Excellent corrosion inhibition performance of novel quinoline derivatives on mild steel in HCl media: Experimental and computational investigations

Abstract

The inhibition performance of two synthesized quinoline derivatives: 6-benzylquinoline (BQ) and 6-(quinolin-6-ylmethyl) benzene-1,2,3,4,5-pentasulfonic acid (QBPA) on mild steel in 1 M HCl has been investigated through weight loss, electrochemical measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). All experimental results indicated that BQ and QBPA extremely enhanced the corrosion resistance of mild steel and QBPA showed a better inhibitive performance than BQ. The results of potentiodynamic polarization illustrated that BQ and QBPA performed as mixed-type inhibitors. Langmuir adsorption isotherm was well fitted for the adsorption of BQ and QBPA on mild steel surface with a competitive physisorption and chemisorption mechanism. The results of quantum chemical calculations and molecular dynamic simulations showed that benzene rings of both BQ and QBPA adsorbed on the metal surface in distinct gradient direction and quinoline ring of both BQ and QBPA adsorbed nearly parallel on the steel surface.