表面活性剂的吸附对在水中氧化铝微粉悬浮体稳定性的影响

The Effect of Adsorption of Surfactants on Stability of Suspension of Alumina Powders

测定了氧化铝微粉自不同ｐＨ的水溶液中吸附十二烷基苯磺酸钠（ＳＤＢＳ）、氯化十四烷基吡啶（ＴＰＣ）和ＴｒｉｔｏｎＸ－１００（ＴＸ－１００）的吸附等温线及相应的电动电势ζ变化曲线。研究了氧化铝微粉在这些表面活性剂水溶液中的悬浮稳定性。结果表明：（１）在适宜ｐＨ时ＳＤＢＳ和ＴＰＣ的吸附等温线为双平台（ＬＳ）型，达最大吸附量时吸附分子近于单层紧密排列；在表面活性剂浓度很低时氧化铝粒子带电符号即发生变化，随浓度增加ζ电势急剧增加直至趋于恒定值；在水中悬浮体的稳定性主要由粒子表面电性质和吸附分子的取向决定，等电点处稳定性最低，ζ电势增加和吸附分子亲水基朝向水相都使悬浮体稳定性增加。

The adsorption of sodium dodecyl sulfonate (SDBS),tetradecyl pyridine chloride (TPC) and Triton X 100 (TX 100) onto the alumina powders at various pH was studied.The ζ potential of the particles and the stability of the suspension in water were determined.The main results are as follows. (1) At suitable pH,the adsorption isotherms are LS type for SDBS and TPC.At higher concentration of surfactants,association on the surface occurs to form a close packed monolayer.The orientation of hydrophilic group to water phase was inferred from values of adsorption limit,surface area and molecular dimensions.The sign of ζ potential of alumina powder was opposite to the original one in lower concentration of SDBS or TPC,and the values of ζ potential increased with increasing concentration.The stability of suspension of alumina powders is a function of SDBS or TPC concentration and displays an V shaped curve with increasing concentration at lower concentration.(2) At pH 6.9 and higher concentration,monolayer on the surface of alumina was formed by adsorption of TX 100.In the monolayer the hydrophilic EO group interact with the hydroxy of surface and the hydrophilic group is in water phase.Then the stability of the suspension of alumina powders is lower than that of the suspension at lower concentration of TX 100.