Preparation Of MOFs-derived Carbon-modified BN Materials And Their Adsorption And Desulfurization Performance

With the rapid development of the automotive vehicle industry,the demand for fuels has increased dramatically.There are a variety of sulfur compounds in untreated fuels,and the toxic sulfur oxides(SO_x)produced during the combustion can cause acid rain and haze,destroying the ecological environment and endangering human health.Therefore,stringent regulations have been adopted to restrict the sulfur content in fuels.Currently,hydrodesulfurization(HDS)is widely utilized in industry,but its disadvantages such as high operating conditions and lower removal efficiency for aromatic sulfur compounds make it difficult to meet increasingly stringent environmental regulations.The method of adsorption has attracted much attention in emerging desulfurization technologies because of its mild reaction conditions,low equipment investment,and high energy efficiency.The design and preparation of an ideal adsorbents with good chemical stability,high selectivity,excellent capacity and good reusability is the key to adsorptive desulfurization.Here,a variety of boron nitride(BN)-based adsorbents were designed and prepared by calcination method.The structural characterizations of the prepared adsorbents were carried out.The interaction between these adsorbents and the aromatic sulfur compounds in model fuels was studied and the adsorption mechanism was clarified.Firstly,a kind of BN/ZIF-8 derived carbon hybrid materials were designed and prepared,and the effects of calcination temperature and ZIF-8 content on the microstructure and adsorptive desulfurization performance of the adsorbent were investigated.The characterization of UV-Vis DRS,SEM,XPS showed that carbon atoms were doped into BN.As the calcination temperature increases,the impurity content of the BN/ZIF-8 derived carbon hybrid materials decreases,and the specific surface area increases.The results of adsorption experiments showed that the adsorptive performance of the prepared adsorbent for dibenzothiophene(DBT)gradually increased with the increase of the calcination temperature.The BN/ZIF-8 derived carbon hybrid material prepared at a calcination temperature of 950oC has the best adsorptive performance.At the temperature,with the increase of ZIF-8 content,the adsorptive capacity first increases and then decreases.When the content of ZIF-8 was 0.5 g,the adsorptive capacity of BN-C for DBT could reach up to 35.6 mg S/g.The adsorption mechanism was analyzed as the?-?interaction between BN-C,ZIF-8 derived carbon and aromatic sulfur compounds.In addition,the Lewis acid-base interaction between BN-C and aromatic sulfur compounds enhanced by carbon doping also plays a role.In order to further improve the adsorptive performance,Ce-MC@BN adsorbent doped with Ce and carbon atoms was prepared with Ce-MOFs,boric acid,and melamine as precursors.Its adsorptive desulfurization performance was studied.The characterizations of SEM,XRD,XPS showed that Ce was successfully doped into Ce-MC@BN.The results of static adsorption experiments showed that the adsorptive capacity of Ce-MC@BN for DBT is 48.0 mg S/g,and it has good adsorptive performance for 4-MDBT and 4,6-DMDBT.The superior adsorptive capacity of Ce-MC@BN may be due to the introduction of Ce species exposing more active sites,Lewis acid-base interaction and?-?interaction.