Electrochemical and Economic Evaluation of the Cocoa Bean Shell as a Corrosion Inhibitor in Acidic Medium

Abstract

The inhibition effect of the cocoa bean shell powder (CBSP) on SAE 1008 carbon steel was studied in acidic medium (HCl 0.5 mol L-1) by electrochemical techniques and gravimetric measurements. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to the chemical and morphological characterization. The gravimetric and EIS results showed that the corrosion rate decreases with increasing inhibitor concentration, reaching the maximum value of 97.92% in 1.77 g L-1 inhibitor (highest concentration studied). Even at the lowest concentration (0.44 g L-1) good corrosion inhibition efficiency (96.03%) was observed. The polarization curves indicated that the CBSP acts as a mixed type inhibitor. The inhibitory molecules adsorption followed the Langmuir isotherm model. The inhibitor economic evaluation showed that the use of CBSP is 48-616 times cheaper than traditional inhibitors. The results showed that CBSP is an efficient corrosion inhibitor for carbon steel and its production is financially attractive.