State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China.
J Colloid Interface Sci. 2011 Feb 1;354(1):261-7. doi: 10.1016/j.jcis.2010.10.065. Epub 2010 Nov 2.
Extensive usage of tetracycline has resulted in its contamination in surface water and groundwater. The adsorption of tetracycline on zeolite beta was systematically investigated for the decontamination of the antibiotic polluted water in this study. Ninety percent of uptake by the zeolite beta occured in 0.25h, and the adsorption equilibrium was obtained within 3h, which was well described by an intraparticle diffusion model. The adsorption generally increased when pH was increased from 4.0 to 5.0, and then decreased significantly as the pH was further increased, which was caused by the pH-dependent speciation of tetracycline and surface charge of zeolite beta. Both Freundlich and Langmuir equations well described the adsorption isotherm. A thermodynamic analysis showed that the sorption process was spontaneous and endothermic. Aluminum atoms in the zeolite played a crucial role in the uptake; the adsorption increased with the increasing aluminum content in zeolite. The UV-Visible spectroscopy study showed that the spectra of tetracycline changed upon the interaction with zeolite beta, which could be ascribed to the formation of complexes of tetracycline and aluminum atoms in the zeolite surface. Nuclear magnetic resonance spectroscopy study further confirmed the participation of Al in the tetracycline adsorption. Fourier transform infrared spectroscopy studies showed that the amino functional groups in tetracycline were involved in the complexation with the zeolite surface.
四环素的广泛使用导致其在地表水和地下水中受到污染。本研究系统地研究了沸石β对受抗生素污染水的四环素的吸附作用，以实现对其的净化。沸石β在 0.25 小时内吸附了 90%的四环素，3 小时内达到吸附平衡，这一过程很好地符合内扩散模型。吸附通常随着 pH 值从 4.0 增加到 5.0 而增加，然后随着 pH 值的进一步增加而显著降低，这是由于四环素的 pH 依赖性形态和沸石β的表面电荷造成的。Freundlich 和 Langmuir 方程都很好地描述了吸附等温线。热力学分析表明，吸附过程是自发的和吸热的。沸石中的铝原子在吸附过程中起着关键作用，随着沸石中铝含量的增加，吸附量也随之增加。紫外可见光谱研究表明，四环素的光谱在与沸石β相互作用后发生了变化，这可归因于四环素和沸石表面铝原子形成的复合物。核磁共振波谱研究进一步证实了 Al 参与了四环素的吸附。傅里叶变换红外光谱研究表明，四环素中的氨基官能团参与了与沸石表面的络合。
