Computational Modeling and Statistical Analysis on the Corrosion Inhibition of Aluminium in Nitric Acid Solution by Ethanolic Extract of Citrus Sinesis Seed (Published)
The purpose of this paper is to study the inhibition potential of ethanol extract of Citrus Sinesis Seed (CSS) on the corrosion of mild steel in 1M HCl using phytochemical screening, conventional weight loss, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and Quantum chemical analysis. The experimental results revealed that the Inhibition efficiency of the Citrus Sinesis seed extract increases with extracts concentration but decreases with time and temperaturein. The inhibition efficiency increases gradually reaching a maximum value of 96.72% within the first 2 hours at a concentration of 1.0g/l. the extract acts as an inhibitor because of its phytochemical composition and is adsorbed spontaneously on the surface of aluminium according to Langmuir adsorption isotherm. The mechanism of physical adsorption is proposed from the inhibition efficiency with temperature and the values of some kinetic and thermodynamic parameters were obtained. FTIR results showed that the inhibition mechanism was an absorption process through the functional groups present in the seed extract. Surface morphology also revealed that corrosion product confirmed the protection offered by the extract on the surface of the metal immersed in the acid media. Quantum chemical studies confirmed that inhibition was due to adsorption of active molecules leading to formation of a protective layer on surface of mild steel.
This paper presents a corrosion rate model for mild steel in hydrochloric acid. A non-linear corrosion rate equation was developed, validated and used to relate the acid point, pH of hydrochloric acid as corrosive medium for mild steel to other variables like corrosion rate and substrate immersion period. The inhibitor used is Sinclair synthetic paint – an organic inhibitor. The effect of variables on corrosion rate has been investigated using non-linear regression analysis. The derived model is an exponential decay function of two input factors. The coefficient of correlation between the calculated and experimental data indicates good performance of the derived model.
Anticorrosion Activity of Cactus Powder on Iron Metal Sheets (Published)
The anticorrosion activity of CE on iron metal sheets was investigated using weight loss method. The result revealed that the rate of corrosion activity is decreased from 7.887×10-3 to 1.7×10-3 mmpy with increasing dose of inhibitors from 0mL to 9mL. But the inhibition efficiency and surface coverage area are increased from 49% to 77% and 0.49 to 0.77, respectively with increasing inhibitor dose from 1mL to 9mL. This is due the fact that as the concentration of inhibitors increased, a larger number of inhibitors molecule is get adsorbed on the metal surface which results more coverage of the corroded metal surface. This makes the metal too difficult from further corrosion by the corrosion agents. In the other hand, the inhibition efficiency and surface coverage area of CE are lower at higher temperature. This is due to the fact that at an elevated temperature desorption of pre-adsorbed inhibitor molecules occur from metal surface; decomposition and rearrangement of some inhibitors may take place which increases corrosion rate at uninhibited metal surface. Adsorption of CE on iron metal sheets are obeyed the Langmuir, Temkin and Frumkin adsorption isotherms. The positive value of activation energy (Ea) and the negative value of free energy of adsorption (ΔGoad) support the physical adsorption of CE iron metal sheets. The large values of the thermodynamic parameters at high dose of CE indicate the stable interaction between CE and iron metal sheets.
Corrosion Inhibitive Effects of Coconut (Cocos Nucifera Linn) Water For Mild Steel in Acidic Medium (Published)
The corrosion inhibitive effect of coconut water as an eco-friendly inhibitor for the corrosion control of mild steel in 0.5 Molar solution of H2SO4 acid have been investigated using the weight loss method which is considered more informative than other laboratory techniques. The studies were carried out using 30-110ml of the coconut water. The test coupons were totally immersed in the corroding medium containing various concentration of the inhibitor at the time intervals of 24-192 hours. The results obtained showed that the concentration of the inhibitor in the corrodent impacted differently on the test coupons. The corrosion rate was found to decrease while the inhibitor efficiency increases as the inhibitor concentration was increased. The plateau of maximum inhibition efficiency of 89.07% and 81.57% was obtained at the concentration of 90ml and 110ml for 24hours and 48hours immersion time respectively. The study showed that coconut water possesses inhibiting properties for reducing the corrosion of mild steel in the acidic medium.