Evaluation of cactus mucilage as a green corrosion inhibitor for copper in sulfuric acid environment

This study investigates the corrosion inhibition performance of cactus mucilage for copper in 0.5 M H2SO4 solution. The cactus mucilage was extracted using a pure water extraction method and characterized using FTIR and GC-MS analyses. The inhibition efficiency was evaluated using potentiodynamic polarization and EIS techniques, while surface morphology was analyzed using SEM and AFM. The potentiodynamic polarization results revealed that cactus mucilage acts as a mixed-type inhibitor, with inhibition efficiency increasing from 78.6% at 100 mg L-1 to 94.5% at 600 mg L-1. The EIS measurements showed a significant increase in charge transfer resistance from 0.56 k? cm-2 in the uninhibited solution to 8.26 k? cm-2 with 600 mg L-1 cactus mucilage. The adsorption of cactus mucilage on the copper surface followed the Langmuir isotherm model, with a strong adsorption equilibrium constant of 23.6 × 103 M. Compared to other green inhibitors, cactus mucilage exhibited superior inhibition efficiency and sustainability advantages, making it a promising eco-friendly alternative for copper corrosion protection.