Combating A36 mild steel corrosion in 1 M H2SO4 medium using watermelon seed oil inhibitor

Abstract

>Corrosion inhibitive performance of the extracted watermelon seed oil on A36 mild steel in 1 M H2SO4 medium, at 305 and 319 K corrosion reaction temperatures, was investigated. Weight loss and inhibition efficiency were determined using gravimetric method while corrosion rate and inhibitoion efficiency were evaluated using potentiodynamic tests. Gravimetric tests showed that watermelon seed oil inhibitor attained a better corrosion inhibition efficiency of 50% at the operating temperature of 305 K compared to an efficiency of 48% obtained at the operating temperature of 319 K. Electrochemical potentiodynamic polarization tests showed that 3 vol/vol% inhibitor concentration gave the most promising corrosion inhibiting results at the operating temperature of 305 K, while 4 vol/vol% inhibitor concentration gave the most reliable corrosion resisting one at the operating temperature of 319 K. Langmuir adsorption isotherm correctly predicted the adsorption behaviour of the watermelon seed oil on A36 mild steel surface in 1 M H2SO4 medium. the negative values of ∆Gads revealed the spontaneous adsorption nature of the inhibitor on the mild steel surface and the electrochemical potentiodynamic polarization results showed that the watermelon seed oil acted as a mixed-type corrosion inhibitor. The optical image analysis revealed both the potency level of watermelon seed oil as an inhibitor as well as the optimum inhibitor concentrations of 3 vol/vol% (at 305 K) and 4 vol/vol% (at 319 K)

Keywords

• corrosion
• inhibitor
• mild steel
• watermelon seed oil
• weight loss