Synthesis Of Fe-based MOF Derivatives And Their Applications In Adsorption And Photocatalytic Degradation Of Volatile Organic Compounds

Volatile organic compounds（VOCs）are the key precursors of secondary pollutants such as O₃ and PM_2.5,and have attracted world-wide attention regarding their serious hazards on ecological environment and human health.Oxygenated volatile organic compounds（OVOCs）have a significant contribution to the formation of these secondary pollutants due to their widespread presence and high reactivity.Adsorption and photocatalytic oxidation technology are the current potential and efficient approaches for the removal of VOCs.Adsorption can enrich VOCs through simple operation,while photocatalytic oxidation technology can convert VOCs into CO₂ and H₂O under the mild conditions.However,single adsorption or photocatalytic technology has problems such as secondary pollution,poor regeneration ability and low removal efficiency.Therefore,the development of materials with efficient adsorption and catalytic functions has great research significance and application prospects.Metal organic framework（MOFs）derived materials can not only inherit the characteristics of large specific surface area and high porosity from original MOFs,but also form hierarchical porous structure and have excellent electrical conductivity and chemical stability.MOFs derived materials often show better performance than the original MOFs in many fields.In view of this,this study prepared MOFs derived materials,and explored their adsorption and photocatalytic performances for VOCs.A series of Fe-based metal organic framework derived materials were prepared by thermal treating MIL-100（Fe）in nitrogen atmosphere for adsorption removal of OVOCs such as methanol,formaldehyde and acetone under dynamic conditions.The results showed that the partially carbonized M-350 material obtained by calcining MIL-100（Fe）at 350℃exhibited the best adsorption performance and high stability.The breakthrough adsorption capacity of M-350 for methanol was 61.5%higher than that of pure MIL-100（Fe）,and it was 24.7,6.5 and2.6 times higher than that of commercial activated carbon,ZSM-5 and SAPO-34 adsorbents,respectively.The excellent adsorption performance was attributed to the exposure of abundant coordinatively unsaturated iron metal sites acting as Lewis acid sites through high temperature calcination,which had a strong affinity for OVOCs.Meanwhile,a hierarchical porous structure and high specific surface area further promoted the adsorption.A series of Fe-based metal organic framework derived materials were prepared with MIL-100 as the precursor for static photocatalytic degradation of acetone under visible light.The experimental results showed that the pure MIL-100 showed good visible light photocatalytic activity,and the thermal treated derived materials showed significantly enhanced photocatalytic activity compared with the original MIL-100.M-300 exhibited the highest photocatalytic acetone removal efficiency and excellent cycle stability.The excellent photocatalytic performance of M-300 was attributed to the adsorption and photocatalytic synergistic removal of acetone.Meanwhile,the formation of Fe²⁺/Fe³⁺active sites promoted more·OH generation and inhibited electron-hole recombination,further improved the photocatalytic activity.