Department of Environmental Science and Engineering, Xiangtan University, Xiangtan 411105, China.
J Hazard Mater. 2010 Jun 15;178(1-3):1078-84. doi: 10.1016/j.jhazmat.2010.02.050. Epub 2010 Feb 20.
The saturated level of cationic exchange capacity (CEC) of bentonite by organic cations can significantly influence the sorption capacity of the resulting organobentonites. In this work cationic polyacrylamide (CPAM) was applied to saturate part of the CEC of the cetyltrimethylammonium (CTMA) modified bentonite, with the aim to enhance their sorption capacity. XRD was applied to investigate the basal spacings of the organobentonites with and without CPAM, and the sorption characteristics of the organobentonites towards phenol and nitrobenzene to CTMA-bentonite was also studied. The XRD characterization results showed that the resulting organobentonites (C/P-Bt) had larger basal spacings than the CTMA modified bentonite (C-Bt), which indicated that both CPAM and CTMA could intercalate into the interlayer spaces of C/P-Bt. The saturated CEC of C/P-Bt increased with the intercalated amounts of CPAM. The sorption coefficients (K(d)) of phenol and nitrobenzene on C/P-Bt were shown to first increase with the saturated CEC until the maximum, and then began to decrease as the saturated CEC further increased. The maximum increase of K(d) reached 41% and 23% for phenol and nitrobenzene, respectively, which could be ascribed to the enhanced affinity of the adsorbed CTMA aggregates towards the sorbates. Results of this work showed that the simultaneous intercalation of CPAM could be a novel method to enhance the sorption capacity of the traditional organobentonites.
有机阳离子对膨润土的阳离子交换容量（CEC）的饱和水平会显著影响所得有机膨润土的吸附能力。在这项工作中，应用阳离子聚丙烯酰胺（CPAM）来饱和部分 CTMA 改性膨润土的 CEC，以提高其吸附能力。XRD 被用于研究有机膨润土的层间距，包括含有 CPAM 和不含有 CPAM 的有机膨润土，并研究了有机膨润土对苯酚和硝基苯的吸附特性。XRD 特征化结果表明，所得有机膨润土（C/P-Bt）具有比 CTMA 改性膨润土（C-Bt）更大的层间距，这表明 CPAM 和 CTMA 都可以插入 C/P-Bt 的层间空间。C/P-Bt 的饱和 CEC 随着 CPAM 的插入量的增加而增加。C/P-Bt 对苯酚和硝基苯的吸附系数（K(d)）表现出随着饱和 CEC 的增加先增加，直到达到最大值，然后随着饱和 CEC 的进一步增加而开始降低。对于苯酚和硝基苯，K(d)的最大增加分别达到了 41%和 23%，这可以归因于吸附的 CTMA 聚集体对吸附质的亲和力增强。这项工作的结果表明，CPAM 的同时插入可能是增强传统有机膨润土吸附能力的一种新方法。
