MOF-253 Modified Micro-reactor For Catalytic Degradation Of Organic Pollutants

In recent years,the problems of water shortage and water pollution have become increasingly serious.Among the organic pollutants,organic dyes have a serious impact on human health.Photocatalytic technology has the advantages of environmentally friendly,clean and efficient,therefore,is a promising technique in the field of waste water treatment.Metal-organic frameworks?MOFs?have the advantages in large specific surface area,tunable structure,and some MOFs show semiconductor characteristics,they have been intensively studied in photocatalytic applications.Micro-reactors have large surface area-to-volume ratio and microchannels,which can achieve instantaneous mixing,which are the factors favorable for photocatalysis.In this thesis,MOFs based catalyst was anchored in-situly on the inner surface channel of the microreactor to form a catalytic microreactor in one-piece.The obtained microreactor was examined in the continuous photocatalytic degradation of organic dyes.The main research contents of this thesis are as follows:?1?An aluminum-based MOF,namely MOF-253 was synthesized by solvothermal method,and the photocatalyst AgI was immobilized on MOF-253,then the AgI/MOF-253 composite materials with different molar ratios were synthesized and characterized by XRD,SEM,FTIR,UV-Vis DRS and nitrogen adsorption analysis.The photocatalytic degradation of the organic dye Rhodamine B?RhB?was selected as the model reaction to study the catalystic efficiency of AgI/MOF-253.The loading amount of AgI and the concentration of hydrogen peroxide on the performance of visible light catalytic degradation of RhB were also investigated.The results show that the molar ratio of AgI to MOF-253 and concentration of H₂O₂ have an important effect on the performance of the catalyst.The optimized reaction system can degrade RhB up to96%within 60 min.It can be recycled 4 times and the degradation efficiency remains above95%.?2?A home-made planar microreactor was used to carry out the photocatalytic reaction,and the thin layer of MOF-253 was self-assembled on the surface of the inner channels of micro-reactor groove by reactive seeding method,AgI was immobilized on the thin layer of MOF-253 afterwards.The obtained AgI/MOF-253 microreactor was characterized by XRD,FTIR and SEM.The degradation of RhB was operated under LED visible light,the effect of hydrogen peroxide concentration,residence time and other factors on the catalytic degradation reaction was explored.The results show that 0.04 mol/L hydrogen peroxide is the best concentration in this reaction system.At the same time,when the residence time is 20 s,the photocatalytic efficiency can reach 95%in this condinuous microreactor systhem,and the photodegridation efficiency of over 90%has been maintained for 50 hours.