j) 2016 - 39 Documents
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Item EXPERIMENTAL AND DENSITY FUNCTION THEORY CALCULATIONS TO INVESTIGATE THE ADSORPTION OF AN ANTI-INFLAMMATORY DRUG ON ALUMINUM SURFACE IN ACID SOLUTION(NACE - International Corrosion Conference Series, 2016-03-06) Monisha, R; Sowmya, RamkumarThe literature dealing with aluminium behavior in acid media in the presence of an anti-inflammatory drug is studied in order to understand its action mechanism, protective film formed and the possibility of its application according to the inhibition efficiency achieved. Aceclofenac, an anti-inflammatory drug is studied and its inhibitive performance on aluminium corrosion was studies by both dry and wet lab studies. Dry lab process using DFT is used to explore the relationship between the inhibitor molecular property and its inhibition efficiency. Wet lab studies have been carried out using weight loss, Tafel polarization and impedance measurements to evaluate their inhibitive performance in both 1M HCl and 0.5M H2SO4. PZC were calculated from impedance studies in order to understand the mechanism of inhibition. Polarization studies prove mixed type of inhibition. Good inhibition efficiency from weight loss studies was evidenced in both the acid medium, furnishing an inhibition efficiency of more than 80 %. The inhibition effect results from the adsorption of the inhibitor molecule via the lone pair of electrons on the hetero atoms together with the adjacent aromatic ring, on the metal surface forming a protective complex film. According to the results summarized, aluminium corrosion can be successfully inhibited by the drug used in the study in both the acid solutions. Results obtained from dry lab process are in good agreement with those recorded from wet lab experiments.Item CORROSION ABATEMENT IN ACID PICKLING INDUSTRIES BY EFFECTIVE N-HETEROCYCLIC COMPOUNDS: DRY AND WET LAB STUDIES(NACE - International Corrosion Conference Series, 2016-03-06) Sowmya, Ramkumar; Nalini, DDuring the chemical cleaning process using acids, in many electroplating and other descaling industries, there exists the problem of heavy metal loss. Hence there is always a need for abatement of this metal loss. A critical (steady state) value of the resistivity to corrosion of two organic compounds, 5-[2-(4-methoxyphenyl)-vinyl]-3-phenyl isoxazole (MVI) and 5-[2-(4-methoxyphenyl)-vinyl]-1,3,8-triazacyclopenta[ a]indene (MCI) were determined by a combination of non-electrochemical and electrochemical monitoring techniques. The behavior of organic compound, on a metallic alloy, i.e., mild steel, was investigated over a temperature range of 30 to 70°C. Efficiency of MVI and MCI were determined by correlating the electrochemical response of the compound (by electrochemical impedance and potentiodynamic polarization) in 1M HCl and 0.5M H2SO4 solution with their structural features. EIS measurement predicted the physical adsorption of both MVI and MCI on the metal surface from PZC calculation. Polarization studies proved that the inhibitors retard both the electrode process during inhibition. The integrity of the inhibitors efficiency with respect to time was assessed from mass loss measurements at different immersion period. Mass loss measurements proved that both MVI and MCI inhibit corrosion of mild steel in 1M HCl with a maximum efficiency of 91.07% and 78.23% at 20 ppm in HCl and H2SO4 respectively for MVI, 97.72% and 88.64% at 20 ppm in HCl and H2SO4 respectively for MCI. Hence MVI and MCI were found to be effective inhibitors for acid cleaning process in industries. The mechanism of the inhibition process was discussed in the light of the chemical structure and quantum chemical calculations of the investigated inhibitor. MVI and MCI were modeled in order to assess its absorbability using density functional theory (DFT) and revealed remarkably high interaction energies, which corroborate the experimental findings.