Corrosion inhibition and statistical data of thiocarbanilide and thiocarbanilide admixed with 4-hydroxy-3-methoxybenzaldehyde on carbon steel in dilute acid media

Abstract

The inhibition performance of thiocarbanilide (TD) and thiocarbanilide admixed with 4-hydroxy-3-methoxybenzaldehyde (TDHM) on the corrosion of mild steel in 1M H2SO4 and HCl acid solutions was studied through coupon measurement. Data obtained showed the optimal performance of TD is 71.69% in H2SO4 and 83.14% HCl acid solution respectively. TDHM performed more effectively with optimal inhibition efficiency of 96.77% and 97.21% in both acids. The result showed the performance of corrosion inhibiting compounds improves through synergistic interaction with other compounds. However, exposure time and inhibitor concentration strongly influenced the performance of the compounds at varying degrees. Statistical data shows the standard deviation for inhibition efficiency of the compounds was significantly higher in H2SO4 compared to HCl due to the high degree of variation analogous to exposure time and stability of the inhibitor molecules. TD and TDHM generally showed lower standard of deviation, higher mean value, lower margin of error and higher proportion of inhibition efficiency data above 70% inhibition performance. Statistical data from analysis of variance depict both exposure time and inhibitor concentration is statistically relevant, and influences the inhibition performance of TD and TDHM compounds. However, the influence of concentration is significantly limited compared to exposure time with statistical relevance values above 60%