| 阳(阴)离子复配修饰两性磁性膨润土的表面特征差异及对苯酚吸附的影响 |
| 摘要点击 3453 全文点击 1167 投稿时间：2017-06-22 修订日期：2017-07-25 |
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| 中文关键词 磁性 膨润土 表面活性剂 表面特征 苯酚 吸附 |
| 英文关键词 magnetic bentonite surfactant characterization phenol sorption |
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| 中文摘要 |
| 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 NaCl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. |
| 英文摘要 |
| 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). Amphoteric-cationic 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 BS-SDS-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 NaCl 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. |
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