Magnetic nanoparticles of multi-metal co-doped magnesium ferrite (MgFe₂O₄) were synthesized from saprolite laterite ore by a hydrothermal method, and firstly proposed as a heterogeneous photon-Fenton-like catalyst for degradation of Rhodamine B (RhB). The factors that influence the degradation reaction including pH value, the concentration of H₂O₂ and the amount of catalyst, were systematically investigated. The doped MgFe₂O₄ exhibited a degradation efficiency up to 96.8%, and the chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies about 85.6% and 68.3%, respectively, under visible light illumination for 180 min. The high activity is mainly attributed to the high specific surface area of the catalyst and the synergistic interaction between photo-catalytic oxidation and Fenton-like oxidation. Moreover, the catalyst also showed good stability and recycling performance for degrading RhB. After five consecutive degradation cycles, the activity decayed no more than 10%. Compared to other catalysts prepared from pure chemical agents, the multi-metal co-doped MgFe₂O₄ is more competitive due to its high activity, good stability, ease of recollection, and especially the use of saprolite laterite ore as precursor. This work may provide a new avenue to synthesize efficient ferrite catalysts for degrading organic pollutants in wastewater by using natural minerals.

利用水热法从腐泥土中合成了多金属共掺杂镁铁氧体（MgFe ₂ O ₄）的磁性纳米粒子，首次提出了一种用于降解罗丹明B（RhB）的非均相光子-芬顿状催化剂。系统地研究了影响降解反应的因素，包括pH值，H ₂ O ₂浓度和催化剂用量。掺杂的MgFe ₂ O ₄在可见光照射180分钟后，其降解效率高达96.8％，化学需氧量（COD）和总有机碳（TOC）去除效率分别约为85.6％和68.3％。高活性主要归因于催化剂的高比表面积以及光催化氧化和类芬顿氧化之间的协同相互作用。此外，该催化剂还显示出良好的稳定性和用于降解RhB的再循环性能。在连续五个降解循环后，活性下降不超过10％。与其他由纯化学试剂制备的催化剂相比，多金属共掺杂MgFe ₂ O ₄由于其高活性，良好的稳定性，易于回收，尤其是使用腐泥土红土矿石作为前体，因而具有更高的竞争力。这项工作为利用天然矿物合成降解废水中有机污染物的高效铁氧体催化剂提供了一条新途径。