摘要
使用最大气泡法测定了十八烷基二甲基氯化铵 (C18DAC)水溶液的动态表面张力 ,考察了浓度、温度等对其DST的影响 ,详细表征了DST随时间的变化过程 ,计算了动态表面张力的各种参数 (n ,ti,t ,tm,R1/ 2 ) .结合Word Tordai方程计算了表观扩散系数 (Da)和吸附势垒 (Ea) ,对其吸附动力学模式进行了研究 ,探讨了DST参数的物理意义 .结果表明 ,t 值越小 ,吸附势垒Ea 越大 ,宏观扩散系数Da 越小 ,表面活性剂分子越不易吸附在溶液表面 ;C18DAC低浓度时吸附属于扩散控制模式 ,高浓度时属于混合控制模式 ;高浓度时 ,在吸附初期 (t→ 0 )为扩散控制模式 ,吸附后期 (t→∞ )为混合控制模式 .
The dynamic surface tension (DST) of octadecyl dimethylammonium chloride (C 18DAC) was measured using the maximum bubble pressure method. The effects of C 18DAC concentration and temperature on DST have been investigated systematically, and the parameters (n, t i, t *, t m, γ m, R 1/2) have also been calculated out. Combined with Word-Tordai equation, the effective diffusion coefficient D a and the adsorption barrier E a were obtained. The adsorption kinetics was studied and the physical meaning of DST parameters was also discussed. The results show that the smaller the t *, the smaller the effective diffusion coefficient D a, the bigger the adsorption barrier, and the more difficult for the surfactant to adsorb on the solution surface. The adsorption process is controlled by a diffusion step at low surfactant concentration or controlled by a mixed kinetic-diffusion adsorption mechanism at high surfactant concentration. When the concentration is high, the adsorption process is controlled by a diffusion step at the beginning; toward the end, it changes to a mixed kinetic-diffusion adsorption mechanism.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第4期669-673,共5页
Acta Chimica Sinica
基金
国家自然科学基金 (Nos.2 990 30 0 6
2 99730 2 3)
西南石油学院国家油气地质和开发重点实验室资助项目
