Adsorptive Desulfurization by Copper Species within Confined Space

Abstract

Copper species were incorporated into SBA-15 by solid-state grinding precursor with as-prepared mesoporous silica (SPA). The obtained materials (CuAS) were well-characterized by XRD, TEM, N(2) adsorption, H(2)-TPR, IR, and TG and compared with the material derived from calcined SBA-15 (CuCS). Surprisingly, CuO up to 6.7 mmol·g(-1) can be highly dispersed on SBA-15 by use of SPA strategy. Such CuO forms a smooth layer coated on the internal walls of SBA-15, which contributes to the spatial order and results in less-blocked mesopores. However, the aggregation of CuO takes place in CuCS material containing 6.7 mmol·g(-1) copper, which generates large CuO particles of 21.4 nm outside the mesopores. We reveal that the high dispersion extent of CuO is ascribed to the abundant silanols, as well as the confined space between template and silica walls provided by as-prepared SBA-15. The SPA strategy allows template removal and precursor conversion in one step, avoids the repeated calcination in conventional modification process, and saves time and energy. We also demonstrate that the CuAS material after autoreduction exhibits much better adsorptive desulfurization capacity than CuCS. Moreover, the adsorption capacity of regenerated adsorbent can be recovered completely.

Synthesis of CuO/SBA-15 adsorbents for SOx removal applications, using different impregnation methods

“…This suggests that different copper species are formed during the impregnation, drying and calcination steps. Indeed, XRD analysis (not reported here) of the blue particles reveals the presence of crystalline CuO phase (PDF4+ 00-005-0661) while for the green ones, no peaks are observed suggesting either the formation of a very thin CuO film as reported by Tian et al [34] or the presence of copper species in strong interaction with the support, e.g., Cu-O-Si species [25,35]. Since all SBA-15 samples were impregnated under stirring and further homogenized by crushing before the drying and calcination steps, this heterogeneity must come from the drying and/or calcination steps.…”

Design and synthesis of W-containing mesoporous material with excellent catalytic activity for the oxidation of 4,6-DMDBT in fuels

“…Liu et al had designed and synthesized a series of mesoporous materials based on MCM-48 and SBA-15 and applied in the ADS systems successfully. [45][46][47][48][49] In addition, Dai and his group prepared FeCl 3 -SiO 2 with a foam-like mesoporous structure SiO 2 and used as catalyst, desulfurization efficiency could up to 98.4% under optimum conditions [50]. Our group synthesized a wormhole mesoporous structure catalyst, the removal of DBT reached 100% and the catalyst could recycled for 8 times with no significant decrease [35].…”

CuO/SBA-15 materials synthesized by solid state grinding: Influence of CuO dispersion and multicycle operation on DeSO performances

“…Wang et al reported an original impregnation method [42] consisting in grinding the as-synthesized SBA-15 material (still containing the surfactant in the porous network) with the copper precursor. Besides its simplicity and the fact that only one calcination step allows at the same time the removal of the organic template and the decomposition of the metal precursor, this method was reported to yield highly dispersed copper species in the mesoporous channels of the support [43][44][45][46][47][48]. For these reasons, such a method was used in the present work with a special emphasis on the influence of the calcination conditions.…”

“…According to the literature [47], it is possible that such a thermal treatment under nitrogen results in the reduction of the Cu 2+ copper species to Cu + species [58,59] which might be more active for the oxidation-chemisorption of SO 2 . This phenomenon is currently under investigation.…”