Role of phosphorus in carbon matrix in desulfurization of diesel fuel using adsorption process

Abstract

Adsorptive removal of dibenzothiophene (DBT) and 4, from model diesel fuel with 20 ppmw total concentration of sulfur was investigated on polymerderived carbons with incorporated heteroatoms of oxygen, sulfur and phosphorus. The materials before and after exposure to model diesel fuel were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The results indicated that the presence of phosphorus, especially in the form of pyrophosphates and P 2 O 5 , increases the capacity and selectivity for removal of dibenzothiophenes. It also affects the adsorption mechanism. Phosphorus suppresses oxidation reactions of DBT and DMDBT. Owing to a possible location of bulky phosphorus groups in pore with sizes between 10-30 Å thiophenic molecules are strongly adsorbed there via dispersive forces. Acidic environment also enhances adsorption via acid-base interactions. Physical adsorption mechanism and stability of surface make these carbons attractive candidates for thermal regeneration.

Ordered mesoporous carbon CMK-5 as a potential sorbent for fuel desulfurization: Application to the removal of dibenzothiophene and comparison with CMK-3

“…Table 4 compares the capacity of several carbon adsorbents and some non-carbonaceous materials toward DBT adsorption. Of course, one has to take into account that the values have been obtained at different initial concentration of the sulfur compound, for which direct comparison is rather inappropriate (typically, the higher solution concentration, the higher adsorption capacity) [47]. However, different sulfur-adsorption capacities depend not only on the textural structure of the adsorbents but also on their surface functional groups as well as the presence of metallic species on the surface.…”

“…Relatively high adsorption capacities have been observed for the mesoporous carbons with highly dispersed transition metals which act as media for the reactive adsorption of DBT (Table 4) [49,50]. Recent studies by Seredych et al [18,32,47] have demonstrated that the presence of oxygen, sulfur and phosphorus species in the carbon matrix significantly increases their capacity and selectivity for removal of DBT. Also, as reported by An et al [57], treatment of the mesoporous carbons with suitable reagents such as ammonia significantly increases their adsorption capacity, which has been related to generation of micropores.…”

Functional monomer screening and preparation of dibenzothiophene-imprinted polymers on the surface of carbon microsphere

“…On the other hand, DBT and its alkyl derivatives are destructed and wasted. Therefore, searching an effective way for deep desulfurization without breaking sulfurcontaining molecules in fuels is urgently needed [2,3]. Traditional ways for desulfurization include hydrodesulfurization, oxidative desulfurization [4], adsorptive desulfurization [5][6][7], extractive desulfurization [8], and biodesulfurization [9,10].…”

Selective removal of dibenzothiophene from commercial diesel using manganese dioxide-modified activated carbon: a kinetic study

“…Adsorbents of pore diameter 0.7-1.0 nm are suitable for accessing DBT and other cyclic OSC, as the diameter of these compounds are comparable to the dimension of these adsorbents. [1,8] Larger pore diameter is also enhancing DBT and other cyclic OSC by reducing mass transfer resistance and hence increasing the rate of the process. As indicated in Table 1, pore diameter of AC has been reduced after surface modification; however, pore diameter of all adsorbents is larger than 0.7 nm, which is necessary for accessing BDT inside the adsorbent.…”

“…Emails: mohammad.algouti@qu.edu.qa; alghoutimohammad@gmail.com adsorbents has received great attention in the literature and promising results are reported in this area. [5][6][7][8] Zeolite loaded with Cu, Ni, Pd, Zn and Ce showed a high selectivity for BT and DBT removal from diesel. [6,7,9] Moreover, Cu-modified and Ag-modified zeolites were found efficient for reducing DBT in commercial diesel.…”