Hierarchical Structure Porous Carbon Mateirals Applied In Adsorption Desulfurization Of Fuel Oil

In recent years, the environmental problems have attracted considerableattention and relevant policies have appeared in developed countries’ laws tocontrol the sulfur content in fuels to a reasonable level. Thus the study ofdesulfurization processing to reduce the sulfur content in fossil fuels seems to bemore and more important. It is well known that the traditional hydrodesulfurizationmethod shows huge energy consumption and poor performance to removethiophene and thiophene derivatives. However, adsorption desulfurization methodcould significantly enhance adsorption performance by a variety of approaches,like using various adsorbents or further modifying these adsorbents. The currentresearches in this area have focused on designing and synthesizing adsorbentmaterials with large specific surface area and superior porosity. Generally,molecule diffusion in micropores of block porous solid materials is considered tobe the main limiting step for adsorption process. Hence, it is necessary tosynthesize adsorbents with hierarchical structure such as porous carbonnanospheres and macro-mesoporous composite carbon materials, which caneffectively shorten diffusion distance and immensely accelerate adsorption rate. Inthis dissertation, hierarchical porous carbon adsorbent has been used as the startingmaterial to prepare a series of porous carbon adsorbent materials with high specificarea and hierarchical structure via different synthetic strategies. The obtainedmaterials were characterized by SEM, TEM, N2adsorption/desorption techniqueand so on. Their adsorption performance was also investigated by adsorbingdibenzothiophene which existed extensively in fuels. The detailed works weresummarized as follows:1. Porous carbon materials were prepared using soluble phenolic resin as carbonsource and MgO nanospheres as hard template. After KOH-activation (KOH/Cmass ratio=4:1), the macro/mesoporous carbon composite materials with large specific surface area (1502.7m2g-1) and pore volume (1.05cm3g-1) were finallyobtained. As an adsorbent, it displayed excellent adsorptive performance to adsorbDBT. It could reach equilibrium adsorption within10minutes and the kinetic datafollows closely to the model of pseudo-second-order. The maximum adsorptioncapacity was153.6mg g-1.2. Carbon nanospheres were successfully fabricated through a low temperaturehydrothermal process, in which glucose was used as carbon source. Then theywere activated by ZnCl2with ZnCl2/C mass ratio of4:1. The obtained hierarchicalcarbon nanospheres possessed ultrahigh specific surface area (3050.8m2g-1) andpore volume. When adsorbing DBT, it could reach the equilibrium adsorptionwithin30minutes with a maximum adsorption capacity of121mg g-1. The kineticdata follows closely to the model of pseudo-second-order and the experimentaldata of equilibrium adsorption capacity well matched Freundlich isotherms.3. Resorcinol formaldehyde (RF) resin spheres were synthesized by usingformaldehyde and resorcinol. After ZnCl2-activation process the hierarchical RFcarbon nanospheres with high specific surface area (2839.7m2g-1) and porevolume were obtained. The adsorbent could achieve equilibrium adsorption within10minutes in DBT aqueous solution. The kinetic data follows closely to the modelof pseudo-second-order and the experimental data of equilibrium adsorptioncapacity well matched Langmuir isotherms. The maximum adsorption capacitycould reach220mg g-1.