CTAB改性磁性膨润土对刚果红和酸性大红的吸附

Adsorption of Congo Red and Acidic Red by magnetic bentonite modified with CTAB

为提高膨润土的固液分离能力及其对难降解污染物的吸附效果,采用十六烷基三甲基溴化铵(hexadecyltrimethyl ammonium bromide,CTAB)对磁性膨润土(magnetic bentonite,MB)进行有机改性,制得 CTAB 改性磁性膨润土(MB modified by CTAB,CTAB/MB),考察 CTAB/MB 吸附刚果红(Congo Red,CR)和酸性大红(Acidic Red,AR)的性能,并进行吸附机理研究。研究结果表明, CTAB/MB 为多级孔结构材料,具有良好的磁分离和磁稳定性能;CTAB/MB对 50 mg L 1 CR 和 AR 的吸附平衡时间分别为 30 和 90 min,而 MB 对 CR 和 AR 的吸附平衡时间则分别为 5 和 3 h;在 pH 4~11 时,CTAB/MB 对 CR 和 AR 的去除率均保持在 85%以上;5 次循环利用后,CTAB/MB 对 CR 和 AR 的吸附保持在 90%和 92%以上;CTAB/MB 对染料的吸附符合 Langmuir 模型和准二级吸附动力学模型;CTAB/MB 吸附CR 和 AR 的机理主要包括离子交换、静电吸引和表面吸附。总之,CTAB/MB 是一种具有良好应用前景的染料废水吸附材料。

Magnetic bentonite (MB) was modified by hexadecyl trimethyl ammonium bromide (CTAB) to obtain CTAB modified magnetic bentonite (CTAB/MB) for the improvement of its solid-liquid separation performance and adsorption of bentonite refractory pollutants. The adsorption performance and mechanism of Congo Red (CR) and Acidic Red (AR) on CTAB/MB were investigated. The results indicate that CTAB/MB exhibits multistage porous material characteristics and good magnetic separation ability and stability. CR and AR (50 mg L 1) adsorption on CTAB/MB reached equilibrium within 30 and 90 min, respectively, which took 5 and 3 h with MB, respectively. CR and AR adsorption on CTAB/MB remained above 85% with solution pH of 4 ~ 11, and these values kept over 85% and 92% over 5 recycle runs. The adsorption kinetics and equilibrium data followed the pseudo-second order kinetic mode and Langmuir adsorption isothermal model. The adsorption mechanism included ion exchange, electrostatic attraction and surface adsorption. Therefore, CTAB/MB is a promising adsorbent for dyes removal from wastewaters.