O,O'-二(2-苯乙基)二硫代磷酸二乙铵在HCl溶液中对Q235钢的缓蚀性研究

合成了一种新型缓蚀剂O,O'-二(2-苯乙基)二硫代磷酸二乙铵(EPP),并用元素分析和红外光谱对其进行了表征。采用静态失重法、极化曲线法和电化学阻抗法研究了EPP在HCl溶液中对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为,考察了HCl浓度、腐蚀体系温度等因素对其缓蚀率的影响。结果表明:EPP是一种高效的混合型缓蚀剂,其缓蚀率随缓蚀剂浓度增加而增大,随腐蚀系统温度升高而缓慢减小。在30℃,1.0 mol·L-1的HCl溶液中,EPP浓度为60 mg·L-1时,其缓蚀率高达98.48%。EPP在Q235钢表面的吸附符合Langmuir吸附等温式,属于自发进行的化学吸附。量子化学计算结果表明,EPP通过配位键和反馈键与金属Fe形成了多中心、稳定的化学吸附。

Corrosion Inhibition Performance of Diethylammonium O,O '-Di(2-phenylethyl)dithiophosphate for Q235 Steel in HCl Solution

A new corrosion inhibitor, diethylammonium O,O '-di(2-phenylethyl)dithiophosphate (EPP), was synthesized and characterized by elemental analysis and IR spectrum. Its inhibitive effect, adsorption behavior, and influence factors for Q235 steel in HCl solution were evaluated by weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results showed that EPP was a mixed type inhibitor, the inhibitive efficiency increased gradually with the increase of inhibitor concentration, but decreased slowly with temperature of corrosion system. The inhibitive efficiency was up to 98.48% at the inhibitor concentration of 60 mgL^-1 in 1.0 molL^-1 HCl at 30 ℃. The adsorption of EPP on Q235 steel surface was consistent with the Langmuir adsorption isotherm and belonged to chemisorptions. The quantum chemical calculations showed that the coordination bond and back-donating bond could be easily formed between inhibitor molecules and metal Fe atoms, and thereby the multicenter, stable chemical adsorption could be formed.