Adsorption of mixed cationic-nonionic surfactant and its effect on bentonite structure  

作　　者：Yaxin Zhang Yan Zhao Yong Zhu Huayong Wu Hongtao Wang Wenjing Lu 

机构地区：[1]School of Environment,Tsinghua University,Beijing 100084,China [2]School of Environment,Beijing Normal University,Beijing 100875,China

出　　处：《Journal of Environmental Sciences》2012年第8期1525-1532,共8页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 40972151);the National HiTech Research and Development Program (863) of China(No. 2009AA064001)

摘　　要：The adsorption of cationic-nonionic mixed surfactant onto bentonite and its effect on bentonite structure were investigated. The objective was to improve the understanding of surfactant behavior on clay mineral for its possible use in remediation technologies of soil and groundwater contaminated by toxic organic compounds. The cationic surfactant used was hexadecylpyridinium bromide （HDPB）, and the nonionic surfactant was Triton X-100 （TXl00）. Adsorption of TXl00 was enhanced significantly by the addition of HDPB, but this enhancement decreased with an increase in the fraction of the cationic surfactant. Part of HDPB was replaced by TXl00 which decreased the adsorption of HDPB. However, the total adsorbed amount of the mixed surfactant was still increased substantially, indicating the synergistic effect between the cationic and nonionic surfactants. The surfaetant-modified bentonite was characterized by Brunauer-Emmett-Teller specific surface area measurement, Fourier transform infrared spectroscopy, and thermogravimetric-derivative thermogravimetric/differential thermal analyses. Surfactant intercalation was found to decrease the bentonite specific surface area, pore volume, and surface roughness and irregularities, as calculated by nitrogen adsorption-desorption isotherms. The co-adsorption of the cationic and nonionic surfactants increased the ordering conformation of the adsorbed surfactants on bentonite, but decreased the thermal stability of the organobentonite system.The adsorption of cationic-nonionic mixed surfactant onto bentonite and its effect on bentonite structure were investigated. The objective was to improve the understanding of surfactant behavior on clay mineral for its possible use in remediation technologies of soil and groundwater contaminated by toxic organic compounds. The cationic surfactant used was hexadecylpyridinium bromide （HDPB）, and the nonionic surfactant was Triton X-100 （TXl00）. Adsorption of TXl00 was enhanced significantly by the addition of HDPB, but this enhancement decreased with an increase in the fraction of the cationic surfactant. Part of HDPB was replaced by TXl00 which decreased the adsorption of HDPB. However, the total adsorbed amount of the mixed surfactant was still increased substantially, indicating the synergistic effect between the cationic and nonionic surfactants. The surfaetant-modified bentonite was characterized by Brunauer-Emmett-Teller specific surface area measurement, Fourier transform infrared spectroscopy, and thermogravimetric-derivative thermogravimetric/differential thermal analyses. Surfactant intercalation was found to decrease the bentonite specific surface area, pore volume, and surface roughness and irregularities, as calculated by nitrogen adsorption-desorption isotherms. The co-adsorption of the cationic and nonionic surfactants increased the ordering conformation of the adsorbed surfactants on bentonite, but decreased the thermal stability of the organobentonite system.

关 键 词：SURFACTANT BENTONITE surfactant modification ADSORPTION 

分 类 号：TQ423.2[化学工程] TQ423.12