College of Marine Science, Shanghai Ocean University, No 999 Hucheng Huan Road, Pudong District, Shanghai 201306, China.
J Hazard Mater. 2011 Oct 15;193:102-11. doi: 10.1016/j.jhazmat.2011.07.035. Epub 2011 Jul 19.
Surfactant-modified zeolites (SMZs) with various loadings of cetylpyridinium bromide (CPB) were used as adsorbents to remove tannic acid (TA) from aqueous solution. The TA adsorption efficiencies for natural zeolite and various SMZs were compared. SMZ presented higher TA adsorption efficiency than natural zeolite, and SMZ with higher loading amount of CPB exhibited higher TA adsorption efficiency. The adsorption of TA onto SMZ as a function of contact time, initial adsorbate concentration, temperature, ionic strength, coexisting Cu(II) and solution pH was investigated. The adsorbents before and after adsorption were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy. The adsorption kinetics of TA onto SMZ with CPB bilayer coverage (SMZ-CBC) followed a pseudo-second-order model. The equilibrium adsorption data of TA onto SMZ-CBC were well represented by Langmuir, Redlich-Peterson and Sips isotherm models. The calculated thermodynamic parameters indicated that TA adsorption onto SMZ-CBC was spontaneous and exothermic. The TA adsorption capacity for SMZ-CBC slightly decreased with increasing ionic strength but significantly increased with increasing Cu(II) concentration. The TA adsorption capacity for SMZ-CBC was relatively high at solution pH 4.0-7.0, and decreased with an increase in solution pH from 7.0 to 8.5. The mechanisms controlling TA adsorption onto SMZ-CBC at solution pH 5.5 include electrostatic attraction, hydrogen bonding and organic partitioning.
表面活性剂改性沸石（SMZ）用不同浓度的十六烷基溴化吡啶（CPB）作吸附剂，从水溶液中去除单宁酸（TA）。比较了天然沸石和各种 SMZ 的 TA 吸附效率。SMZ 表现出比天然沸石更高的 TA 吸附效率，并且 CPB 负载量更高的 SMZ 表现出更高的 TA 吸附效率。研究了 TA 在 SMZ 上的吸附作为接触时间、初始吸附物浓度、温度、离子强度、共存 Cu(II)和溶液 pH 的函数。吸附前后的吸附剂用 X 射线衍射（XRD）、场发射扫描电子显微镜（FE-SEM）、热重分析（TGA）和傅里叶变换红外（FT-IR）光谱进行了表征。CPB 双层覆盖（SMZ-CBC）上 TA 的吸附动力学遵循拟二级模型。TA 在 SMZ-CBC 上的平衡吸附数据由 Langmuir、Redlich-Peterson 和 Sips 等温线模型很好地表示。计算的热力学参数表明 TA 在 SMZ-CBC 上的吸附是自发和放热的。随着离子强度的增加，SMZ-CBC 对 TA 的吸附容量略有下降，但随着 Cu(II)浓度的增加而显著增加。SMZ-CBC 在溶液 pH 4.0-7.0 时的 TA 吸附容量较高，而当溶液 pH 从 7.0 增加到 8.5 时，TA 吸附容量降低。在溶液 pH 5.5 时控制 SMZ-CBC 上 TA 吸附的机制包括静电吸引、氢键和有机分配。
