopted employing Panchakavyam, a medicinally rich bio-fertilizer for synthesizing silver oxide nanoparticles. In the present study, panchakavyam was prepared as a supporting material for the synthesis of silver oxide nanoparticles (Ag2O NPs). The traditional source of panchakavyam makes it cost effective, eco-friendly and the positive alteration of structure and shape of the catalyst enabled to deliver high yield of value added products. The synthesized silver oxide nanoparticle’s structure, shape, reactivity, stability, nature of the catalyst, thermal behaviour were studied and analysed through standard catalyst characterization techniques. Post synthesis of nanoparticles, selective oxidation reaction was carried out by confining the silver oxide nanoparticles as a nano catalyst. The tert-butyl hydroperoxide was chosen as the solvent for the oxidation studies of propylene glycol and veratryl alcohol. This study was performed by varying the reaction parameters such as temperature, pressure, time, WHSV−1 etc., to obtain the maximum yield of most desired product. The study involving conversion of propylene glycol(PG) to hydroxy acetone(HA) showed a conversion and selectivity of 100 and 99%, respectively. Similarly conversion of veratryl alcohol(VAOL) to veratraldehyde(VAL) showed a conversion and selectivity of 100 and 97.8%, respectively. The result of the study provides a path to explore the adoption of sustainable catalyst in the conversion of propylene glycol and veratryl alcohol to an industrially important products.