Construction Of Co(Ⅱ)-MOF Based On Conjugated Triazine And Di-acid Ligands And Its Fenton-like Properties

Water pollution caused by persistent organics have become an increasing issue for the society development.Sulfate radical-based advanced oxidation progress could directly degrade organics into small molecules such as H₂O and CO₂in the presence of a qualified catalyst,and it was considered as a sustainable water treatment technology.Among the transition metals,cobalt-based materials had the best activation performance.However,they were limited by high cost,high leaching,difficult reutilization,and secondary pollution.Metal-organic Framework（MOFs）have been widely applied in manyresearch fields including catalysis,fluorescence sensing,gas adsorption and separation,due to their controllable structure and easy functionalization.However,their self-assembly synthetic process was affected by many factors including solvent,temperature and solution p H.Therefore,the design and synthesis of water-stable MOFs with specific functions and low leaching is a promising issue.This thesis focused on the synthesis and analysis of novel MOFs,and their applications in peroxymonosulfate（PMS）-based Fenton-like reaction for tetracycline（TC）removal.Co（II）-MOF was synthesized by solvothermal method using triazine and isophthalic acid as organic ligands.The parameters in degradation process and the catalytic mechanism were studied in detail.The main research contents are as follows:（1）A organic ligand named as 2,4,6-tris（4-pyridine）-1,3,5-triazine were synthesized.It was selected as one of the component for preparation of Co（II）-MOF,Co₄（TPT）₄（m-BDC）₄·H₂O through a solvothermal reaction with isophthalic acid.Single crystal X-ray diffraction revealed that the as-synthesized Co₄（TPT）₄（m-BDC）₄·H₂O was crystallized in the monoclinic system with a three-dimensional framework structure.Furthermore,this MOF was characterized by TGA experiments,and the results indicated that this MOF had good thermal stability.Therefore,it could be served as a candidate for PMS activation.（2）The activity of as-obtained Co₄（TPT）₄（m-BDC）₄·H₂O in Fenton-like reaction toward TC was evaluated.The factors on the degradation reaction was explored and the optimized condition was 10 mg catalyst and 30 mg PMS for degrading 30 mg/L TC.The main active species involved in the degradation was SO₄^·-and^·OH,and the possible catalytic mechanism was deduced.The stability of Co₄（TPT）₄（m-BDC）₄·H₂O was evaluated by recycle experiment,since of 77%degradation efficiency were still well-preserved.This article provides a new idea for the construction of a stable and efficient cobalt-based MOF,and realizes the efficient degradation of organic pollutants.