采用二氧化氯消毒水时添加咪唑基离子液体对黄铜缓蚀作用的研究

Corrosion inhibition of brass by adding imidazolium-based ionic liquid during water disinfection with chlorine dioxide

[目的]采用二氧化氯(ClO_(2))对水进行消毒时常常面临黄铜件腐蚀问题,寻找适宜的缓蚀剂具有重要意义。[方法]通过静态挂片试验、动电位极化曲线测试、腐蚀形貌观察及产物成分分析,研究了在ClO_(2)溶液中添加1-丁基-3-甲基咪唑乙酸盐(BMIMAc)或1-丁基-3-甲基咪唑溴盐(BMIMBr)对H62黄铜的缓蚀效果,并通过密度泛函理论(DFT)计算及分子动力学(MD)模拟探讨了两种咪唑基离子液体对黄铜的缓蚀机理。[结果]在ClO_(2)溶液中添加BMIMAc或BMIMBr都能够在一定程度上抑制黄铜的腐蚀,并且缓蚀效率随着BMIMAc或BMIMBr浓度的增大而升高,BMIMAc的缓蚀效果优于BMIMBr。BMIMAc和BMIMBr都属于抑制阴极反应的阴极缓蚀剂,二者在黄铜表面的吸附都遵循Langmuir等温模型。BMIMAc和BMIMBr都能够以平行排列的方式吸附在黄铜表面,生成阻止黄铜与腐蚀溶液接触的吸附膜,从而减缓腐蚀。[结论]在采用ClO_(2)消毒水的过程中添加适量BMIMAc或BMIMBr都能够对黄铜起到有效的缓蚀作用。

[Introduction]The brass parts are often confronted with corrosion problem during water disinfection with chlorine dioxide(ClO_(2)),so it is important to find suitable corrosion inhibitors.[Method]The corrosion inhibition efficiency by adding 1-butyl-3-methylimidazole acetate(BMIMAc)or 1-butyl-3-methylimidazole bromide(BMIMBr)to ClO_(2)solution on the corrosion inhibition of H62 brass was studied by static hanging test,potentiodynamic polarization measurement,corrosion morphology observation,and corrosion product composition analysis.The corrosion inhibition mechanisms of the two kinds of imidazolium-based ionic liquids on brass were discussed by density functional theory(DFT)calculation and molecular dynamics(MD)simulation.[Result]The addition of either BMIMAc or BMIMBr to ClO_(2)solution could inhibit the corrosion of brass to a certain extent,and the corrosion inhibition effectiveness was increased with the increasing of BMIMAc or BMIMBr concentration.BMIMAc showed better inhibition efficiency on brass than BMIMBr.Both BMIMAc and BMIMBr are cathodic corrosion inhibitors that inhibit cathodic reactions,and their adsorption onto brass surface followed the Langmuir isothermal model.Both BMIMAc and BMIMBr are capable of adsorbing onto brass surface in a parallel arrangement,forming an adsorbent film that can prevent brass from contraction with corrosive media,and slowing down the corrosion of brass further.[Conclusion]The corrosion of brass can be effectively inhibited during water disinfection by adding an appropriate amount of BMIMAc or BMIMBr to ClO_(2) solution.