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Item LIRIOPE PLATYPHYLLA EXTRACT AS A GREEN INHIBITOR FOR MILD STEEL CORROSION IN SULFURIC ACID MEDIUM(Taylor & Francis Online, 2021) Ill-Min, Chung; Venkatesan, Hemapriya; Seung-Hyun, Kim; Kanchana, Ponnusamy; Natarajan, Arunadevi; Subramanian, ChitraThe phytochemical components of the methanol extract of Liriope platyphylla (L. platyphylla) leaves were identified using UHPLC, and their antioxidant activities were studied. The impact of the L. platyphylla extract on the corrosion of mild steel by 1 M H2SO4 was assessed using electrochemical and gravimetric techniques. L. platyphylla exhibited concentration-dependent corrosion protection activity through a mixed-mode adsorption process, as revealed by polarization studies. Impedance measurements indicated the development of a protective film of the inhibitor, which was confirmed by morphology studies at the micro level with scanning electron microscopy (SEM) and at the nano level with atomic force microscopy (AFM). Fourier transform infrared (FT-IR) studies also confirmed the adsorption of the inhibitor film onto the mild steel surface.Item INHIBITIVE EFFECT OF AN ALCOHOLIC EXTRACT OF A SEAWEED SARGASSUM MUTICUM IN CONTROLLING CORROSION OF MILD STEEL IN 0.5 N HCL(International Journal of Corrosion and Scale Inhibition, 2021-10-20) Jeslina, V; Kirubavathy, S J; Al-Hashem, A; Rajendran, S; Lacnjevac, C; Joany, R MThe inhibitive effect of an alcoholic extract of a seaweed, namely, Sargassum Muticum, in controlling corrosion of mild steel in 0.5 N HCl has been evaluated by weight loss method (immersion period 1 day) and electrochemical techniques such as polarization study and AC impedance spectra. The protective film has been investigated by AFM and Vickers Hardness test. Weight loss method reveals that 500 ppm of inhibitor offers 99% inhibition efficiency to mild steel immersed in 0.5 N HCl. The adsorption of inhibitor molecules on the metal surface follows Langmuir adsorption isotherm. The R2 value is very high, 0.998. Polarization study reveals that the corrosion potential is slightly shifted to anodic side. It is inferred that the inhibitor solution functions as mixed type corrosion inhibitor. In the presence of the inhibitor, the linear polarization resistance (LPR) increases and the corrosion current decreases. Because of the Blanket effect (formation of a protective film on the metal surface blocking the anodic sites and cathodic), electron transfer from the metal to the bulk of the solution is blocked. AC impedance spectra confirm the formation of a protective film on the metal surface. As the inhibitor concentration increases, the Rct value increases and the double layer capacitance (Cdl) decreases, the impedance increases and the phase angle increases due to the blocking effect on the metal surface. It is found to be a monolayer of protective film. The Vickers hardness of the inhibited metal surface is lower than that of polished metal but higher than that of corroded surface. The average roughness, RMS roughness and maximum peak-to-valley height of inhibited metal surface are lower than those of corroded metal surface but higher than those of polished metal surface. The outcome of the study may be used in pickling industry where HCl is used to remove rust and at the same time metal surface is protected.Item ANTI-CORROSIVE POTENTIAL OF CYPERUS ROTUNDUS AS A VIABLE CORROSION INHIBITOR FOR MILD STEEL IN SULPHURIC ACID(Emerald Publishing Limited, 2020-06-05) Rajan, Anitha; Chan Basha, Nusrath Unnisa; Venkatesan, Hemapriya; Selvaraj, Mohana Roopan; Subramanian, Chitra; Chung, ll-Min; Seung-Hyun, Kim; Prabakaran, MayakrishnanOver the past decade, plant extracts are ultimate green candidatures to substitute the expensive and noxious synthetic corrosion inhibitors. In this regard, this study aims to focus on evaluating anti-corrosion properties of green inhibitor Cyperus rotundus (C. rotundus), a perennial herb found throughout India.Item ECOFRIENDLY GREEN INHIBITOR FROM HEMEROCALLIS FULVA AGAINST ALUMINUM CORROSION IN SULPHURIC ACID MEDIUM(Taylor & Francis Online, 2020-01-15) Ill-Min, Chung; Ramalingam, Malathy; Seung-Hyun, Kim; Kathirvel, Kalaiselvi; Mayakrishnan, Prabakaran; Mayakrishnan, GopiramanThis research work aims to identify a non-toxic, cheap, and effective greener inhibitor from Hemerocallis fulva (H. fulva) for corrosion of aluminum in a 1 M H2SO4 medium at different concentrations and temperatures. We investigated the inhibitive effect of H. fulva extract in a 1 M H2SO4 solution on aluminum using weight loss measurements with various concentrations and temperatures. Evaluations of the mechanism of corrosion inhibition by potentiodynamic polarization and AC-impedance analysis were also performed. The nature of the adsorption and morphology on the surface of aluminum were performed by atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) studies. The results suggested that the H. fulva extract can be used on aluminum as an efficient eco-friendly corrosion inhibitor in 1 M H2SO4 solution as identified using weight loss because the maximum corrosion inhibition efficiency η (%) was found to be 89% at 600 ppm at 303 ± 1 K. It was found that maximum η (%) was obtained at 303 ± 1 K compared to other temperatures (313, 323, and 333). The activation energy (Ea) was higher in the presence of inhibitor than in the absence of inhibitor, showing the temperature dependency of inhibition. The positive values of enthalpy of activation ΔH° and entropy of activation ΔS° reflect the endothermic and disordered nature of the reaction. Physical adsorption was proposed for the inhibition and the process followed the Langmuir adsorption isotherm. The negative value of ΔGoads indicates spontaneous adsorption. Polarization measurements clearly indicated that the H. fulva acts as a mixed inhibitor and the η (%) increases with inhibitor concentration. SEM-EDX, AFM, and XPS studies confirmed the formation