酸化介质中几种氨基酸的缓蚀性能及缓蚀机理

Inhibition Performance and Mechanism of Several Amino Acids in Acidic Media

采用失重法、电化学方法研究了5种氨基酸在酸化介质中对A3钢片的缓蚀性能及缓蚀机理。结果表明,在30℃时,五种氨基酸对A3钢的缓蚀效率均随盐酸浓度的增加而减小。半胱氨酸对2%的盐酸中A3钢的缓蚀效率随温度的升高而增大,其余氨基酸的缓蚀效率均随温度的升高而下降;半胱氨酸对A3钢的缓蚀效率随加量的增加而下降,而其余四种氨基酸的缓蚀效率均随加量的增加而升高;在2%的盐酸中,氨基酸加量为200mg/L时,五种氨基酸对A3钢片的缓蚀效率依次为半胱氨酸>酪氨酸>组氨酸>精氨酸>亮氨酸;通过正交试验确定了半胱氨酸对A3钢在盐酸中的最佳缓蚀条件。缓蚀机理探讨表明,五种氨基酸均为阴极抑制型缓蚀剂;亮氨酸和酪氨酸在A3钢片表面的吸附基本服从Frumkin等温线,而半胱氨酸、精氨酸和组氨酸的吸附不服从该等温线。

The inhibition performance and mechanism of five amino acids as inhibitors for steel were studied in acidic media by weight loss method and electrochemical method.The results showed that the inhibition efficiency of these amino acids for A3 steel decreased with increasing the concentration of HCl at 30 ℃.The inhibition efficiency of cysteine for A3 steel in 2% HCl increased with the rise of the temperature while that of other amino acids decreased.To A3 steel,the inhibition efficiency of cysteine decreased with increasing the dosage of the amino acids while that of others increased.When the dosage of amino acids was 200 mg/L,the order of inhibition efficiency to A3 steel of these five kinds of amino acids was cysteine histidine tyrosine arginine leucine in 2% HCl.The optimal inhibiting condition of cysteine to A3 steel in HCl was confirmed through an orthogonal test.The results of the corrosion inhibition mechanism study show that all of these amino acids are cathodic inhibitors and the adsorption of leucine and histidine on A3 steel obeys the Frumkin equation while the adsorption of other amino acids do not obey it.