一种环保型缓蚀剂利拉利汀对紫铜在硫酸中的缓蚀机理研究

Corrosion Inhibition Mechanism of the Eco-friendly Corrosion Inhibitor Linagliptin on Copper in Sulfuric Acid

使用电化学阻抗技术、失重法等研究了一种被用于治疗人类糖尿病且价格低廉的利拉利汀(LNLP)药物在0.5 mol/L硫酸溶液中对Cu的缓蚀作用和缓蚀机理。结果表明,LNLP能够有效抑制Cu在硫酸中的腐蚀,是一种绿色环保型缓蚀剂。电化学阻抗测试显示该物质能够增大Cu表面的膜电阻和电荷转移电阻,降低膜电容和双电层电容来减缓Cu在0.5 mol/L硫酸溶液中的腐蚀速率。当LNLP浓度仅为1 mmol/L时,其缓蚀效率高达99.95%。动电位极化曲线测试结果表明,LNLP是一种谦逊的混合型缓蚀剂,能够有效地抑制Cu表面的阴阳极反应。利用吸附等温曲线和理论计算探究了LNLP与Cu表面的相互作用和LNLP分子结构与缓蚀性能之间的构效关系。结果表明,LNLP在Cu表面的吸附是一种平行吸附形态,最大程度地为Cu提供了保护。LNLP分子在Cu表面的吸附主要是以分子内的氮、氧杂原子和共轭的环状官能团为活性吸附中心,通过物理和化学吸附的协同作用,在Cu表面形成了单分子层膜,隔绝了腐蚀介质与Cu表面的接触。

Developing high-efficiency and eco-friendly corrosion inhibitors to replace traditional toxic and harmful ones is necessary to protect the ecological environment.Based on these premises,we employed electrochemical impedance techniques,gravimetric methods,and others to investigate the corrosion inhibition and mechanism of a low-cost drug,liraglutide(LNLP),used for human diabetes treatment,on copper in 0.5 mol/L sulfuric acid solution.The findings demonstrate that LNLP is a green,eco-friendly type of corrosion inhibitor,and is effective in inhibiting the corrosion of copper in sulfuric acid.The electrochemical results show that LNLP could slow down the corrosion rate of copper in 0.5 mol/L H2SO4 solution by increasing the film and charge transfer resistance and reducing the film and double-layer capacitance.When the concentration of LNLP is only 1 mmol/L,theηis as high as 99.95%.Potentiodynamic polarization curves results indicate that LNLP is a modest mixed-type inhibitor that can inhibit the anodic and cathodic reactions of copper.Based on the adsorption curve and theoretical calculation,the interaction between LNLP and the copper surface and the structure-performance relationship of LNLP molecule are revealed.The relevant results show that the adsorption of LNLP on the copper surface is parallel,providing max protection for copper.The adsorption of LNLP molecules on the copper is mainly through the nitrogen,oxygen heteroatoms,and conjugated ringy functional groups within the molecules,forming a single-molecule film through the synergistic effect of physical and chemical adsorption,isolating corrosive media from the copper surface.