Synthesis And Adsorption Desulfurization Performance Of Porous Materials Based On Chromium Terephthalate

Chromium terephthalate porous materials have potential applications in many fields due to their high specific surface areas and abundant pore structures such as MIL-53(Cr)and MIL-101(Cr).However,at present,the synthesis method of such materials needs to be carried out under high temperature hydrothermal conditions,which inevitably leads to problems of high energy consumption and difficulty in handling the reaction equipment.Therefore,the synthesis of chromium terephthalate porous material at low temperature is a challenging research work.In addition,the adsorption desulfurization(ADS)of fuel attracts the researchers’ attention because of its low energy consumption and easy operation.Therefore,the development of new fuel desulfurization adsorbents is a hot research topic.In view of above problems,this thesis explores the synthesis of chromium terephthalate porous materials under low temperature conditions,and modified it based on MIL-53(Cr)with excellent adsorption and desulfurization performance.The adsorption and desulfurization performance of modified MIL-53(Cr)is as follows:Firstly,the synthesis of chromium terephthalate porous materials under low temperature conditions was explored.Under the synthesis system,the effects of parameters such as synthesis temperature,synthesis time,molar ratio of raw materials,pH value of the solution on the properties of the obtained materials were investigated.The results show that a new chromium-terephthalate porous material Cr-BDC-LT with lower crystallinity can be prepared by optimization of synthesis conditions.Due to the low order of the Cr-BDC-LT structure,it can expose a rich metal catalytic active site.Therefore,Cr-BDC-LT exhibits a superior catalytic performance in the oxidation reaction of cyclohexene compared with MIL-53(Cr)and MIL-101(Cr).Secondly,the adsorptive desulfurization performance of three kinds of chromium terephthalate porous materials in simulated fuel oil was evaluated.The results show that MIL-53(Cr)exhibits superior adsorption desulfurization performance.In order to further improve its performance,we attempt to introduce different metal as adsorption sites in MIL-53(Cr)materials.The results show that silver is the most effective loading metals for further enhancing the adsorption desulfurization performance of MIL-53(Cr).Then,based on the Ag loaded MIL-53(Cr)materials,the effects of parameters such as solvent,load concentration,calcination time,different initial sulfur content and sulfur-containing molecules on the adsorption and desulfurization performance of MIL-53(Cr)were investigated systematically.Adsorbent in the case of ethanol as solvent,Ag to Cr atomic ratio of 0.12,and air calcination at 300 °C for 6 h performed the best effect of DBT adsorption.Silver-supported MIL-53(Cr)performs a superior DBT adsorption desulfurization properties(94.2 mgS/g)using ADS method due to the π interaction of silver with sulfide which is higher than the reported MIL-53(Cr)with the adsorption performance of 86.4 mgS/g.Finally,for the regeneration of MIL-53(Cr)-Ag after adsorption of DBT,the regeneration method of MIL-53(Cr)-Ag adsorbent was explored.It was found that high temperature calcination is an effective regeneration method.After 5 times of repeated use of the adsorbent by the high temperature method,the adsorption amount can still reach 90 mgS/g,indicating that the material can be recycled and has potential industrial application prospects.