Catalysis and Separation Processes Group, Chemical Engineering and Materials Department, Chemistry Sciences Faculty, Complutense University, Avda. Complutense s/n, 28040, Madrid, Spain.
Chemical Engineering Department, National University of Saint Agustine, Av. Independencia s/n, Arequipa, Peru.
Environ Sci Pollut Res Int. 2019 Aug;26(22):22372-22388. doi: 10.1007/s11356-019-05597-x. Epub 2019 Jun 1.
The aim of this work is to synthesize a magnetic magnetite/multi-walled carbon nanotube (FeO/MWCNT) catalyst by a method combining co-precipitation and hydrothermal treatments for the efficient removal of diclofenac (DCF) by catalytic wet peroxide oxidation (CWPO). The support (MWCNTs) shows a moderate-large surface area and good adsorption capacity, leading to the improvement of the magnetite (FeO) dispersion on its surface. The response surface methodology (RSM) was applied in order to find out the effect of the reaction parameters on DCF removal, allowing to establish the optimum operating conditions (T = 60 °C, [HO] = 2.7 mM, [catalyst] = 1.0 g L). The optimum CWPO experiment showed an outstanding catalytic activity at non-modified pH solution (6.7), obtaining a 95% of DCF removal after 3 h reaction time; this high efficiency can be attributed to the synergistic effect of the iron-based catalyst with the high quantity of OH radicals generated on the surface of the catalyst. In addition, the FeO/MWCNT material exhibited good reusability along three consecutive reaction cycles, finding a pollutant removal close to 95% in each cycle of 3 h reaction time. Additionally, a degradation mechanism pathway was proposed for the removal of DCF by CWPO. The versatility of the material was finally demonstrated in the treatment of different environmentally relevant aqueous matrices (a wastewater treatment plant effluent, surface water, and hospital wastewater), obtaining an effective reduction in the ecotoxicity values.
本工作旨在通过联合共沉淀和水热处理方法合成磁性磁铁矿/多壁碳纳米管（FeO/MWCNT）催化剂，以用于通过催化湿式过氧化物氧化（CWPO）有效去除双氯芬酸（DCF）。载体（MWCNTs）具有中等大的表面积和良好的吸附能力，从而改善了磁铁矿（FeO）在其表面的分散性。应用响应面法（RSM）来找出反应参数对 DCF 去除的影响，从而可以确定最佳操作条件（T=60°C，[HO]=2.7mM，[催化剂]=1.0gL）。最佳 CWPO 实验在非改性 pH 溶液（6.7）下表现出出色的催化活性，在 3 小时反应时间后可获得 95%的 DCF 去除率；这种高效率可归因于铁基催化剂与催化剂表面上生成的大量 OH 自由基的协同作用。此外，FeO/MWCNT 材料在三个连续的反应循环中表现出良好的可重复使用性，在每个 3 小时反应时间的循环中，去除污染物的效率接近 95%。此外，提出了 CWPO 去除 DCF 的降解机制途径。最后，该材料的多功能性在处理不同环境相关的水基基质（污水处理厂出水、地表水和医院废水）中得到了证明，有效地降低了生态毒性值。
