十二烷基硫酸钠在NaCl/NH_(4)Cl-C_(2)H_(5)OH-H_(2)O体系中的胶束化行为  

Micellar Behavior of Sodium Dodecyl Sulfate in NaCl/NH_(4)Cl-C_(2)H_(5)OH-H_(2)O Solution

作　　者：程文婷 翟颖 李倩倩 程芳琴 CHENG Wenting;ZHAI Ying;LI Qianqian;CHENG Fangqin(Institute of Resourees and Environental Engineering,Shanxi University,Taiyuan 030031,China)

机构地区：[1]山西大学资源与环境工程研究所,太原030031

出　　处：《高等学校化学学报》2025年第4期103-113,共11页Chemical Journal of Chinese Universities

基　　金：国家重点研发计划项目(批准号:2022YFC3901305);国家自然科学基金青年项目(批准号:22208198)资助。

摘　　要：在对NaCl和NH_(4)Cl型农药废盐的回收处理中,常采用表面活性剂十二烷基硫酸钠(SDS)胶束和乙醇对盐的结晶分离进行调控,因此研究SDS在废盐体系中的胶束化行为对实现此过程的精准调控至关重要.其中,SDS在废盐体系中的临界胶束浓度(CMC)是其胶束化行为的重要参数.本文在293.15~323.15 K温度范围内,采用表面张力法测定了SDS在Na Cl-H_(2)O,NH_(4)Cl-H_(2)O,NaCl-C_(2)H_(5)OH-H_(2)O和NH_(4)Cl-C_(2)H_(5)OH-H_(2)O_(4)种体系中的CMC,研究了温度、盐溶液浓度和乙醇的含量对SDS胶束行为的影响.结果表明,不添加乙醇时,在两种盐溶液中SDS的CMC值均随温度的升高而增大,而同一温度下SDS的CMC值随盐浓度的升高而减小;添加乙醇后,SDS在NH_(4)Cl溶液中的CMC值明显增大,而在NaCl溶液中呈先减小后增大的趋势.通过质量作用模型计算了SDS胶束化行为标准摩尔吉布斯自由能变■标准摩尔焓变■和标准摩尔熵变■3个标准热力学参数.由计算结果可知,SDS的胶束化行为均是自发进行且为放热过程.在NaCl-C_(2)H_(5)OH-H_(2)O体系中,乙醇的添加先促进后抑制SDS胶束的形成;而在NH_(4)Cl-C_(2)H_(5)OH-H_(2)O体系中,乙醇的添加始终抑制SDS胶束的形成.In the recycling treatment of NaCl and NH4Cl type pesticide waste salts,the crystalline separation of the salts is often regulated by the surfactant sodium dodecyl sulfate(SDS)micelles and ethanol,so the study of the micellization behaviour of SDS in the waste salt system is crucial to achieve the precise regulation of this process.Among them,the critical micelle concentration(CMC)of SDS in waste salt system is an important parameter for its micellization behaviour.The critical micellar concentration values of SDS in four systems,NaCl-H_(2)O,NH4Cl-H_(2)O,NaCl-C2H5OH-H_(2)O and NH4Cl-C2H5OH-H_(2)O,were determined using the surface tension method in the temperature range of 293.15—323.15 K.The effects of temperature,salt solution concentration and ethanol content on the micellar behavior of SDS were studied.The results showed that the CMC values of SDS in both salt solutions increased with the increase of temperature without adding ethanol,while the CMC values of SDS decreased with the increase of salt concentration at the same temperature.After the addition of ethanol,the CMC values of SDS in NH4Cl solution increased significantly,while it showed a tendency to decrease first and then increase in NaCl solution.Three standard thermodynamic parameters for the micellar behavior of SDS were calculated by mass action model:standard molar Gibbs free energy changes(ΔG 0 m),standard molar enthalpy change(ΔH 0 m)and standard molar entropy change(ΔS 0 m).From the calculation results,it is clear that the micellar behaviors of SDS are all spontaneous and exothermic.In the NaCl-C_(2)H_(5)OH-H_(2)O system,the addition of ethanol first promotes and then inhibits the formation of SDS micelles.While in the NH_(4)Cl-C_(2)H_(5)OH-H 2 O system,the addition of ethanol always inhibits the formation of SDS micelles.

关 键 词：十二烷基硫酸钠 临界胶束浓度 表面张力 热力学参数 

分 类 号：O648[理学—物理化学] TQ021.2[理学—化学]