of a protective layer over the surface of the aluminum specimen.Item UTILIZATION OF BIOWASTE AS AN ECO-FRIENDLY BIODEGRADABLE CORROSION INHIBITOR FOR MILD STEEL IN 1 MOL/L HCL SOLUTION(Elsevier, 2020-12) Venkatesan, Hemapriya; Mayakrishnan, Prabakaran; Subramanian, Chitra; Manoharan, Swathika; Seung-Hyun, Kim; Ill-Min, ChungThis report focuses on the application of a biodegradable biowaste [human hair-(HHR)], to produce a mild steel corrosion inhibitor. The performance of HHR extract in inhibiting metallic corrosion in 1 mol/L HCl was investigated. The analysis of the metal corrosion behavior using electrochemical and weight loss techniques revealed that HHR exhibits an efficient corrosion-mitigating effect via adsorption on the metal surface following a Langmuir isotherm. Tafel-plot results revealed the mixed-mode corrosion protection behavior of HHR. Surface analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy provided evidence for the precipitation of a protective HHR film on the metal surface.Item THE INFLUENCE OF SWELLING ON ELASTIC PROPERTIES OF POLYACRYLAMIDE HYDROGELS (Article)(Frontiers in Materials, 2020-07-23) Ramesh, Subramani; Alicia, Izquierdo-Alvarez; Pinaki, Bhattacharya; Mathieu, Meerts; Paula, Moldenaers; Herman, Ramon; Hans Van, OosterwyckPolyacrylamide (PAM) hydrogels are commonly used as substrates for cell mechanical and mechanobiological studies because of their tunable stiffness and ease of handling. The dependence of bulk rheological and local elastic properties (assessed by Atomic Force Microscopy, or AFM) of PAM hydrogels on its composition and polymerization temperature has been extensively studied. PAM hydrogels swell when immersed in media, but the influence of swelling on local elastic properties is poorly characterized. Direct measurements of the effect of swelling on PAM elastic properties are scarce. We report here, for the first time, the direct measurements of volumetric swelling and local elastic properties of PAM gels throughout the post-polymerization swelling process until equilibrium. First, local and global elastic properties (measured by rheology), were obtained during polymerization in the absence of swelling, and showed good agreement with each other. Four PAM hydrogel compositions were characterized thus, with corresponding storage shear moduli (as measured immediately after polymerization) of 4,530 Pa (termed stiffest), 2,900 Pa (stiff), 538 Pa (soft), and 260 Pa (softest). Next, all compositions were subjected to swelling in phosphate buffered saline. Swelling ratios and local elastic moduli were measured at 0, 3, 6, 9, 12, and 24 h post-polymerization for the soft and softest compositions, and once daily till 6 days post-polymerization for all four compositions. For the stiffest and stiff gels, swelling ratio, and local elastic modulus changed negligibly with time, while for the soft and softest gels, substantial changes between Day 0 and Day 1 were found for both swelling ratio (increased by 21.6 and 133%, respectively), and local elastic modulus decreased (by 33.7 and 33.3%, respectively), substantially. Experimental data were analyzed by a model that combined ideal elastomer mechanics and poroelastic swelling kinetics model. Model predictions confirmed the validity of present measurements with respect to past studies where swelling and elastic properties were not measured simultaneously. The present study underlines the important effect swelling can have on PAM elastic properties and provides detailed quantitative data to guide the duration taken to reach equilibrium—a useful information for cell mechanics experiments. In addition, the simultaneous measurements of swelling and local elastic moduli provide novel data for the validation of theoretical models.Item INHIBITIVE EFFECT OF AN ALCOHOLIC EXTRACT OF A SEAWEED SARGASSUM MUTICUM IN CONTROLLING CORROSION OF MILD STEEL IN 0.5 N HCL(International Journal of Corrosion and Scale Inhibition, 2021-10-20) Jeslina, V; Kirubavathy, S J; Al-Hashem, A; Rajendran, S; Lacnjevac, C; Joany, R.M.The inhibitive effect of an alcoholic extract of a seaweed, namely, Sargassum Muticum, in controlling corrosion of mild steel in 0.5 N HCl has been evaluated by weight loss method (immersion period 1 day) and electrochemical techniques such as polarization study and AC impedance spectra. The protective film has been investigated by AFM and Vickers Hardness test. Weight loss method reveals that 500 ppm of inhibitor offers 99% inhibition efficiency to mild steel immersed in 0.5 N HCl. The adsorption of inhibitor molecules on the metal surface follows Langmuir adsorption isotherm. The R 2 value is very high, 0.998. Polarization study reveals that the corrosion potential is slightly shifted to anodic side. It is inferred that the inhibitor solution functions as mixed type corrosion inhibitor. In the presence of the inhibitor, the linear polarization resistance (LPR) increases and the corrosion current decreases. Because of the Blanket effect (formation of a protective film on the metal surface blocking the anodic sites and cathodic), electron transfer from the metal to the bulk of the solution is blocked. AC impedance spectra confirm the formation of a protective film on the metal surface. As the inhibitor concentration increases, the Rct value increases and the double layer capacitance (Cdl) decreases, the impedance increases and the phase angle increases due to the blocking effect on the metal surface. It is found to be a monolayer of protective film. The Vickers hardness of the inhibited metal surface is lower than that of polished metal but higher than that of corroded surface. The average roughness, RMS roughness and maximum peak-to-valley height of inhibited metal surface are lower than those of corroded metal surface but higher than those of polished metal surface. The outcome of the study may be used in pickling industry where HCl is used to remove rust and at the same time metal surface is protected.