Insight into the anti-corrosion mechanism of Pisum sativum L leaves extract as the degradable inhibitor for Q235 steel in sulfuric acid medium

Background: In this work, we obtained Pisum sativum L leaf extract by soaking in sulfuric acid solution. Using sulfuric acid solution as solvent, the prepared Pisum sativum L leaf extract (PSLLE) has good solvent property and can be effectively dissolved in H2SO4 solution. Pisum sativum L leaf was selected as the research object, which is attributed to the large amount of Pisum sativum L cultivated in many countries and regions on the earth. Pisum sativum L leaf as a corrosion inhibitor, it can greatly realize the transformation of waste into treasure.Methods: The Tafel curve data manifest that PSLLE is mixed-type inhibitor, which concurrently delaying the anodic and cathodic reactions of working electrode in sulfuric acid environment. Surface topography test results prove that PSLLE can form the stabilized isolation film after adsorption of Q235 steel, and the corrosion of Q235 steel is significantly descend. Theoretical results indicate that the active ingredient in PSLLE can emerge high standard anti-corrosion nature.Significant findings: When the concentration of PSLLE is 600 mg/L, its corrosion inhibition efficiency can reach 95.9% at 298 K. With the increase of temperature, PSLLE can still show high anti-corrosion performance. The adsorption isotherm model data showed that there was chemical and physical co-adhesion of PSLLE onto the Q235 steel surface. The PSLLE adhesion at Q235 steel surface is consistent with Langmuir monolayer model.