摘要
以膨润土(BT)为基质,采用共沉淀法制备负载Fe3O4的磁性膨润土(MBT),在两性表面活性剂十二烷基二甲基甜菜碱(BS-12)修饰(BS-MBT)的基础上,以阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)/阴离子表面活性剂十二烷基磺酸钠(SDS)为复配修饰剂,通过湿法分别制备2种两性复配修饰磁性膨润土(BS-CT-MBT/BS-SDS-MBT),采用扫描电镜、X-射线衍射、热重、红外光谱对样品进行表征,测定磁性、比表面积和孔容等性质,通过批处理实验法对比两性复配修饰磁性膨润土对苯酚的吸附.结果表明,两性复配修饰膨润土具有良好的磁分离性能.与BS-MBT相比,BS-CT-MBT的C、N质量分数增大,复配修饰剂质量分数增加,孔容和比表面积减小,BS-SDS-MBT的C、N质量分数减小,复配修饰剂质量分数减少,孔容减小,比表面积增大.在pH 6.0的0.1 mol·L^(-1)Na Cl溶液中各修饰剂的解吸率低于9%.各土样对苯酚的等温吸附数据符合Henry模型,以分配吸附为主,吸附量顺序为BS-CT-MBT>BS-MBT>BS-SDS-MBT>BT>MBT,修饰剂质量分数是影响苯酚吸附的决定性因素,CTMAB提升土样吸附苯酚能力的效果高于SDS.
Magnetic bentonite is modified by an amphoteric surfactant(dodecyl dimethyl betaine,BS-12),then modified by a cationic surfactant(Cetyl Trimethyl Ammonium Bromide,CTMAB) and anionic surfactant(Sodium lauryl sulfonate,SDS).Amphotericcationic modified magnetic bentonite(BS-CT-MBT) and amphoteric-anionic modified magnetic bentonite(BS-SDS-MBT) are obtained.Structural identification of the samples were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),thermogravimetric analyses(TG),Fourier transform infrared spectra(FTIR),and vibrating sample magnetometer(VSM).The carbon-nitrogen content,specific surface area,and pore volume were also evaluated.Batch isotherm studies were conducted to evaluate the sorption of phenol.The results show that BS-CT-MBT and BS-SDS-MBT can be separated by magnetic separation.The carbon content-nitrogen content and content of surfactants of the BS-CT-MBT increase,while surface area and pore volume decrease compared to those of BS-MBT.Compared with BS-MBT,the carbon-nitrogen content,content of surfactants,and pore volume of BSSDS-MBT are decreasing and surface area is increasing.The desorption rate of the surfactants is less than 9% at pH 6.0 and in 0.1 mol·L^-1 Na Cl solution.The Henry equation is the optimal description for the phenol sorption isotherms,implying a partitioning sorption process.The amount of phenol sorption follows the order:BS-CT-MBT〉BS-MBT〉BS-SDS-MBT〉BT〉MBT,which significantly correlates with the variation of the content of surfactant.Amphoteric magnetic bentonites modified by CTMAB have better absorption performance for phenol than those modified by SDS.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第1期187-194,共8页
Environmental Science
基金
国家自然科学基金项目(41271244)
陕西省重点研发计划项目(2017SF-385)
关键词
磁性
膨润土
表面活性剂
表面特征
苯酚
吸附
magnetic
bentonite
surfactant
characterization
phenol
sorption