Department of Environmental Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea.
Department of Battery Convergence Engineering, Kangwon National University, Chuncheon, 24341, Republic of Korea.
Chemosphere. 2024 Feb;349:140788. doi: 10.1016/j.chemosphere.2023.140788. Epub 2023 Nov 30.
Diclofenac (DCF) is frequently detected in water bodies (ng/L to g/L) as it is not completely removed by conventional wastewater treatment plants. Adsorption and photocatalysis have been studied as promising methods for treating DCF; however, both processes have limitations. Thus, in this study, the removal efficiency of DCF is evaluated using a magnetite/reduced graphene oxide (FeO/RGO) nanocomposite via a coupled adsorption-catalysis process. The FeO/RGO nanocomposite was successfully synthesized using a microwave-assisted solvothermal method and exhibited a bandgap of 2.60 eV. The kinetic data best fitted the Elovich model (R = 0.994, χ = 0.29), indicating rapid adsorption. The maximum DCF adsorption capacity calculated using the Langmuir model was 80.33 mg/g. An ultraviolet C (UVC) light source and 0.1 g/L of FeO/RGO nanocomposite were the optimum conditions for the removal of DCF (C = 30 mM) by a coupled adsorption-photocatalysis process (first-order rate constant (k) = 0.088/min), which was greater than the single adsorption (k = 0.029/min) and pre-adsorption and post-photocatalysis (k = 0.053/min) processes. This indicates that the adsorbed DCF did not hamper the photocatalytic reaction of the FeO/RGO nanocomposite, but rather enhanced the coupled adsorption-photocatalytic reaction. DCF removal efficiency was higher at acidic conditions (pH 4.3-5.0), because high H promotes the generation of certain reactive oxygen species (ROS) and increases of electrostatic interaction. The presence of NaCl and CaCl (10 mM) did not notably affect the total DCF removal efficiency; however, Ca affected the initial DCF adsorption affinity. Scavenger experiments demonstrated O and h play a key ROS than ·OH to degrade DCF. The acute toxicity of DCF towards Aliivibrio fischeri gradually decreased with increasing treatment time.
双氯芬酸（DCF）在水体中经常被检测到（ng/L 至 g/L），因为常规废水处理厂无法完全去除它。吸附和光催化已被研究为处理 DCF 的有前途的方法；然而，这两种方法都存在局限性。因此，在这项研究中，通过耦合吸附-催化过程，使用磁铁矿/还原氧化石墨烯（FeO/RGO）纳米复合材料来评估 DCF 的去除效率。FeO/RGO 纳米复合材料是通过微波辅助溶剂热法成功合成的，具有 2.60 eV 的带隙。动力学数据最符合 Elovich 模型（R = 0.994，χ = 0.29），表明吸附速度很快。使用 Langmuir 模型计算的最大 DCF 吸附容量为 80.33 mg/g。对于通过耦合吸附-光催化过程去除 DCF（C = 30 mM），最佳条件是使用紫外线 C（UVC）光源和 0.1 g/L 的 FeO/RGO 纳米复合材料（一级速率常数（k）= 0.088/min），这大于单一吸附（k = 0.029/min）和预吸附和后光催化（k = 0.053/min）过程。这表明吸附的 DCF 并没有阻碍 FeO/RGO 纳米复合材料的光催化反应，而是增强了耦合的吸附-光催化反应。在酸性条件下（pH 4.3-5.0），DCF 的去除效率更高，因为高 H 促进了某些活性氧物质（ROS）的生成，并增加了静电相互作用。存在 NaCl 和 CaCl（10 mM）并没有显著影响总 DCF 去除效率；然而，Ca 会影响初始 DCF 吸附亲和力。猝灭实验表明，O 和 h 比·OH 更能产生关键的 ROS 来降解 DCF。DCF 对发光菌 Aliivibrio fischeri 的急性毒性随着处理时间的增加而逐渐降低。
