Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
4 results
Search Results
Item Effective inhibition of mild steel corrosion by 6-bromo-(2,4-dimethoxyphenyl)methylidene]imidazo [1,2-a]pyridine-2-carbohydrazide in 0.5 M HCl: Insights from experimental and computational study(Elsevier B.V., 2021) Vranda Shenoy, K.; Venugopal, P.P.; Reena Kumari, P.D.; Chakraborty, D.A new inhibitor, 6-bromo-(2,4-dimethoxyphenyl)methylidene]imidazo [1,2-a]pyridine-2-carbohydrazide (DMPIP) was evaluated as a corrosion inhibitor for Mild Steel (MS) in 0.5 M HCl solution at 303–323 K using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) techniques. Both the techniques confirmed an increase in inhibition efficiency with the concentration of DMPIP but decrease with temperature. The highest inhibitive action (96.7%) was registered at 303 K for 500 ppm of DMPIP concentration. Polarization study revealed mixed inhibition action by DMPIP. Nyquist plot obtained for MS using EIS technique showed two capacitive loops on addition of inhibitor to HCl solution confirmed the inhibitory action of DMPIP via adsorption at the metal/solution interface. The surface morphology analysis was carried out by SEM, EDX and FTIR techniques. The adsorption process was demonstrated using Langmuir's adsorption isotherm model. The thermodynamic parameters (?Goads, ?Hoads) indicated that the adsorption was spontaneous and done by physisorption. Further, quantum chemical studies using Density Functional Theory (DFT) elucidated that the formation of Fe-DMPIP complex presumably due to the interaction of protonated form of DMPIP with the empty d orbitals of the iron atom. © 2021 Elsevier B.V.Item Exploring the potential role of quercetin in corrosion inhibition of aluminium alloy 6063 in hydrochloric acid solution by experimental and theoretical studies(Taylor and Francis Ltd., 2022) Kumari, D.; Venugopal, P.P.; Reena Kumari, P.D.; Chakraborty, D.Quercetin was evaluated as corrosion inhibitor for AA6063 in 0.5 M HCl solution by employing weight-loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), Atomic Force Microscopy (AFM), X-Ray photoelectron spectroscopy (XPS) techniques allied to quantum chemical studies. Electrochemical results substantiate that the inhibition efficacy of quercetin increases proportionally with the concentration of the inhibitor. The effect of temperature on the corrosion behavior of the alloy was studied in the range of 30–60 °C. Potentiodynamic polarization study confirms the mixed type of inhibition by quercetin with preferential control of the cathodic reaction. The adsorption of quercetin on alloy surface was explained through the Langmuir adsorption isotherm model. ΔG°ads values and its variation with the temperature ensured spontaneous adsorption through chemisorption and the process was endothermic. Further, quantum chemical parameters calculated from Density Functional Theory (DFT) method for quercetin, proved a perfect correlation between structure and corrosion inhibition efficiency. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Item Anti-corrosion investigation of a new nitro veratraldehyde substituted imidazopyridine derivative Schiff base on mild steel surface in hydrochloric acid medium: Experimental, computational, surface morphological analysis(Elsevier Ltd, 2022) Shenoy K, V.; Venugopal, P.P.; Reena Kumari, P.D.; Chakraborty, D.Intensive research has recently been directed toward synthesizing novel, non-toxic, and cost-effective organic inhibitors against metallic corrosion. In the present investigation, a non-toxic, novel Schiff base inhibitor, 6-bromo-(4,5-dimethoxy-2-nitrophenyl) methylidene] imidazo[1,2-a] pyridine-2-carbohydrazide (NVAIP) was synthesized and tested for its corrosion inhibition performance on Mild Steel (MS) in 1 M HCl at 303–323 K using potentiodynamic polarization study, electrochemical impedance spectroscopy (EIS) measurements, Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM) and X-Ray Photoelectron Spectroscopy (XPS) analyses. The electrochemical results stated the inhibition effectiveness (ƞ%) of NVAIP was dependent on concentration and temperature, with the maximum efficiency (92.3%) recorded at 303 K for 500 ppm. The mixed-type inhibitory effect of NVAIP was substantiated by the polarization test results. The Langmuir adsorption isotherm model accorded with the metal surface evaluated, and Gibbs free energy of adsorption values ranged from - 35.05 to-36.05 kJ/mol, implying a physical and chemical adsorption mechanism. Surface morphological analysis was carried out to characterize the chemical composition of the adsorbed inhibitor on the MS surface, and these techniques confirmed that the inhibitive layer is composed of an iron oxide/hydroxide mixture where NVAIP molecules are incorporated. Further, the physicochemical and electronic properties of the NVAIP were investigated using Density Functional Theory (DFT) and electrostatic potential energy mapping (ESP). ΔEads value of −57.21 kcal/mol obtained from Molecular Dynamic (MD) simulations correlates well with the experimental results. Moreover, the relevance of the molecular structure of NVAIP and its inhibition act was validated by quantum chemical calculations and molecular dynamic (MD) simulation studies. A possible inhibition mechanism was proposed based on the experimental, theoretical, and surface analysis results. The outcomes of all the techniques show consistent agreement with each other. © 2022 Elsevier B.V.Item A chemically robust amine-grafted Zn(ii)-based smart supramolecular gel as a regenerative platform for trace discrimination of nitro-antibiotics and assorted environmental toxins(Royal Society of Chemistry, 2023) Saha, E.; Chhetri, A.; Venugopal, P.P.; Chakraborty, D.; Mitra, J.Smart supramolecular metallogels are fascinating reusable materials with the potential for a wide range of sustainable applications including the detection of multiple lethal pollutants. We have assembled a chemically robust triazole-containing Zn(ii)-supramolecular gel (ZnGel), where the channels and surface of the gel are strategically decorated with triazole N and appended -NH2 units that are pivotal to ZnGel's efficacy as a multi-sensory probe. ZnGel shows selective fluorescence quenching in the presence of traces of nitro-antibiotics (LOD of nitrofurantoin: 4.62 ppm) and electron-deficient nitrophenols (LOD of 4-nitrophenol: 4.18 ppm), without any prior activation. Density functional theory calculations delineate the importance of the triazole gelator in the turn-off fluorescence response of ZnGel to divergent organo-toxins and substantiate the supramolecular interactions between the ZnGel and the analytes. Significant fluorescence quenching of ZnGel ensued in the presence of a trace amount of Fe3+ (LOD: 6.13 ppm) over other competing metal ions, in addition to visible colorimetric changes in the ZnGel upon metal encapsulation. The quenching ability of ZnGel remains unaltered for multiple cycles toward these environmental pollutants. The noteworthy quenching efficiency is attributed to a combination of static and dynamic fluorescence quenching and resonance energy transfer, which are in harmony with the DFT predictions. Thus, ZnGel provides a platform for the development of gel-based probes for diverse applications in the future. © 2023 The Royal Society of Chemistry.