Solvent Free Glycolysis of Plastic Waste as Green Corrosion Inhibitor for Carbon Steel in Sulfuric Acid

Abstract

Solvent free efficient green glycolysis of Polyethylene terephthalate waste, PET, in this respect, PET waste was subjected to depolymerization with propylene glycol in the presence of manganese acetate as a catalyst, the product is Bis-(3-hydroxy-propyl)-terephthalate, BHPT, as non-ionic surfactant was separated, characterized by FT-IR and 1HNMR, BHPT was evaluated as corrosion inhibitor for steel in the presence of 1.0 M sulfuric acid by chemical and electrochemical methods, the corrosion inhibition efficiency increase with inhibitor concentration and decrease with temperatures, the galvanostatic polarization curves indicate that the BHPT, compound act as mixed inhibitor, the impedance of the inhibited solution has increased with the increase in the concentration of the inhibitor. the inhibition due to adsorption of the inhibitor molecules on the steel surface, the adsorption obey Langmuir adsorption isotherm. Thermodynamic parameters were computed and discussed, Scanning electron microscope (SEM) was used to study the surface morphology of steel in absence and presence of the used inhibitor, hydrogen evolution techniques was used to evaluate the inhibition efficiency of the BHPT inhibitor compound. the data obtained from different techniques are in good agreement to each other and show the BHPT, surfactant derived from PET, waste considered as good corrosion inhibitor for steel in sulfuric acid.