j) 2016 - 39 Documents
Permanent URI for this communityhttps://dspace.psgrkcw.com/handle/123456789/4006
Browse
Search Results
Item RHUS VERNICIFLUA AS A GREEN CORROSION INHIBITOR FOR MILD STEEL IN 1 M H2SO4(Royal Society of Chemistry, 2016-06-08) Mayakrishnan, Prabakaran; Seung-Hyun, Kim; Venkatesan, Hemapriya; Mayakrishnan, Gopiraman; Ick Soo, Kim; Ill-Min, ChungThe methanolic extract of the plant Rhus verniciflua was examined as a corrosion inhibitor for mild steel in 1 M H2SO4 through weight loss measurements, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The sample surface morphology was analyzed using scanning electron microscopy/energy-dispersive X-ray spectroscopy. The total phenolic content of the R. verniciflua leaf extract was found to be 158 mg g−1, while the total flavonoid content was 19.65 mg g−1. Eleven phenolic compounds, three flavonoid compounds, five derivatives of hydroxycinnamic acid, and four hydroxybenzoic acids were identified in the extract. Polarization studies showed that the R. verniciflua plant extract acts as a good mixed-type inhibitor. The inhibition efficiency was found to increase with an increase in the inhibitor concentration. On the other hand, the inhibition efficiency decreased with an increase in the temperature. The adsorption of the plant extract constituents is discussed based on the Langmuir, Temkin, and El-Awady isotherms. Moreover, the adsorption and thermodynamic parameters corresponding to extract adsorption onto mild steel were calculated and are discussed. The results show that the R. verniciflua plant extract can be employed as an effective corrosion inhibitor with good anticorrosion properties for metals in acidic environments.Item HIGHLY EFFICIENT LIGULARIA FISCHERI GREEN EXTRACT FOR THE PROTECTION AGAINST CORROSION OF MILD STEEL IN ACIDIC MEDIUM: ELECTROCHEMICAL AND SPECTROSCOPIC INVESTIGATIONS(Elsevier, 2016-02) Mayakrishnan, Prabakaran; Seung-Hyun, Kim; Kathirvel, Kalaiselvi; Venkatesan, Hemapriya; Ill-Min, ChungA methanol extract of Ligularia fischeri was studied for its inhibitive effect on the corrosion of mild steel in a 1 M hydrochloric acid medium, using the metrics of weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The corrosion rate of mild steel and Ligularia fischeri's inhibition efficiencies were calculated. The inhibition efficiency [η (%)] was observed to increase with increasing concentrations of Ligularia fischeri. A maximum inhibition efficiency of 92% was achieved using 500 ppm of the inhibitor. The weight loss experiments were performed at different temperatures to understand the thermodynamic mechanism of inhibition. A mixed inhibition mechanism was proposed for the effects of Ligularia fischeri extract, as revealed by the potentiodynamic polarization technique. A solution analysis by atomic absorption spectroscopy (AAS) for mild steel showed decreased dissolution of iron in the presence of Ligularia fischeri. The adsorption mechanism and surface morphology of the mild steel, both with and without the inhibitor, were studied using UV–visible, Fourier transform infrared (FT-IR), Raman, wide-angle X-ray diffraction (WAXD), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS), and atomic force microscopy (AFM).Item TRAGIA PLUKENETII EXTRACT AS AN ECO-FRIENDLY INHIBITOR FOR MILD STEEL CORROSION IN HCL 1 M ACIDIC MEDIUM(Springer Link, 2016) Mayakrishnan, Prabakaran; Seung-Hyun, Kim; Venkatesan, Hemapriya; Ill-Min, ChungA Tragia plukenetii (T. plukenetii) plant extract for use as a low-cost and efficient corrosion inhibitor for mild steel (MS) in 1 M HCl medium has been studied using various methods involving weight loss calculation, electrochemical impedance spectroscopy, and Tafel polarization. The maximum corrosion inhibition efficiency was found to be 88 % at 500 ppm. It was found that the T. plukenetii extract’s inhibition efficiency increased with the inhibitor concentration. The polarization measurement showed that the T. plukenetii plant extract acts as good mixed-type inhibitor. Thermodynamic investigations showed the change in enthalpy, entropy, and free energy. The adsorption mechanism of the extract was investigated using UV–Visible, FT-IR, Raman spectroscopy, and wide-angle X-ray diffraction studies. The inhibitor solution, investigated on the basis of the atomic absorption spectra for MS, revealed decreased dissolution of Fe in the presence of the plant extract. Surface analysis of the metal with and without the plant extract was carried out by using scanning electron microscopy and energy-dispersive X-ray spectroscopy.Item EVALUATION OF POLYPHENOL COMPOSITION AND ANTI-CORROSION PROPERTIES OF CRYPTOSTEGIA GRANDIFLORA PLANT EXTRACT ON MILD STEEL IN ACIDIC MEDIUM(Elsevier, 2016-05-25) Mayakrishnan, Prabakaran; Seung-Hyun, Kim; Venkatesan, Hemapriya; Ill-Min, ChungThe total phenolic and flavonoid compounds present in Cryptostegia grandiflora leaf extract were analyzed. The results confirmed that the extract contains the Myricetin 3582.22(μg/g) and Rutin 45.62(μg/g) as major components. C. grandiflora extract was evaluated for its anti-corrosion property on mild steel in 1 M H2SO4. A maximum inhibition efficiency of 87.54% was achieved by using 500 ppm of the inhibitor. Polarization studies indicate that the extract acts as a mixed inhibitor. The formation of productive layer on mild steel by inhibitor was confirmed by SEM-EDS and AFM. The extract is adsorbed on the mild steel according to Temkin adsorption isotherm.Item DRY AND WET LAB ANALYSIS ON BENZOFUSED HETEROCYCLIC COMPOUNDS AS EFFECTIVE CORROSION INHIBITORS FOR MILD STEEL IN ACIDIC MEDIUM(Elsevier, 2016-08-25) Venkatesan, Hemapriya; Mayakrishnan, Prabakaran; Kandasamy, Parameswari; Subramaniyan, Chitra; Seung-Hyun, Kim; Ill-Min, ChungThe influence of two benzofused heterocyclic compounds, namely 2-phenylquinazolin-4(3H)-one(PQO) and 2-phenyl-4H-benzo[d]oxazin-4-one(POO) in controlling mild steel corrosion in 1 M H2SO4 solution was investigated using gravimetric and electrochemical methods. The experimental results revealed that both the inhibitors inhibit corrosion and their inhibition efficiency follows the order PQO > POO. A mixed mode of inhibition from polarization and a charge transfer mechanism from impedance study in the absence and presence of inhibitors were found. The passive film formed on the mild steel surface was characterized using SEM-EDX. Quantum chemical parameters derived using DFT performed at B3LYP/6-31G(d, p) level were used to correlate the molecular structure.