The effect of CTAB on Na_2SO_4 nucleation in mixed Na_2SO_4/CTAB aerosols by FTIR-ATR technology  

作　　者：Dan-Ting Tan Xu Shao Shu-Feng Pang Yun-Hong Zhang 

机构地区：[1]The Institute of Chemical Physics, School of Chemistry, Beijing Institute of Technology

出　　处：《Chinese Chemical Letters》2016年第7期1073-1076,共4页中国化学快报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 21373026, 21473009.)

摘　　要：FTIR-ATR technology is used to study the efflorescence kinetic of Na2SO4 and mixed Na2SO4/CTAB aerosols.As the RH decreased linearly,the v3-SO42 band shifts from 1094 cm1 to 1132 cm1,suggesting the phase transition of Na2SO4 from solution to crystal phase（Ⅲ）.For pure Na2SO4 aerosols,the ERH is 75.1%RH,whereas the efflorescence point of mixed Na2SO4/CTAB aerosols（74.2%） is lower.By further analysis of IR differential spectra,the ratio of Na2SO4 crystals in mixed aerosols is only 62.7%and the heterogeneous nucleation rate of Na2SO4 in Na2SO4/CTAB mixed aerosols is lower than that in pure Na2SO4 aerosols.They showed that CTAB assembled into reversed micelle and part Na2SO4 droplets are in the core to form core-shell structure,and CTAB shell prevents core Na2SO4 solutions from crystallizing.However,the counter ion Br for CTAB reversed micelle can interact with Na＋ ions,which decreases the crystallization rate of free Na2SO4 droplets and ERH is delayed.FTIR-ATR technology is used to study the efflorescence kinetic of Na2SO4 and mixed Na2SO4/CTAB aerosols.As the RH decreased linearly,the v3-SO42 band shifts from 1094 cm1 to 1132 cm1,suggesting the phase transition of Na2SO4 from solution to crystal phase（Ⅲ）.For pure Na2SO4 aerosols,the ERH is 75.1%RH,whereas the efflorescence point of mixed Na2SO4/CTAB aerosols（74.2%） is lower.By further analysis of IR differential spectra,the ratio of Na2SO4 crystals in mixed aerosols is only 62.7%and the heterogeneous nucleation rate of Na2SO4 in Na2SO4/CTAB mixed aerosols is lower than that in pure Na2SO4 aerosols.They showed that CTAB assembled into reversed micelle and part Na2SO4 droplets are in the core to form core-shell structure,and CTAB shell prevents core Na2SO4 solutions from crystallizing.However,the counter ion Br for CTAB reversed micelle can interact with Na＋ ions,which decreases the crystallization rate of free Na2SO4 droplets and ERH is delayed.

关 键 词：FTIR-ATR Na2SO4/CTAB EFFLORESCENCE Nucleation rate RH 

分 类 号：O648.18[理学—物理化学]