土酸溶液中苯扎氯铵对不锈钢的缓蚀作用及吸附热力学研究

Corrosion inhibition and adsorption thermodynamics of benzalkonium chloride for stainless steel in mud acid solution

为了研究土酸介质中烷基季铵盐类阳离子表面活性剂对不锈钢的缓蚀及吸附作用,采用静态失重法在不同温度的10%土酸溶液中苯扎氯铵对304#不锈钢的缓蚀作用,应用吸附理论和Sekine方法对静态挂片试验数据进行处理.结果表明,苯扎氯铵在不锈钢表面的定向吸附是产生缓蚀的主要原因,当其含量达到一定浓度后,缓蚀作用基本保持不变;在浓度为0～0.2%时,其在不锈钢表面的吸附服从Langmuir吸附等温式,相关系数大于0.99;缓蚀率随浓度的增加和温度的升高而增大,是由吸附过程中表现为总熵增加的特点决定的;获得了吸附过程△H°、△S°和△G°等重要热力学参数.

In order to study the alkyl quaternary ammonium salt cationic surfactant＇s corrosion inhibition and adsorption for the stainless steel in the mud acid, the corrosion inhibition of benzalkonium chloride on 304# stainless steel in different temperature, 10% mud acid was investigated by static weight-loss method. The experimental data were treated by using the adsorption theory and the Sekine method to the static state. The result showes that the directional adsorption for the stainless steel is the key of the corrosion inhibition. After its content achieved the certain concentration, the corrosion inhibition is in gross invariable. The benzalkonium chloride＇s adsorption on the stainless steel obeys basically Langmuir＇s isotherm in 0 ～0.2% concentration, and the correlation coefficient is more than 0.99. The corrosion inhibition efficiency is increased with concentration increasing and temperature rising, It was decided by the total entropy＇s increases in the adsorption process. Some important thermodynamic parameters such as ΔH°, ΔS° and ΔG° in adsorption process were obtained.