Study On The Applicability Of MIL-101(Fe) Doped With Metal Ions For The Removal Of Water Contaminants Via Persulfate Activation

Metal-organic framework（MOFs）,self-assembled with metal ions and organic ligands,are crystalline porous materials with structure diversity and chemical varieties.These characteristics allowed MOFs to be widely used in chemical catalysis,gas separation and energy storage.With the rapid development of advanced oxidation technologies based on sulfate radicals,a number of Fe-based MOFs have gained attention in the field of persulfate activation.In this work,we illustrated the synthesis of Co（Ⅱ）or Cu（Ⅱ）supported MIL-101（Fe）.Co-MIL-101（Fe）and Cu-MIL-101（Fe）were prepared by post-synthesis modification（POSM）,MIL-101（Fe,Cu）was synthesized via pre-synthesis modification（PRSM）.All of catalysts were tested to activate per sulfate（PS）for removal of water contaminants.The main research contents and conclusions are as follows:（1）Preparation,characterization and catalytic performance of Co-MIL-101（Fe）and Cu-MIL-101（Fe）Co-MIL-101（Fe）and Cu-MIL-101（Fe）were prepared by the means of POSM on the basis of MIL-101（Fe）synthesized with hydrothermal method.Catalysts,Co-MIL-101（Fe）,Cu-MIL-101（Fe）and MIL-101（Fe）,were employed to catalyze persulfate to oxidize Acid Orange 7（AO7）.The addition of Cu²⁺ and Co²⁺ brought about great changes in crystalline structure and morphology appearance.Moreover,Co doping caused greater changes in comparison with Cu doping.The sequence of catalytic performance from high to low was: Co-MIL-101（Fe）,Cu-MIL-101（Fe）,MIL-101（Fe）.Catalysts exhibited better catalytic performance: the addition amount of metal ions was 8%,the dosage amount of persulfate was 8mM/L.The AO7 degradation was mainly ascribed to the sulfate radicals.What’s more,there was the loss of iron ion form catalysts during persulfate activation.（2）Preparation,characterization and catalytic performance of MIL-101（Fe,Cu）The MIL-101（Fe,Cu）catalyst was prepared by the method of PRSM,with substitute Cu²⁺ for Fe³⁺.MIL-101（Fe,Cu）was tested to activate persulfate（PS）for removal of Rhodamine B in water.Cu doping also altered structure characteristics of MIL-101（Fe）.The catalytic performance of MIL-101（Fe,Cu）was superior to that of MIL-101（Fe）.pH value was an important parameter,and MIL-101（Fe,Cu）could showed better catalytic ability in the range of p H=2.68-4.（3）Catalysts on the removal of Dibutyl phthaate（DBP）In view of the above researches,MIL-101（Fe）,8%wtCo-MIL-101（Fe）,8%wtCu-MIL-101（Fe）and MIL-101（Fe,Cu）-4# were investigated to the degradation of DBP.The best removal rate of 84.5% was achieved by 8%Co-MIL-101（Fe）.（4）The role of metal dopingThe loaded content of metal was below 1wt% actually.Such an enhancement in activity may be attributed to the main reasons: an increase number of active Fe sites produced by Co and Cu doping;the alteration of BET and SEM could promoted the catalytic ability.