Adsorption properties, kinetics & thermodynamics of tetracycline on carboxymethyl-chitosan reformed montmorillonite
Adsorption properties, kinetics & thermodynamics of tetracycline on carboxymethyl-chitosan reformed montmorillonite
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吸附特性、动力学
DOI：
10.1016/j.ijbiomac.2018.11.235
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发表时间：
2019-03-01
影响因子：
8.2
通讯作者：
Zhu, Sidi
中科院分区：
文献类型：
--
作者：
Ma, Jianzhe;Lei, Yang;Zhu, Sidi
采用羧甲基壳聚糖（CMC）对钠基蒙脱土（Na-Mt）进行改性。采用傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、比表面分析仪（BET）和热重分析（TGA）对样品进行了表征。以四环素（泰特）和金霉素（CTC）两种常见的四环素类抗生素为代表污染物，在不同的实验条件下，研究了CMC-Mt对四环素类抗生素的吸附性能。X射线衍射分析表明，CMC的插层明显增大了蒙脱石的层间距，并在一定程度上提高了蒙脱石的吸附能力。结果表明，CMC-Mt对四环素类抗生素的吸附主要受pH值的影响，而不受温度的影响。此外，去除泰特和CTC迅速达到平衡的接触时间内2小时。吸附动力学数据由一级、二级动力学和粒内扩散模型确定。动力学研究表明，泰特和四氯化碳的吸附过程符合二级动力学。Freundlich等温线研究与实际数据一致，表明吸附过程是非均相的。此外，热力学研究表明，在较低的温度下，去除过程更自发，这意味着它是一个放热反应。合成的吸附剂CMC-Mt可广泛应用于废水处理。(C)2018 Elsevier B.V.版权所有。
This paper describes a modification method of Na-montmorillonite (Na-Mt) with carboxymethyl-chitosan (CMC). The as-prepared samples were analyzed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analyzer and thermogravimetric analysis (TGA). Two common tetracycline antibiotics, tetracycline (TET) and chlortetracycline (CTC), were selected as the represented pollutants and adsorbed by CMC-Mt under different experimental conditions. The intercalation of CMC obviously amplified the basal spacing of the interlayers confirmed by XRD measurements and improved the adsorption capacities of montmorillonite to some degree. The results showed that the tetracycline antibiotic sorption onto CMC-Mt was mainly dependent on pH and was not affected by temperature. Besides, the removal of TET and CTC rapidly attained an equilibrium within 2 h of contact time. The kinetic data of adsorption was determined by first order, second-order kinetics and intraparticle diffusion models. The kinetic study indicates that the TET and CTC adsorption processes obeyed the second-order kinetics. The Freundlich isotherm study was in agreement with the practical data, suggesting a heterogeneous sorption process. Furthermore, the thermodynamic studies revealed that the removal process was more spontaneous at a lower temperature, implying it an exothermic reaction. The synthesized adsorbent CMC-Mt can be widely used in the treatment of wastewater. (C) 2018 Elsevier B.V. All rights reserved.