Seed Shells as Active and Nontoxic Corrosion Inhibitors for Aluminum in Aggressive Acid Environment

Chemical (weight loss and thermometric) measurements were used to study the corrosion inhibition characteristics of five seed shells, namely Afzelia africana seed shell (AASS), Brachystegia eurycoma seed shell (BESS), Derium microcarpum seed shell (DMSS), Mucuna flagellipes seed shell (MFSS) and Pentaclethra macrophlla seed shell (PMSS), respectively, on the inhibition of aluminum corrosion in aggressive 2.0 % HCl solutions at 30 and 50 °C for 8 hrs. Weight loss and thermometric measurements demonstrated that the seed shells (AASS, BESS, DMSS, MFSS and PMSS extracts) act as good corrosion inhibitors. Addition of the seed shell extracts decreases the corrosion rate of the process thereby improving inhibition performance. The result also reveals that the five seed shell extracts adsorb on the Aluminum surface through physical adsorption in accordance with Flory-Huggins and Langmuir adsorption isotherms at all temperatures investigated. Kinetic-thermodynamic parameters indicate a spontaneous adsorption process. Results of inhibition efficiency demonstrates that DMSS extract performed better as compared to BESS, AASS, PMSS and MFSS extracts.