Faculty Publications
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Item Synthesis and application of Zr-metal–organic framework for simultaneous detection and rapid adsorption of p-nitrophenol from water(Institute for Ionics, 2023) Nimbalkar, M.N.; Badekai Ramachandra, B.R.The p-nitrophenol is a prime raw material in the manufacturing of pharmaceutical drugs, fungicides and insecticides. The effluents from these industries contain p-nitrophenol and are harmful to human and aquatic life. Hence, development of fast detection and efficient disposal process of p-nitrophenol in wastewater is a major concern. In this study, fluorescent active smart metal–organic framework (MOF) was employed for the simultaneous detection and adsorptive removal of p-nitrophenol from water. Photoluminescence active zirconium-based metal–organic framework having isostructural with UiO-66 framework was synthesized by using mixed ligand strategy with the replacement of BDC (1,4-Benzenedicarboxylic acid) ligand from 10 to 30 mol% with H3ntb ligand (4,4ʼ,4ʼʼ-Nitrilotrisbenzoic acid, in house synthesised fluorescence active trifunctional ligand). The powder X-ray diffraction (PXRD), analysis of the synthesised MOF confirms face centred cubic (FCC) crystal structure similar to pristine UiO-66. From Fourier transform infrared spectroscopy (FTIR), the peak at 1251 cm−1 for the tertiary amine group validated the presence of H3ntb ligand. The obtained MOFs have the surface area from 1039 m2g−1 to 949.1 m2g−1 and pore volume ranging from 0.04973 cm3g−1 to 0.05160 cm3g−1. Experimental results indicated that MOF was able to detect p-nitrophenol at low concentration (≈35 μM) and to remove rapidly (< 10 min) it from the aqueous solution. The adsorption process obeys Langmuir isotherm (monolayer adsorption capacity is 62 mgg−1) and kinetics by Elovich model indicating adsorption nature as chemisorption on a heterogeneous surface. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Enhancing supercapacitor performance with zinc doped MnSe nanomaterial(Springer, 2024) Mascarenhas, F.J.; Badekai Ramachandra, B.R.The decreasing availability of fossil fuels and the increasing demand for energy highlight the pressing need for sustainable energy sources. Electrochemical technologies, notably supercapacitors, play a key role. They promise renewable energy storage, necessitating high-performing, safe, and affordable electrode materials. In this study, we present a novel hydrothermal synthesis method for producing MnSe and ZnxMn1-xSe materials across a range of concentrations (x = 0.01, 0.02, and 0.03). Characterization techniques including XRD, FESEM, HRTEM, BET and Raman analysis were employed. Among the synthesized compositions, Zn0.03Mn0.97Se emerged as the most promising material for supercapacitor applications. Evaluation through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) revealed specific capacitance values of 135 F/g at 3 mV/s and 95 F/g at 0.5 A/g for Zn0.03Mn0.97Se. Furthermore, the material demonstrated impressive stability, retaining 97% of its capacitance after 1000 cycles. Additionally, to validate the potential of the synthesized electrode, we assembled a two-electrode symmetric cell using Zn0.03Mn0.97Se as both positive and negative electrode material in a 5 M KOH electrolyte. Extensive characterization techniques, including CV, GCD, and long-term cyclic stability tests, revealed compelling evidence of the material’s robust electrochemical behavior. These findings underscore the potential of Zn0.03Mn0.97Se for supercapacitors, contributing to the advancement of sustainable energy storage. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Item Electrochemical insights into manganese-cobalt doped ?-Fe2O3 nanomaterial for cholesterol detection: a comparative approach(Royal Society of Chemistry, 2025) Sushmitha, S.; Ray, S.; Rao, L.; Nayak, M.P.; Carva, K.; Badekai Ramachandra, B.R.Herein, a self-assembled hierarchical structure of hematite (?-Fe2O3) was synthesized via a one-pot hydrothermal method. Subsequently, the nanomaterial was doped to obtain MxFe2?xO3 (M = Mn-Co; x = 0.01, 0.05, and 0.1) at precise concentrations. An electrode was fabricated by coating the resulting nanocomposite onto a nickel foam (NF) substrate. Electrochemical characterization demonstrated the excellent performance of cobalt-doped ?-Fe2O3, among which Co0.05Fe0.95O3 (CF5) exhibited a superior performance, showing a two-fold increase in sensitivity of 1364.2 ?A mM?1 cm?2 (±0.03, n = 3) in 0.5 M KOH, a limit of detection (LOD) of ?0.17 mM, and a limit of quantification (LOQ) of ?0.58 mM. The Density Functional Theory (DFT) was performed to understand the doping prompting in the reduced bandgap. The fabricated electrode displayed a rapid response time of 2 s and demonstrated 95% stability, excellent reproducibility, and selectivity, as confirmed by tests with several interfering species. A comprehensive evaluation of the electrode's performance using human blood serum highlighted its robustness and reliability for cholesterol detection in clinical settings, making it a promising tool for clinical and pharmaceutical applications. © 2025 The Royal Society of Chemistry.Item Silver-doped zirconium copper oxide nanohybrid for electrochemical identification of dihydroxybenzene isomers(Springer Science and Business Media Deutschland GmbH, 2025) Achar, S.; Bhat, R.S.; Sajankila, S.P.; Badekai Ramachandra, B.R.The transition metal oxide (TMO) nanohybrids are the optimal electrode materials for the electrochemical recognition of the dihydroxybenzene isomers (DHBIs). The DHBIs includes mainly catechol (CA), hydroquinone (HY), and resorcinol (RE). In the current study, Ag-ZrCuO nanohybrid is synthesized by the efficient combustion method. The crystal structure of the synthesized nanohybrid is analyzed using X-ray diffraction (XRD) analysis. The morphological features and elemental compositions are investigated through field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) analysis. The presence of different vibrational modes is studied by Raman spectroscopy. As synthesized Ag-ZrCuO nanohybrid is deposited on the glassy carbon electrode (GCE) and electropolymerized with L-valine, resulting in poly-valine-reduced graphene oxide-silver doped zirconium oxide/copper oxide nanohybrid-GCE (PV-rGO-Ag-ZrCuO-GCE). The fabricated electrode exhibits superior electrochemical redox activity compared to the bare GCE, as confirmed by electrochemical impedance spectroscopy (EIS) and Tafel plots. The modified electrode is implemented for the electrochemical recognition of DHBIs by employing linear sweep voltammetry (LSV), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) techniques. The PV-rGO-Ag-ZrCuO-GCE detects CA, HY, and RE, with a limit of detection (LOD) determined to be 0.026 µM, 0.005 µM, and 0.082 µM. The corresponding linear ranges were 0.2–3.4 µM, 0.3–5.5 µM, and 0.2–1.4 µM. In addition, the prepared electrode shows excellent response for commercially available samples and the ternary mixture of DHBIs. The fabricated electrode displays a high percentage of repeatability, reproducibility, stability, and selectivity for the electrochemical detection of DHBIs. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.