薄荷叶多糖作为碳钢酸洗缓蚀剂的研究  

Study on inhibition performance of extracted polysaccharides from mint leaves for pickling of carbon steel

作　　者：田子诚 李国楼 周晓荣 王丹 韩娟娟 任占冬 Tian Zicheng;Li Guolou;Zhou Xiaorong;Wang Dan;Han Juanjuan;Ren Zhandong(School of Chemical and Environmental Engineering,WuHan Polytechnic University,Wuhan 430023,China)

机构地区：[1]武汉轻工大学化学与环境工程学院,湖北武汉430023

出　　处：《电镀与精饰》2024年第6期34-41,共8页Plating & Finishing

基　　金：2023年校立大学生科研项目;湖北省自然科学基金项目(2020CFB777)。

摘　　要：以水作为提取剂,以乙醇为沉淀剂,从薄荷叶中提取并分离出多糖类物质(EPM),作为碳钢酸洗缓蚀剂。在2 mol·L^(-1) HCl水溶液中,采用失重法测试了20~60 ℃范围内EPM对碳钢的缓蚀性能。研究表明:EPM对碳钢在2 mol·L^(-1) HCl水溶液中的腐蚀有一定的抑制作用,随着EPM浓度的增大,缓蚀效率增大,当浓度达到320 mg·L^(-1)以后,缓蚀效率基本保持不变。当温度为20 ℃、EPM浓度为400 mg·L^(-1)时,缓蚀效率达到最高,为89.45%。随着酸洗温度的升高,EPM的缓蚀效率降低。当温度为60 ℃、EPM的浓度为400 mg·L^(-1)时,缓蚀效率降低为49.39%。通过热力学和动力学综合分析可知,EPM的缓蚀作用归因于在碳钢表面形成单分子吸附层,服从Langmuir吸附模型,为物理吸附和化学吸附共存的放热过程,EPM吸附层增加了碳钢在HCl水溶液中的腐蚀反应的表观活化能(Ea)。将EPM和未分离多糖的薄荷叶总提取物(EM)对碳钢的缓蚀作用进行比较研究,发现在常温下使用时EPM的缓蚀性能优于EM,当腐蚀温度达到40 ℃以上时,EPM的缓蚀性能下降,低于EM。Polysaccharide(EPM)was extracted and separated from mint leaves using water as extractant and ethanol as precipitator,which was used as corrosion inhibitor for pickling of carbon steel.The corrosion inhibition performance of EPM on carbon steel was tested using weight loss method in 2 mol·L^(-1) HCl aqueous solution at temperature range of 20-60℃.The results showed that EPM had a certain inhibitory effect on the corrosion of carbon steel in 2 mol·L^(-1) HCl aqueous solution.With the increase of EPM concentration,the corrosion inhibition efficiency increased.The inhibition efficiency was relatively stable when the concentration of EPM reached 320 mg·L^(-1).The maximum efficiency was 89.45% when the temperature was 20℃ and EPM concentration was 400 mg·L^(-1).The corrosion inhibition efficiency of EPM decreased with the increase of pickling temperature.The inhibition efficiency decreased to 49.39% when the temperature was 60℃ and EPM concentration was 400 mg·L^(-1).According to the comprehensive analysis of thermodynamics and kinetics,the inhibition effect of EPM was attributed to the formation of a single molecular adsorption layer on the surface of carbon steel,which followed the Langmuir adsorption model.It was an exothermic process with the coexistence of physical adsorption and chemical adsorption.The apparent activation energy(Ea)of the corrosion process of carbon steel with EPM in HCl aqueous solution was increased.The inhibition effect of EPM and the extract of mint leaves(EM)on carbon steel were compared.It was found that the inhibition performance of EPM was better than that of EM at room temperature.When the corrosion temperature was above 40℃,the inhibition performance of EPM decreased and was lower than that of EM.

关 键 词：薄荷叶提取物 多糖 缓蚀剂 失重法 

分 类 号：TG174.42[金属学及工艺—金属表面处理]