硫酸溶液中[双(4-甲氧基苯基)]二硫代磷酸二乙铵对碳钢的缓蚀性能研究

Study on Corrosion Inhibition of Diethylammonium Di (4-methoxyphenyl) Dithiophosphate for Carbon Steel in Sulfuric Acid Solution

合成了[双(4-甲氧基苯基)]二硫代磷酸二乙铵(DEDP),然后采用电化学法与失重法研究了DEDP作为新型缓蚀剂于硫酸溶液中对碳钢的缓蚀性能。研究结果表明:DEDP是一种抑制阳极反应为主的混合型缓蚀剂,在碳钢表面的吸附符合Langmuir吸附等温式,吸附自由能为-34.00 k J·mol-1,其吸附为自发进行的物理和化学吸附;同时,考察缓蚀性能的各影响因素发现,随DEDP浓度增加缓蚀率升高,相反随腐蚀体系温度升高、硫酸浓度增大和缓蚀液存储时间延长缓蚀率均下降;300 K条件下1.0MH_2SO_4溶液中DEDP浓度160 mg·L^(-1)时缓蚀率高于94%。

Diethylammonium di （4-methoxyphenyl）dithiophosphate （DEDP） was synthesized as a new corrosion inhibi- tor. The corrosion inhibition of DEDP for carbon steel in sulfuric acid solution was evaluated by using weight loss method and electrochemistry method. The result shows that DEDP is a mixed type inhibitor which mainly suppressed the anodic reaction. Meanwhile, the adsorption of the inhibitor on carbon steel surface obeys Langmuir adsorption isotherm, which belongs to spontaneous chemical and physieal adsorption. The adsorption free energy is -34. 00 kJ· mol. In addition, by investigating of various influencing factors of eorrosion inhibition it is discovered that the inhibition efficiency increased with the increasing of DEDP concentration, and on the contrary decreased respectively with the increasing of sulfuric acid concentration, corrosion system temperature and inhibited solution storage time. The inhibition efficiency of DEDP （160 mg· L^-l） for carbon steel in l. 0 M H2SO4 at 300 K exceeded 94%.