Gravimetric and electrochemical studies of the control of aluminum deterioration in HCl using Ukpo clay - polyaniline as inhibitor
1 Material and Energy Technology Department, Projects Development Institute (PRODA), Emene, Enugu, Nigeria.
2 Department of Chemical Engineering, Enugu State University of Science and Technology, Agbani, PMB 01660, Enugu, Nigeria.
3 Department of Chemical Engineering, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
Research Article
Global Journal of Engineering and Technology Advances, 2024, 21(03), 178-189.
Article DOI: 10.30574/gjeta.2024.21.3.0214
Publication history:
Received on 09 October 2024; revised on 27 December 2024; accepted on 30 December 2024
Abstract:
This study presents the use of Ukpo clay- polyaniline as inhibitor to control deterioration of aluminium in HCl. The substance (inhibitor) was characterized using gas chromatography-mass spectrophotometer. Gravimetric (weight loss) and electrochemical (potentiodynamic polarization and electrochemical impedance spectroscopy) techniques were employed in the corrosion control procedure. Analyses of the experimental results showed that Ukpo clay/polyaniline composite contains chemical constituents (2-cyclopropyl-2-methyl-n-(1-cyclopropylethyl), 2-bromo-4-fluorophenyl ester, bis(2-ethylhexyl) phthalate, piperidine-4-carbonitrile) suited for the deterioration control of Al in HCl. For the gravimetric analysis, the corrosion inhibition process was found to be spontaneous, exothermic, and in agreement with physical adsorption mechanism. The activation energy of inhibition was less than the critical values of 80kJ/mol, and Langmuir adsorption isotherm best described the inhibition procedure. The relationship between inhibition efficiency of Ukpo clay - polyaniline composite and factors of inhibitor concentration, temperature and time is a quadratic model. Electrochemical analysis of the study revealed that Ukpo clay/polyaniline composite acted as mixed-type inhibitor. It inhibited both cathodic and anodic reactions. Adding the inhibitor to the HCl medium enhanced the magnitude of the impedance spectrum, which indicates high inhibiting strength of the inhibitor’s constituents in impeding the invasion of the electrochemical reaction. Thus, Ukpo clay - polyaniline composite should be applied as a viable corrosion inhibitor of aluminium in hydrochloric acid environment.
Keywords:
Ukpo clay; Polyaniline; Inhibitor; Aluminium; HCl medium
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