College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
College of Environmental Science and Engineering, Hunan University, Changsha, Hunan 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan 410082, China.
Chemosphere. 2019 Jun;224:910-921. doi: 10.1016/j.chemosphere.2019.02.193. Epub 2019 Mar 2.
Iron-based magnetic materials are deemed to be promising catalysts for various catalytic reactions and can be recovered conveniently by an external magnetic field. MnFeO nanoparticle and MnFeO/bio-char composite with different bio-char contents were prepared to activate hydrogen peroxide for the degradation of tetracycline (TC). The catalysts were characterized by SEM, BET, XRD, FTIR, VSM and XPS. The results indicated that MnFeO had a spherical shape and was successfully loaded onto the surface of bio-char. The introduction of bio-char effectively suppressed the aggregation of MnFeO and drastically increased the specific surface area. Both MnFeO and MnFeO/bio-char composite can be separated easily by an external magnetic field. Using 1:2 composite as heterogeneous photo-Fenton catalyst obtained a degradation of 95% through visible light irradiation of 40 mg Lsolution at natural pH (pH = 5.5) in the presence of 100 mmol L HO for 2 h. Free radical quenching experiment and the ESR results confirm that hydroxyl radicals play the main role for TC degradation. XPS measurements show that both Fe and Mn ions simultaneously participate in the activation of HO. The bio-char not only restrains the aggregation of MnFeO leading to the improved removal efficiency of TC, but also has side effects by consuming hydroxyl radicals. By cyclic degradation experiments, the performance of MnFeO/bio-char composite is stable and almost unchanged, and the leaching metal ions of both Fe and Mn are neglectful (both below 0.2 mg L). Besides, steady performance of MnFeO/bio-char catalyst to remove TC from tap water and river water has been certified.
铁基磁性材料被认为是各种催化反应有前途的催化剂，并可以通过外部磁场方便地回收。制备了不同生物炭含量的 MnFeO 纳米颗粒和 MnFeO/生物炭复合材料，以活化过氧化物过氧化氢用于四环素（TC）的降解。通过 SEM、BET、XRD、FTIR、VSM 和 XPS 对催化剂进行了表征。结果表明，MnFeO 呈球形，并成功负载在生物炭表面。生物炭的引入有效抑制了 MnFeO 的聚集，并大大增加了比表面积。MnFeO 和 MnFeO/生物炭复合材料都可以通过外部磁场轻松分离。使用 1:2 复合材料作为非均相光芬顿催化剂，在自然 pH（pH=5.5）下，在 100mmol L HO 存在下，通过可见光照射 40mg Lsolution 2 h，可获得 95%的降解。自由基猝灭实验和 ESR 结果证实，羟基自由基在 TC 降解中起主要作用。XPS 测量表明，Fe 和 Mn 离子同时参与 HO 的活化。生物炭不仅抑制了 MnFeO 的聚集，从而提高了 TC 的去除效率，而且通过消耗羟基自由基产生副作用。通过循环降解实验，MnFeO/生物炭复合材料的性能稳定且几乎不变，且浸出的 Fe 和 Mn 金属离子可以忽略不计（均低于 0.2mg L）。此外，MnFeO/生物炭催化剂在去除自来水中和河水中的 TC 方面表现出稳定的性能。
