Chondroitin sulfate as potent green corrosion inhibitor for mild steel in 1 M HCl

Abstract

Chondroitin sulfate (CS) was studied as an effective green corrosion inhibitor for mild steel in 1 M HCl using gravimetric (303–333 K), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), SEM/EDAX, FT-IR, UV–Visible spectroscopy, DFT analysis and molecular dynamics (MD) simulation. The gravimetric parameters revealed that inhibition efficiency depends both on the temperature of corrosive solution and concentration and further supports its long term stability in aggressive solution. The maximum %IE of 95.4% is observed at concentration of 500 ppm at 333 K. PDP analysis suggests that compound acts as mixed type of inhibitor with anodic dominance. EIS data revealed the formation of a protective film by the adsorbed inhibitor. SEM/EDAX studies adequately supported the existence of protective layer on mild steel surface in inhibited acid solution. The binding of Chondroitin sulfate with mild steel surface in aggressive acid solution was further supported by DFT and MD simulation studies.