Study On Preparation And Properties Of Desulfurization Adsorbent Based On UiO-66

Fuels contain many different sulfur compounds.Sulfur is converted into SOx during combustion and discharged directly into the atmosphere,which is one of the main cause of acid rain and catalyst poisoning.Currently,clean fuel research has become an important topic in global environmental research,producing sulfur-free fuels that provide a cleaner and healthier ecosystem.Environmental regulations and governments in many countries require the production of transportation fuels that contain less sulfur.The operating conditions of traditional hydrodesulfurization technology are too harsh,it is difficult to meet ultra-low emission standards,and new deep desulfurization technology is urgently requried.Adsorption desulfurization can be used for deep desulfurization,which has the advantages of high adsorption capacity,high selectivity,simple regeneration path and no loss of octane number,and has been widely studied.According to the literatures reported,the adsorption capacity of complex adsorbent is larger than physical adsorption,regeneration is easier than that of chemical adsorption,and the adsorption activity of copper ion is better than other transition metals(silver,nickel,zinc,etc.),and the site of copper(?)has the advantages of non-toxicity,high efficiency and low cost.Metal organic frameworks(MOFs)have the advantages of large specific surface area,regular pore structure,and tailorble properties.The application of copper(?)loading and MOFs in adsorption separation is of potential value.Traditionally,the conversion of loaded copper(?)to copper(?)is formed by high temperature auto-reduction(HTA)in inert gas.However,for the thermal stability of most MOFs,it will cause skeleton collapse at high temperature,which limits the application of MOFs.The yield of copper(?)formed by high temperature auto-reduction method is also low.In this paper,the metal organic framework UiO-66(Zr)was synthesized by hydrothermal method,and the sulfonic acid group-SO3H functional group was introduced to prepare UiO-66-SO3H with different sulfonic acid group content.UiO-66-SO3CU was prepared by ion exchange method.Then,according to the weak reductive property of alcohols,the alcohol vapor interacts with Cu(?)at a relatively low temperature,and Cu(?)is reduced to Cu(?)to obtain UiO-66-SO3Cu(?)adsorbent.The modified adsorbent still has a crystal structure of UiO-66 by XRD analysis.XPS analysis showed that Cu(?)was successfully reduced to Cu(?)by steam induction.Through the image analysis of EDX elements,Cu(?)is uniformly distributed in the material.The desulfurization performance of the adsorbent was tested by adsorption desulfurization experiments.The results show that the adsorption desulfurization performance of UiO-66-SO3Cu(?)is the best when the proportion of sulfonic acid groups is 0.15.The order of desulfurization effect is:UiO-66-SO3Cu(?)-0.15>UiO-66>UiO-66-SO3Cu(?)-0.20>UiO-66-SO3Cu(?)-0.10>UiO-66-SO3Cu(?)-0.05.The material H-UiO-66-SO3H was successfully synthesized by introducing the template precursor,and H-UiO-66-SO3Cu was prepared by ion exchange.The porous adsorbent H-UiO-66-SO3Cu(?)was prepared by steam induction.A new mesoporous structure formed for H-UiO-66-SO3Cu(?)by BET and TEM analysis.The adsorption experiment showed that the ratio of templating agent was 0.3 and the proportion of sulfonic acid group was 0.225.The adsorption of thiophene(TP)by adsorbent was the best.The order of adsorption capacity was H-UiO-66-SO3Cu(?)-0.225>H-UiO-66-SO3Cu(?)-0.150>H-UiO-66-SO3Cu(?)-0.075>UiO-66.When the proportion of sulfonic acid groups is 0.150,the adsorption performance for benzothiophene(BT)is the best among these samples.The order of adsorption capacity was H-UiO-66-SO3Cu(?)-0.150>H-UiO-66-SO3Cu(?)-0.225>H-UiO-66-SO3Cu(?)-0.075>UiO-66.In order to make the adsorbent more efficient recovery,magnetic Fe3O4 nanoparticles were introduced into the UiO-66,and the Fe3O4@UiO-66 magnetic composite was successfully prepared and used to adsorb the thiophene sulfide in the model fuel.The samples were characterized by XRD,FT-IR,TEM and SEM,and their adsorptive desulfurization performance was investigated.The adsorption isotherm of TP adsorption on Fe3O4@UiO-66 composites was obtained by static adsorption experiments,which indicated that the composites have good adsorption capacity for thiophene in fuel oil,and the adsorption effect is similar to that of UiO-66.The use of an external magnetic field allows the adsorbent to be separated simply,quickly and efficiently.The results of the regenerative adsorption test showed that the regeneration performance of the adsorbent was good,and the adsorption amount decreased by 11%after 4 regenerations.