缓蚀剂应用于碳化混凝土再碱化技术的可行性研究

Feasibility Study of Application of Corrosion Inhibitor to Realkalization for Carbonated Concrete

通过量子化学计算、分子动力学模拟和电化学测试对阳离子型醇胺缓蚀剂在模拟混凝土孔隙液中对Q235钢的缓蚀机理与性能进行了研究.结果表明:醇胺类分子最高占有轨道位于N原子周围,最低未占轨道位于O原子周围,这种分布可使缓蚀剂在金属表面形成多中心吸附,使缓蚀剂分子在金属表面的吸附更加稳定;4种物质的缓蚀率大小为:N,N-二甲基乙醇胺>二乙醇胺>正丙醇胺>乙醇胺,且计算结果与试验结果一致.在等温等压下,N,N-二甲基乙醇胺、二乙醇胺、正丙醇胺与乙醇胺都能自发地吸附在钢筋表面,其ΔG0分别为-22.256,-23.644,-20.920,-18.910kJ/mol,为单分子层物理吸附.

The inhibition mechanism and performance of the alcohol-amine corrosion inhibitor for the Q235 steel in the simulated pore solution of the concrete were studied by quantum chemistry calculation, molecu- lar dynamic simulation and electrochemical test. Through the analysis of frontier orbital, the highest occu- pied molecular orbital（HOMO） of the alcohol-amine molecules locates near the N atom and the lowest un- occupied molecular orbital（LUMO） is around the O atom. This distribution can make the corrosion inhibi- tor to form multi-adsorption center on the metal surface and make the adsorption more stable. By analyzing the global database and molecular dynamic of the four kinds of molecular, the inhibition rate is N, N-dime- thyl ethanolamine〉diethanolamine〉 propylamine〉 ethanolamine. The parameters that were obtained from electrochemical impedance spectroscopy（EIS） indicate that the inhibition rate is N, N-dimethyl etha- nolamine〉diethanolamine〉 propytamine〉 ethanolamine. This is consistent with the result obtained from quantum chemistry calculations. The alcohol-amine molecules can spontaneously adsorb on the steel sur- face. The ΔG0 is about -20 kJ/mol, the mechanism of the adsorption is physisorption.