An investigation of three novel nonionic surfactants as corrosion inhibitor for carbon steel in 0.5M H2SO4

Abstract

► Novel nonionic surfactants as corrosion inhibitors for carbon steel in acidic medium. ► Inhibition efficiency increases by increasing the alkyl chains length attached to the molecules. ► Surfactants behaved as mixed type inhibitor and followed Langmuir adsorption isotherm. ► The inhibition action is mainly due to their mixture physical and chemical adsorption on the carbon steel surface. ► The synthesized novel nonionic surfactants were exhibited good surface properties. The inhibition effect of three novel nonionic surfactants, 2-((alkylimino)methyl)phenyl bis(53-hydroxy-3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,51-heptadecaoxatripentacontyl) phosphate (I–III), on the corrosion of carbon steel in 0.5 M H 2 SO 4 was studied by polarization, EIS and weight loss measurements. It was found that all the inhibitors were effective inhibitors and their inhibition efficiency was significantly increased with increasing both concentration and temperature. Polarization curves revealed that the used inhibitors represent mixed-type inhibitors. Adsorption of used inhibitors led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. Adsorption of used compounds was found to obey Langmuir isotherm and showed a chemical mechanism.