Geobacter mediated self-assembly preparation of MIL-100(Fe)@Fe3O4 for Fenton-like reaction catalysts

MIL-100(Fe)@Fe3O4 as an excellent magnetic nanomaterial is widely used in wastewater treatment, but the synthesis process is complex and some corrosive or biologically toxic modifiers are inevitable. Although microorganisms possess the potential to synthesize MIL-100(Fe)@Fe3O4 in mild conditions, the mechanisms of synthesis and interaction between microorganism and material remain to be investigated. Additionally, the biological characteristics of the biomaterial also need to be further evaluated. In this study, electroactive microorganism (EAM) was induced into the synthesis of MIL-100(Fe)@Fe3O4-B (MFeB) and the performance of MFeB was evaluated in Fenton-like systems. Compared with MIL-100(Fe)@Fe3O4-C (MFeC) by chemical synthesis, MFeB exhibited similar morphology and structure, but the larger mesoporous size (1.9 times) and stronger magnetism (1.3 times) were found with the exist of extracellular polymeric substance (EPS) produced by EAMs. MFeB exhibited more thorough phenol degradation effect, where the total organic carbon (TOC) removal rate was 1.2 times that in MFeC. Furthermore, MFeB displayed excellent catalytic stability and recovery performance with degradation rate still reached 100 % within 120 min after three cycles. This mainly depended on the EPS which avoided the surface passivation and iron loss in MFeB. These results highlighted the importance of EAMs in the field of biosynthetic materials due to the unique redox capability and found a simple strategy to prepare MIL-100(Fe)@Fe3O4 with stable catalytic performance.