Thermodynamic and kinetic investigations of corrosion inhibition behavior of 2-MBT on steel in pH=8

Document Type: Research Paper

Authors

1 Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran

2 Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran

Abstract

Corrosion can cause dangerous and expensive damage to everything from pipelines to vehicles, water and wastewater systems, and even home appliances. The use of organic inhibitors is one of the most widely practical methods for protection of metals and alloys against corrosion. The inhibition ability of 2-Mercaptobenzothiazole as an inhibitor against the corrosion of C-steel in 2 M NaCl solution was evaluated by Tafel polarization. 2-Mercaptobenzothiazole retards both the cathodic and anodic reaction through chemical and physical adsorption and blocking the active corrosion sites. Polarization curves showed that the inhibition efficiency increases up to 70% with increase in inhibitor concentration in room temperature and increase with rise in temperature. The adsorption of 2-Mercaptobenzothiazole obeyed the Langmuir adsorption isotherm. The enthalpies of activation were calculated around +50 kj mol-1. The positive signs of the enthalpies of activation process ΔH reflect the endothermic nature of the steel dissolution process. The calculated 〖∆G〗_ads values are ranging between -32.69 and -35.81 kJ mol_1, indicating that the adsorption mechanism is both electrostatic adsorption and chemisorption. The entropy of adsorption was calculated 78 j mol-1 K-1 which indicated the increase in the solvent entropy and more positive water desorption entropy.

Keywords



Articles in Press, Accepted Manuscript
Available Online from 17 January 2018
  • Receive Date: 04 January 2015
  • Revise Date: 21 April 2015
  • Accept Date: 04 July 2015