College of Ocean Technique and Environment Department, Dalian Ocean University, Dalian, Liaoning Province, China.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2020;55(5):573-584. doi: 10.1080/10934529.2020.1717275. Epub 2020 Jan 25.
In this study, lanthanum modified zeolite (La-Z) was used to adsorb chlortetracycline (CTC) from aquaculture wastewater. La-Z was characterized by SEM, TEM, EDS, XRD, FTIR and BET. The effects various factors on the adsorption of CTC by La-Z were investigated, including the lanthanum modification concentration on zeolites, the dosage of La-Z, solution pH and reaction time. Orthogonal experiments were performed to determine the optimal adsorption conditions. Adsorption kinetics were studied by quasi-first-order model, quasi-second-order model, Weber-Morris, Boyd and Bangham models, while isotherms were analyzed by the Langmuir and Freundlich models. The removal rate reached 98.4%, when the modified concentration was 0.02 mol/L, the adsorbent dosage was 0.04 g, the initial concentration of CTC was 5 mg/L, the adsorption time was 20 min, and the pH was 7. The initial CTC concentration had the greatest influence on the adsorption process. The kinetic results showed a significant linear correlation between the experimental results and the quasi-second-order kinetic model. From the results of the internal diffusion model, it was found that the La-Z adsorption rate was controlled by both internal diffusion and external diffusion, in a multi-step process. The adsorption isotherm conforms to the Langmuir model, with the maximum adsorption quantity reaching 127.55 mg/g. Thermodynamic analysis showed that the adsorption process was an endothermic process of entropy increase, which occurs spontaneously.
在这项研究中，采用镧改性沸石（La-Z）吸附养殖废水中的金霉素（CTC）。采用 SEM、TEM、EDS、XRD、FTIR 和 BET 对 La-Z 进行了表征。考察了不同因素对 La-Z 吸附 CTC 的影响，包括沸石上镧的改性浓度、La-Z 的用量、溶液 pH 和反应时间。通过正交实验确定了最佳吸附条件。通过拟一级动力学模型、拟二级动力学模型、Weber-Morris、Boyd 和 Bangham 模型研究了吸附动力学，通过 Langmuir 和 Freundlich 模型分析了等温线。当改性浓度为 0.02 mol/L、吸附剂用量为 0.04 g、CTC 初始浓度为 5 mg/L、吸附时间为 20 min、pH 值为 7 时，去除率达到 98.4%。初始 CTC 浓度对吸附过程的影响最大。动力学结果表明，实验结果与拟二级动力学模型具有显著的线性相关性。从内扩散模型的结果来看，La-Z 的吸附速率受到内扩散和外扩散的共同控制，是一个多步骤的过程。吸附等温线符合 Langmuir 模型，最大吸附量达到 127.55 mg/g。热力学分析表明，吸附过程是一个熵增的吸热过程，是自发进行的。
