The Response Surface Method as an Experimental Design Technique to Explore and Model the Performance of Corrosion Inhibitors

Numerous environmental factors strongly affect performance of inhibitors. Therefore, many experimental tests and much time are needed to fully explore the inhibitor performance in various conditions. This paper introduces the response surface method using central composite face-centered design as a method in order to explore and mathematically model the inhibitors' behavior in different working conditions. Also, this method provides the ability of significantly decreasing the number of experiments. In this study, as an example, the effect of temperature, hydrochloric acid, and inhibitor concentrations on inhibitive behavior of 4-aminophenyl disulfide for mild steel was examined. Further, two mathematical models were established to estimate mild steel corrosion rate in the inhibited and uninhibited solutions. Analysis of variance was applied to check the adequacy of the models. Finally, the Langmuir adsorption energy was calculated using the acquired models. The results showed that, despite the inhibitor efficiency changes in various conditions, the adsorption type into metal is an invariable parameter.