Efficient and stable iron-copper montmorillonite heterogeneous Fenton catalyst for removing Rhodamine B

[Display omitted] •Fe/Cu-MMT was prepared by a two-step strategy of impregnation and calcination.•Fe/Cu-MMT exhibited excellent heterogeneous catalytic activity and reusability under neutral conditions.•The coexistence of the redox cycles of Fe3+/Fe2+ and Cu2+/Cu+ could facilitate the interfacial electron transfer of MMT. In this work, iron-copper supported montmorillonite heterogeneous Fenton catalyst (Fe/Cu-MMT) was successfully prepared by a two-step strategy of impregnation and calcination for removing Rhodamine B (RhB) from aqueous solution. The insertion of Fe and Cu expanded the pores size and improve the thermal stability of the initial montmorillonite, making the supported clay more suitable as a heterogeneous Fenton catalyst. The decolorization efficiency and the TOC removal of RhB under the optimal operating conditions of 1.5 g·L−1 Fe/Cu-MMT, 5 mmol ·L−1 H2O2 and pH 7.0 within 90 min could reach 98.4% and 87.9%, respectively. Notebly, the discoloration ratio of RhB still reached 87.5% after the 10th cycle experiment. In addition, the active radical capture experiments and EPR spectra revealed that both hydroxyl radicals (·OH) and superoxide radicals (·O2−) played a main function in the mineralization of RhB. Therefore, the as-prepared Fe/Cu-MMT with the advantages of high efficiency, good reusability and low cost provided a promising approach for the removing of dyes from solution.