Adsorptivity of a Hyper Cross-Linked Ionic Polymer Poly(vinyl imidazole)-1,4-bis(chloromethyl)benzene for Thiophenic Sulfurs in Model Oil

A hyper cross-linked ionic polymer (HCIP) PVimBCmBn was synthesized through free radical polymerization of 1-vinylimidazole (Vim) and quaternized cross-linking with 1,4-bis(chloromethyl) benzene (BCmBn). Its composition, structure, morphology, specific area, porous structure and thermal stability were characterized, and the desulfurization performance was investigated. The results show that the HCIP prepared with stoichiometric ratio of PVim and BCmBn are ultrafine powders with specific area of 99.6 m2·g–1 and average pore size of 16.1 nm, being micro/mesoporous materials. The S-removability of HCIP is superior to its precursor (ethyl imidazole) and the imidazolium-based ionic liquids (ILs), which manifests the importance of the available micropores for the accommodation of sulfur molecules with less energy barrier. The adsorption isotherms of PVimBCmBn follow the Langmuir equation with its saturated adsorbance being 7.0, 5.2, and 4.1 mgS·g–1, respectively, for dibenzothiophene, benzothiophene, and thiophene in model oil at 293 K. However, its adsorptive removal ability for DBT in diesel oil is quite low due to its limited S-selectivity with respect to the abundant confused ring aromatics wherein.