The advanced oxidation technology based on sulfate radical has been applied to the treatment of various organic wastewater because of its strong oxidizability and wider pH range. Fe-MOFs materials with abundant active sites and pores were often used to activate persulfate, but their catalytic activity needed to be further improved. Therefore, in this paper, MIL-101(Fe,Co) composites were prepared by doping Co, which improved the catalytic performance of Fe-MOFs. CoFe2O4/MIL-101(Fe,Co) composite was prepared by compounding magnetic CoFe2O4, which further improved the recoverability and stability of MIL-101(Fe,Co) catalyst. The catalysts were characterized by XRD, SEM, BET, FT-IR, XPS and other techniques. The performance of Co modified MIL-101(Fe) composite activated PS to degrade methyl orange was investigated, and its catalytic mechanism was explored. The specific research results were as follows :
MIL-101(Fe,Co) composite was prepared by solvothermal method. The composite has octahedral structure with Fe-O and Co-O characteristic peaks. When the molar ratio of Co to Fe was 1:5, the catalytic activity was the best. At room temperature, when pH=3, the concentration of methyl orange was 10 mg/L, 0.03 g/L PS and 0.2 g/L MIL-101(Fe,Co) were added, the reaction was 140 min, and the removal rate of methyl orange reached 96.86%. The degradation of methyl orange was mainly catalyzed by heterogeneous reaction to produce •O2−, •SO4- and •OH.
CoFe2O4/MIL-101(Fe,Co) composites with good mesoporous structure were prepared by solvothermal method by adding CoFe2O4 into MIL-101(Fe,Co) precursor. When the mass ratio of CoFe2O4 to MIL-101(Fe,Co) was 1:3, it showed higher catalytic activity. At room temperature, when pH = 7, the concentration of methyl orange was 10 mg/L, 0.09 g/L PS and 0.3 g/L CoFe2O4/MIL-101(Fe,Co) were added, the removal rate of methyl orange reached 98.57% after 140 min. The CoFe2O4/MIL-101(Fe,Co) composite material not only overcome the agglomeration problem of CoFe2O4, but also maintained the framework structure of MOFs, and degraded methyl orange by producing •SO4- and •OH through homogeneous and heterogeneous catalysis. The CoFe2O4/MIL-101(Fe,Co) composite material can be recovered by magnetic recycling, and has good reusability and stability.
谷歌
火狐
