柠檬酸溶液中硫脲对碳钢的缓蚀作用和吸附热力学研究

Studis on Corrosion Inhibition and Adsorption Thermodynamics of Thiourea on Carbon Steel in Citric Acid

本文采用失重法考察了不同温度下3%柠檬酸中,不同浓度的硫脲对碳钢的缓蚀作用;并对柠檬酸介质中硫脲在碳钢表面吸附热力学进行了研究。硫脲低浓度时,随浓度增大,缓蚀作用增强;当其浓度达到一定值后,缓蚀作用基本保持不变。实验结果表明,硫脲在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律。ΔG^0<0,吸附过程自发进行;并且随着温度的升高ΔG^0增大,吸附作用降低。ΔH^0<0,表明反应是放热过程。ΔS^0<0,随着吸附过程的进行,体系进入更为有序状态。

The corrosion inhibition of thiourea on carbon steel in 3%citric acid was investigated with different temperatures and different concentration of thiourea by weight-loss method. And the adsorption thermodynamics of thiourea on the surface of carbon steel was investigated in citric acid. The corrosion inhibition of thiourea increases with the increase of concentrations of thiourea; when its concentration reaches a certain concentration, corrosion inhibition remains basically unchanged. The results show that thiourea on the surface of carbon steel produces a single molecule layer absorption and meets the Langmuir adsorption rule. △G^ 0〈 0 show that the adsorption process is spontaneous; AGO increases and adsorption reduces with the increase of temperature.△H^0〈 0 show that the reaction is exothermic chemical process. △S^0 〈0 show that the system turns into more orderly state with the process of adsorption.