Recycling and evaluation of poly(ethylene terephthalate) waste as effective corrosion inhibitors for C-steel material in acidic media

• R.J. Tuama¹, M.E. Al-Dokheily² and M.N. Khalaf³

¹ Department of Pharmacognosy, College of Pharmacy, ThiQar University, Iraq
² Department of Chemistry, College of Science, ThiQar University, Iraq
³ Department of Chemistry, College of Science, Basrah University, Iraq

Abstract: Depolymerization of waste polyethylene terephthalate (PET) was achieved by propane-1,3-dithiol into bis(3-mercaptopropyl)thioterephthalate (BTPTT) product. The product was characterized by FTIR and GPC. The thermal properties (TGA, DTA) indicated that the prepared compound was thermally stable up to 150°C. The corrosion inhibition efficiency of the new compound as a corrosion inhibitor was evaluated for carbon steel in 0.1 N HCl as a corrosive environment and the inhibitor concentration was (0, 5, 10, 15, 20 and 25 ppm). The inhibition efficiency was measured by using Tafel plot in electrochemical technique. The results indicated that the effectiveness of the bis(3-mercaptopropyl)thioterephthalate as an inhibitor increases with the concentration but this characteristic is inversely related to the temperature. The inhibition efficiency (%IE) reached 97.32% for the 25 ppm concentration at 298 K. Potentiodynamic polarization measurements revealed that the product is a corrosion inhibitor of anodic type. The results showed that the inhibition occurs through adsorption of the inhibitor molecules on the C-steel surface. The adsorption of (BTPTT) on C-steel surface obeys the Langmuir adsorption isotherm and involves a chemisorption mechanism.

Keywords: depolymerization, PET, corrosion inhibitor, adsorption isotherm

Int. J. Corros. Scale Inhib., 2020, 9, no. 2, 427-445 PDF (699 K)
doi: 10.17675/2305-6894-2020-9-2-3

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