Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, China.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Sci Rep. 2020 Feb 19;10(1):2960. doi: 10.1038/s41598-020-59850-2.
In this study, a novel, sustainable and efficient ceramsite substrate of constructed wetlands (CWs) were prepared for tetracycline (TC) removal by employing bentonite (Ben) and red mud (Rm) as the main materials and pine sawdust (Ps) as the additive. The optimal parameters for Ben/Rm/Ps ceramsite preparation were obtained via orthogonal and one-factor experimental designs, and the optimal parameters were presented as follows: mass ratio of Ben: Rm: Ps = 4:1:0.9, preheating temperature = 240 °C, preheating time = 20 min, calcining temperature = 1150 °C, and calcining time = 14 min. The properties of Ben/Rm/Ps-op ceramsite (obtained at the optimal condition) were first analyzed, including XRD and SEM, and demonstrated a microporous structure with some crystal strength components. Neutral condition and higher temperature were indicated conducive to improve the TC removal efficiency, while coexisting ions (Na or Ca) showed adverse effect for TC adsorption by Ben/Rm/Ps-op. In addition, adsorption kinetics and isotherm could be well described by the second-order kinetics and linear isothermal model, respectively, which suggested chemisorption and multilayer adsorption thickness increased infinitely. The theoretical maximum TC adsorption capacity of Ben/Rm/Ps-op at 20 °C reached up to 2.5602 mg/g. In addition, Ben/Rm/Ps-op could effectively remove TC as the CWs substrate under a dynamic flow condition. Further, Ben/Rm/Ps-op exhibited high reusability capability and stability for TC removal, and the adsorption amount still remained for 2.13 mg/g (C = 80 mg/L) after three consecutive cycles.
本研究以膨润土（Ben）和赤泥（Rm）为主要原料，松木屑（Ps）为添加剂，制备了一种新型、可持续、高效的人工湿地（CWs） Ceramsite 基质，用于去除四环素（TC）。通过正交和单因素实验设计得到了 Ben/Rm/Ps Ceramsite 制备的最佳参数，最佳参数为：Ben:Rm:Ps 的质量比=4:1:0.9，预热温度=240°C，预热时间=20min，煅烧温度=1150°C，煅烧时间=14min。首先分析了 Ben/Rm/Ps-op Ceramsite（在最佳条件下获得）的性能，包括 XRD 和 SEM，结果表明其具有微孔结构和一些晶体强度成分。中性条件和较高的温度有利于提高 TC 的去除效率，而共存离子（Na 或 Ca）对 Ben/Rm/Ps-op 的 TC 吸附则表现出不利影响。此外，吸附动力学和等温线可以分别很好地用二级动力学和线性等温模型来描述，这表明化学吸附和无限增加的多层吸附厚度。在 20°C 时，Ben/Rm/Ps-op 的最大理论 TC 吸附容量高达 2.5602mg/g。此外，Ben/Rm/Ps-op 在动态流动条件下作为 CWs 基质可以有效地去除 TC。进一步研究表明，Ben/Rm/Ps-op 对 TC 具有较高的重复利用能力和稳定性，在三个连续循环后，吸附量仍保持在 2.13mg/g（C=80mg/L）。
