Application Of UiO-66 Based MOFs In Liquid Fuel Nitrogen Removal

Nitrogen-containing compounds in liquid fuel will generate various oxygen-containing nitride pollutants and discharged into the atmosphere after combustion,which will eventually cause very serious environmental problems;Nitrogen-containing compounds in liquid fuel may also cause decay of pipelines,pumps and other refining equipment in the refining process;Nitrogen-containing compounds in liquid fuel during use can also cause problems such as extinguishing of internal combustion engines.Therefore,removal of nitrogen-containing compounds from fuels is essential.Metal-Organic Frameworks(MOFs)are favored by researchers in the field of denitrification of liquid fuel because of their adjustable pore size and shape and easy modification of pore surface.However,the traditional MOFs materials have two shortcomings when adsorbing and denitrifying,one is that the adsorption selectivity for nitride is not high;the other is that the porosity decreases due to the blockage of some pore channels caused by their own aggregation.The defects in these two aspects largely affect the adsorption denitrification effect of MOFs.In view of the above research status,this paper carried out the following research work:Two kinds of Ui O-66-COOH materials were synthesized by carboxyl modification of MOF material Ui O-66 by two different preparation methods.The adsorption and denitrification properties of the prepared materials were studied.Firstly,the adsorption performance of the adsorption material Ui O-66-COOH without carboxyl modification was compared with that of bulk Ui O-66,so as to explore the effect of carboxyl modification on the adsorption performance.The experimental results showed that after carboxylic acid modification,the adsorption capacity of the MOF materials obtained by the two preparation methods for nitrogen-containing compounds was enhanced.Then,the adsorption properties of carboxyl-containing adsorbents prepared by different methods were compared,and the effects of different carboxyl modification methods on the adsorption properties were explored.It was found that the adsorption performance of carboxyl-containing MOF materials prepared by covalent bond modification method was better.Finally,the possible adsorption mechanism was proposed based on the experimental results,and the reuse performance of the adsorbent material was studied.A series of composite MOF materials with different doping ratios of graphene oxide were prepared.Composite MOF materials are divided into two systems,one is the doping system of Ui O-66 with graphene oxide,and the other is the doping system of Ui O-66-COOH with graphene oxide,which modifies carboxyl groups.The adsorption properties of various adsorbent materials on nitrogen-containing compounds in the two systems were also studied.The experimental results showed that the adsorption performance of both systems increased after doping with graphene oxide.Finally,the optimum doping ratio of graphene oxide was proposed according to the experimental results.