Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, School of Environmental and Chemical Engineering, Nanchang Hangkong University , Nanchang 330063, China.
School of Materials Science and Engineering, Nanchang Hangkong University , Nanchang 330063, China.
ACS Appl Mater Interfaces. 2017 Nov 22;9(46):41043-41054. doi: 10.1021/acsami.7b13443. Epub 2017 Nov 8.
Herein, we studied the adsorption behaviors of organic micropollutants, such as anticonvulsant carbamazepine (CBZ) and antibiotic tetracycline hydrochloride (TC), on zirconium metal-organic framework UiO-66 in water. The maximum adsorption capacities of CBZ and TC on the UiO-66 were 37.2 and 23.1 mg·g at 25 °C, respectively. The adsorption isotherms and kinetics of CBZ and TC were well described by using the Langmuir model and pseudo-second-order model, respectively, and the adsorptions on UiO-66 are endothermic reactions. The adsorption capacities of CBZ and TC on UiO-66 were decreased with the increase of solution pH. The presence of humic acid could improve the adsorption of CBZ and TC on UiO-66, but K ion inhibited their adsorption obviously. In addition, Ca and Al ions also suppressed the adsorption of TC on UiO-66. The competitive adsorption suggested that the adsorption sites for CBZ on UiO-66 were different from those for TC. The surface interactions between UiO-66 and the two micropollutants were demonstrated by powder X-ray diffraction, Fourier transform infrared (FT-IR) spectra, scanning electron microscopy, nitrogen adsorption/desorption isotherms, and X-ray photoelectron (XPS) spectra. The characterizations showed that the adsorption of CBZ on UiO-66 is mainly a physisorption, and the hydrophobic effect played a crucial role during the adsorption of CBZ; meanwhile weak π-π electron donor-acceptor interaction and electrostatic attraction also existed. However, the adsorption of TC on UiO-66 is mainly a chemisorption; in addition to the strong electrostatic attraction and π-π electron donor-acceptor interaction forces, the nitrogenous groups of TC played an important role, which can replace the carboxylic groups coordinated with Zr-O clusters. The obtained results will aid us to comprehend the surface interaction between organic micropollutants and UiO-66 and expand the application of UiO-66 as sorbent for removal of pollutants from water.
在此，我们研究了有机微量污染物（如抗惊厥药卡马西平（CBZ）和抗生素盐酸四环素（TC））在水中对锆基金属有机骨架 UiO-66 的吸附行为。在 25°C 下，CBZ 和 TC 在 UiO-66 上的最大吸附容量分别为 37.2 和 23.1 mg·g。CBZ 和 TC 的吸附等温线和动力学均可用 Langmuir 模型和拟二级模型很好地描述，吸附是吸热反应。CBZ 和 TC 在 UiO-66 上的吸附容量随溶液 pH 的升高而降低。腐殖酸的存在可以提高 CBZ 和 TC 在 UiO-66 上的吸附，但 K 离子明显抑制了它们的吸附。此外，Ca 和 Al 离子也抑制了 TC 在 UiO-66 上的吸附。竞争吸附表明，CBZ 在 UiO-66 上的吸附位与 TC 不同。粉末 X 射线衍射、傅里叶变换红外（FT-IR）光谱、扫描电子显微镜、氮吸附/脱附等温线和 X 射线光电子能谱（XPS）对 UiO-66 和两种微量污染物之间的表面相互作用进行了证明。这些特征表明，CBZ 在 UiO-66 上的吸附主要是物理吸附，疏水性在 CBZ 吸附过程中起着关键作用；同时，也存在较弱的π-π 电子供体-受体相互作用和静电引力。然而，TC 在 UiO-66 上的吸附主要是化学吸附；除了强静电引力和π-π 电子供体-受体相互作用力外，TC 的含氮基团也起着重要作用，它可以取代与 Zr-O 簇配位的羧酸基团。研究结果将有助于我们理解有机微量污染物与 UiO-66 之间的表面相互作用，并拓展 UiO-66 作为去除水中污染物的吸附剂的应用。
