Aryl sulfonamidomethylphosphonates as new class of green corrosion inhibitors for mild steel in 1Â M HCl: Electrochemical, surface and quantum chemical investigation

Synthesis and corrosion inhibition property of five aryl sulfonamidomethylphosphonates in 1 M HCl are reported using chemical, electrochemical, scanning electron microscopy (SEM) and quantum chemical calculation methods. Experimental results show that aryl sulfonamidomethylphosphonates are good corrosion inhibitors for mild steel in 1 M HCl and their inhibition efficiency increases with concentration. Potentiodynamic polarization studies show that studied inhibitors act as mixed type and their adsorption on mild steel surface obeys the Langmuir's adsorption isotherm. The thermodynamic (Ea, ΔH⁎, ΔS⁎, ΔG0ads) and quantum chemical parameters were calculated and discussed to describe the mechanism of adsorption.