Efficient Adsorptive Removal of Humic Acid from Water Using Zeolitic Imidazole Framework-8 (ZIF-8)
Efficient Adsorptive Removal of Humic Acid from Water Using Zeolitic Imidazole Framework-8 (ZIF-8)
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DOI：
10.1007/s11270-014-2280-7
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发表时间：
2015-02-01
影响因子：
2.9
通讯作者：
Chang, Hsuan-Ang
中科院分区：
文献类型：
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作者：
Lin, Kun-Yi Andrew;Chang, Hsuan-Ang
为了开发一种有效的腐殖酸吸附剂，本研究首次尝试研究沸石咪唑骨架从水中去除腐殖酸的能力。沸石咪唑骨架 8 (ZIF-8) 由于其在水溶液中的高稳定性而被特别选择作为 ZIF 原型来吸附腐殖酸。使用扫描电子显微镜（SEM）、粉末X射线衍射图（PXRD）、傅里叶变换红外光谱（FT-IR）和热重分析仪（TGA）合成并表征了ZIF-8，然后用于在各种条件下吸附腐殖酸。研究发现，ZIF-8 的结构在暴露于水中的腐殖酸后仍保持完整。研究了影响吸附的因素，包括固液比、混合时间、温度、pH、盐的存在和表面活性剂。研究发现ZIF-8的吸附能力远高于活性炭、粉煤灰、沸石、石墨等，显示出其去除腐植酸的巨大潜力。吸附机理可归因于ZIF-8的正表面与腐殖酸的酸性位点之间的静电相互作用，以及ZIF-8的咪唑与腐殖酸的苯环之间的p-p堆积相互作用。在酸性条件下，ZIF-8对腐殖酸的吸附能力增强，并且吸附过程在各种NaCl浓度的溶液中保持高度稳定。 ZIF-8还可以通过简单的乙醇洗涤过程再生并重新用于腐殖酸吸附。这些特性使 ZIF-8 成为一种高效、稳定的吸附剂，可去除水中的腐殖酸。
To develop an efficient adsorbent for humic acid, the present study represents the first attempt to investigate the capability of zeolitic imidazole frameworks to remove humic acid from water. Zeolitic imidazole framework-8 (ZIF-8) is particularly selected as a prototype ZIF to adsorb humic acid owing to its high stability in aqueous solutions. ZIF-8 was synthesized and characterized using scanning electronic microscopy (SEM), powder X-ray diffraction pattern (PXRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyzer (TGA) and then used to adsorb humic acid under various conditions. The structure of ZIF-8 was found to remain intact after the exposure to humic acid in water. Factors affecting the adsorption were examined, including solid-to-liquid ratio, mixing time, temperature, pH, presence of salt, and surfactants. The adsorption capacity of ZIF-8 was found to be much higher than that of activated carbon, fly ash, zeolites, graphite, etc., showing its promising potential for removal of humic acid. The adsorption mechanism could be attributed to the electrostatic interaction between the positive surface of ZIF-8 and the acidic sites of humic acid, as well as the p-p stacking interaction between imidazole of ZIF-8 and benzene rings of humic acid. The humic acid adsorption to ZIF-8 could be enhanced in the acidic conditions, and the adsorption process remained highly stable in the solutions of a wide range of NaCl concentrations. ZIF-8 can be also regenerated by simple ethanol-washing process and reused for humic acid adsorption. These features enable ZIF-8 to be an efficient and stable adsorbent to remove humic acid from water.