Polyethylene glycol and polyvinylpyrrolidone: potential green corrosion inhibitors for copper in H2SO4 solutions

Weight-loss, thermometric, and electrical conductance techniques were employed for the investigation of the influence of polyethylene glycol 400, 4000, and polyvinylpyrrolidone K15 as cost-effective, efficient, and eco-friendly inhibitors on the corrosion inhibition of copper in H2SO4 solution. The corrosion rates of copper in H2SO4 solutions increase with an increase in acid concentrations and temperatures in the absence of inhibitors. The addition of PEG 400, PEG 4000, and PVP K15 to the corrosive solutions was found to have a considerable inhibitory influence on the corrosion rates of copper at various temperatures. Consequently, the inhibition efficiency of PEG 400, PEG 4000 and PVP K15 increases with an increase in their concentrations. Remarkably, PVP K15 was a more efficient inhibitor than PEG 400, and PEG 4000, this effect might be attributed to the nature of the functional groups and the size of the PVP K15 chains. An evaluation of the temperature effect was studied to show that rising temperatures lead to an increased corrosion rate and lower inhibition efficiencies. However, PEG 400, PEG 4000, and PVP K15 inhibited copper corrosion by virtue of adsorption, which was found to accord with the Langmuir and Temkin adsorption isotherm models. Moreover, the thermodynamic aspects (Delta H0, Delta S0 and Ea) of the adsorption process were calculated and discussed.