Experimental and theoretical investigations of 1,1′-Dibenzyl-[4,4′-bipyridine]−1,1′-diium chloride as effective corrosion inhibitor for Q235 steel in 1 M HCl

Abstract

The addition of corrosion inhibitors has been extensively used as the simplest, most effective and inexpensive technique to inhibit corrosion in industry, and for this reason, this study investigated how 1,1′-Dibenzyl-[4,4′-bipyridine]− 1,1′-diium chloride (DBDC) affected Q235 carbon steel's ability to resist corrosion in 1 M HCl. The experimental study was conducted to determine how the compound suppresses corrosion of carbon steel by electrochemical techniques, and the findings demonstrated that DBDC is a powerful corrosion inhibitor that can stop Q235 carbon steel from corroding. Electrochemical impedance spectroscopy (EIS) results indicated that DBDC at a concentration of 400 ppm had a corrosion inhibition efficiency of 95.83% at 298 K ambient temperature. The polarization curves suggested that DBDC could act as a mixed inhibitor and reduce the corrosion current density. The adsorption of compound on Q235 steel surface conformed to Langmuir isothermal adsorption line, and the related thermodynamic parameters were discussed, as well as the influence of the analyzed temperature on efficiency of corrosion inhibition. The surface morphology of Q235 carbon steel was examined under different corrosion inhibitor conditions, the results confirmed that the inhibitor can adsorb on the surface of carbon steel to form a protective film. The role of DBDC molecular structure in the corrosion inhibition process was surveyed by theoretical calculation methods, the results showed that the DBDC molecule could be adsorbed on metal surface by pyridine ring and benzene ring.