Synergistic inhibition of benzotriazole and sodium D-gluconate on steel corrosion in simulated concrete pore solution

Herein, the synergistic inhibition of two typical corrosion inhibitors benzotriazole (BTA) and sodium D-gluconate (SD) on the corrosion of Q235 steel in simulated concrete pore solution (SCP) were systematically studied. The results demonstrated that the mixed BTA/SD showed an excellent anti-corrosion performance and the inhibition efficiency of (BTA/SD, 1ː1) was as large as 98.33 % which is higher than that of BTA (88.65 %) and SD (92.16 %). Furthermore, the synergistic inhibition effect of BTA/SD was also researched by surface analysis technologies, the X-ray photoelectron spectroscopy (XPS) result verified that the BTA/SD adsorbed on steel, while both scanning electron microscopy (SEM) and atomic force microscopy (AFM) images proved that the mixed BTA/SD can effectively protect the steel from corrosion in SCP solution which containing corrosive ions. In addition, the anti-corrosion mechanism of the mixed BTA and SD was revealed by adsorption model and molecular dynamics (MD) simulation, the mixed BTA/SD corrosion inhibitors showed the largest Kads, the lowest ∆Gads and the largest binding energy values, demonstrating the strong adsorption on steel and the best anti-corrosion performance. The results of this work can provide experimental and theoretical references for the corrosion protection of reinforced concrete structures while using synergistic inhibitors.