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目的 研究芭蕉叶提取物( MBLE)在酸性环境中对碳钢腐蚀的抑制行为. 方法 通过热水浸提法获取MBLE,采用电化学方法研究在不同实验温度和不同浓度下MBLE在1 mol/L盐酸溶液中对碳钢的缓蚀行为,并用扫描电镜( SEM)研究金属表面腐蚀形貌. 结果 极化曲线研究表明,MBLE对碳钢在1 mol/L盐酸中的腐蚀有明显抑制作用,属阴极抑制为主的混合型缓蚀剂;其缓蚀性能随质量浓度增大而增强,25 ℃时160 mg/L的MBLE缓蚀效率达到94 . 7 %. 电化学阻抗图谱研究表明,随着MBLE质量浓度的增大,碳钢表面腐蚀反应的电荷转移电阻逐渐增大,腐蚀反应抑制程度增强. 变温试验研究表明, MBLE在实验温度范围内具有较好的稳定性. 当MBLE质量浓度为160 mg/L时,温度从25 ℃增加到40℃,两种电化学方法所得缓蚀效率的变化幅度均在3%以内. MBLE缓蚀剂分子在碳钢表面的吸附服从Dhar-Flory-Huggins等温吸附式,并且属于物理和化学混合吸附. SEM研究表明,盐酸介质中MBLE可有效地抑制碳钢的腐蚀. 结论 对碳钢在盐酸介质中的腐蚀,MBLE是有效的绿色缓蚀剂.

Objective To investigate the inhibitive action of extracts of Musa basjoo leaves ( MBLE) on the corrosion of carbon steel in acidic medium. Methods MBLE was achieved by hot water extraction method, and its inhibition effect on the carbon steel corrosion in 1 mol/L HCl solution at different temperatures and extract concentrations was investigated by electrochemical methods.The surface morphology of the carbon steel was examined by scanning electron microscopy ( SEM) both in the absence of an inhibi-tor and in the presence of a MBLE-containing corrosive medium. Results The obtained results of polarization curves indicated that MBLE acted as a mixed-type inhibitor with a preferential effect on cathodic reaction for steel corrosion in 1 mol/L HCl solution. The inhibition efficiency was found to increase with increasing MBLE concentration and reached up to maximum 94. 7 % at the MBLE concentration of 160 mg/L at 25℃. The analysis of electrochemical impedance spectroscopy implied that the charge transfer resistance of surface corrosion reaction increased with increasing MBLE concentration, which could lead to more effective suppres-sion of the corrosion reaction. Changing-temperature measurements indicated that the inhibition of MBLE had a preferable thermal stability within the range of experiment temperature. When the temperature increased from 25 ℃ to 40 ℃, the variations of inhibi-tion efficiency obtained by the two electrochemical methods at MBLE concentration of 160 mg/L were less than 3%. The adsorption of MBLE molecules on the steel surface obeyed the Dhar-Flory-Huggins adsorption isotherm and was a spontaneous adsorption process including both physisorption and chemisorption. The SEM observations showed that MBLE could effectively inhibit steel corrosion. Conclusion MBLE is an effective and environmentally friendly inhibitor for carbon steel in HCl medium.