Department of Environmental Health Engineering, School of Public Health, Alborz University of Medical Sciences, Karaj, Iran.
Research Center of Health, Safety and Environment, Department of Environmental Health Engineering, Faculty of Evaz Health, Larestan University of Medical Sciences, Lar, Larestan, Iran.
Environ Sci Pollut Res Int. 2020 Dec;27(36):45324-45335. doi: 10.1007/s11356-020-10427-6. Epub 2020 Aug 12.
The cobalt ferrite loaded on multi-walled carbon nanotubes (MWCNTs-CoFeO) was synthesized and used as a novel catalyst for the degradation of mefenamic acid (MFA) in the presence of peroxymonosulfate (PMS). The results showed that MWCNTs-CoFeO has higher catalytic performance in the activation of PMS and degradation of MFA compared with MWCNTs, Co, Fe, and CoFeO. The highest kinetic constant rate (0.0198 min) and MFA degradation (97.63%) were obtained at pH = 7, PMS = 4 mM, catalyst = 500 mg/L, MFA = 10 mg/L, and time = 150 min. MFA degradation accelerated with increasing PMS and catalyst dosage but decreased by initial pH. The influence of different anions and water matrix on the catalytic system was investigated, and the results explained a decrease in the MFA rate in the presence of the interfering substances. Scavenging experiments showed that both sulfate radical anion (SO) and hydroxyl radical (OH) were effective on MFA degradation, but SO had a greater effect on the degradation of MFA. In addition, the stability and recyclability of MWCNTs-CoFeO were evaluated in the consecutive reaction cycle; the MFA degradation rate reached 89.75% after 4 cycles of reaction. The MFA degradation products were identified by gas chromatography-mass spectrometry (GC-MS) and their degradation pathway was suggested. Finally, a comparison was conducted among the methods used for PMS activation, and the results showed that the cobalt ferrite-based catalyst has high degradation efficiency. However, ultrasound, heat, and ultraviolet (UV) processes can be used to improve the degradation rate of the MWCNTs-CoFeO/PMS system at different reaction times.
负载于多壁碳纳米管上的钴铁氧体（MWCNTs-CoFeO）被合成并用作过一硫酸盐（PMS）存在下降解甲芬那酸（MFA）的新型催化剂。结果表明，MWCNTs-CoFeO 在激活 PMS 和降解 MFA 方面比 MWCNTs、Co、Fe 和 CoFeO 具有更高的催化性能。在 pH = 7、PMS = 4 mM、催化剂 = 500 mg/L、MFA = 10 mg/L 和时间 = 150 min 的条件下，获得了最高的动力学常数速率（0.0198 min）和 MFA 降解率（97.63%）。MFA 降解随 PMS 和催化剂用量的增加而加速，但随初始 pH 值的降低而降低。研究了不同阴离子和水基质对催化体系的影响，结果解释了在存在干扰物质时 MFA 速率的降低。清除实验表明，硫酸根自由基（SO）和羟基自由基（OH）对 MFA 降解均有效，但 SO 对 MFA 的降解影响更大。此外，还评估了 MWCNTs-CoFeO 在连续反应循环中的稳定性和可回收性；在 4 个反应循环后，MFA 降解率达到 89.75%。通过气相色谱-质谱联用仪（GC-MS）鉴定了 MFA 降解产物，并提出了其降解途径。最后，对用于激活 PMS 的方法进行了比较，结果表明钴铁氧体基催化剂具有较高的降解效率。然而，超声、热和紫外线（UV）过程可以在不同的反应时间下用于提高 MWCNTs-CoFeO/PMS 体系的降解速率。
