Rapid in situ microwave synthesis of Fe3O4@MIL-100(Fe) for aqueous diclofenac sodium removal through integrated adsorption and photodegradation

Metal-Organic Frameworks (MOFs) are efficient adsorbent and catalyst, however, the prepare of MOFs can be extremely time consuming. The rapid in situ microwave synthesis process offers the possibility of MOFs to a large-scale application. In this study, Fe3O4@MIL-100(Fe) was rapidly prepared via microwave in 30 min using Fe3O4 as metal precursor and applied as the adsorbent and photocatalyst to remove diclofenac sodium (DCF) from water. Fe3O4@MIL-100(Fe) exhibited an excellent adsorption effect to DCF with the maximum adsorption capacities of 400 mg/L. The presence of H2O2 could promote the removal of DCF during photocatalytic process. Approximately 99.4% of the DCF was removed in Fe3O4@MIL-100(Fe)/vis/H2O2 system via adsorption removal and consequent photocatalytic degradation. The high efficiency was attributed to the large BET surface area (1244.62 m2/g) and abundant iron metal sites (Fe(III) and Fe(II)) of Fe3O4@MIL-100(Fe). The adsorptive, photocatalytic property of Fe3O4@MIL-100(Fe) and the Fenton-like reaction were the main mechanisms for DCF removal. TOC analyzer was served to assess the mineralization of solutions treated by Fe3O4@MIL-100(Fe)/vis/H2O2 in 12 h. High elimination of TOC (87.8%) was observed during the DCF mineralization process. In addition, the major products were illuminated using HPLC-Q-TOF-MS and DCF degradation pathways were also proposed.