酸性介质中菠菜提取物与KI对Q235钢的缓蚀性能

Corrosion Inhibition of Spinach Extract and KI on Q235 Steel in Acidic Medium

为了探明菠菜提取物与KI复配在0.5 mol/L H_(2)SO_(4)溶液中对Q235钢的协同缓蚀作用,利用失重法、电化学阻抗谱(EIS)、动电位极化曲线、扫描电镜(SEM)及能谱分析(EDS)探讨了0.5 mol/L H_(2)SO_(4)介质中菠菜提取物叶绿素(CHL)与KI对Q235钢材料的缓蚀协同作用及机理。结果表明:在0.5 mol/L H_(2)SO_(4)溶液体系中,CHL(100mg/L)与KI(50~200mg/L)复配时都表现出较好的缓蚀作用,缓蚀率都在90%以上,且当CHL与KI分别以100mg/L的浓度复配时,协同作用最好,缓蚀率高达98.04%。CHL与KI复配属于抑制阴极为主的混合型缓蚀剂。CHL及其与KI的复配物的缓蚀行为符合Langmuir等温吸附方程,为自发吸附过程,Q235钢表面形成了致密的保护膜。在0.5 mol/L H_(2)SO_(4)溶液体系中,CHL分子通过物理和化学吸附共同作用,吸附在Q235钢表面,阻止腐蚀反应发生。KI加入后,协助CHL分子吸附在Q235钢表面,提高了CHL分子的吸附率,表现为在降低腐蚀速率的同时,减少了CHL分子和KI的用量,增强了二者的协同效应进而提高了缓蚀率。

In order to explore the synergistic corrosion inhibition effect of spinach extract and KI on Q235 steel in 0.5 mol/L H_(2)SO_(4)solution,the synergistic corrosion inhibition effect and mechanism of spinach extract chlorophyll(CHL)and KI on Q235 steel in 0.5 mol/L H_(2)SO_(4)solution were studied by means of weight loss method,electrochemical impedance spectroscopy(EIS),potentiodynamic polarization curve,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).Results showed that when CHL(100 mg/L)and KI(50~200 mg/L)were combined in 0.5 mol/L H_(2)SO_(4)solution,the obtained compound always showed good corrosion inhibition with a corrosion inhibition rate above 90%.And when both CHL and KI were mixed with a concentration of 100 mg/L,the synergistic effect was the best,with a corrosion inhibition rate up to 98.04%.The compound of CHL and KI was a kind of mixed corrosion inhibitor that mainly inhibited the cathode.The corrosion inhibition behavior of CHL and its complex with KI conformed to Langmuir isothermal adsorption equation,which was a spontaneous adsorption process and formed a dense protective film on the surface of Q235 steel.In 0.5 mol/L H_(2)SO_(4)solution,CHL molecules were adsorbed on the surface of Q235 steel through physical and chemical adsorption to prevent corrosion reaction.The addition of KI could assist CHL molecules to adsorb on the surface of Q235 steel,improving the adsorption rate of CHL molecules.In this way,the corrosion rate as well as the amount of CHL and KI required for the inhibition were both reduced.Therefore,the synergistic effect of CHL and KI was enhanced and the inhibition efficiency was improved.