Selective removal of Sulfur and Nitrogen compounds from Model Feed: Synthesis, characterization and adsorption application of alumina-based adsorbents

A novel adsorbent based on a support + linker + π-acceptor formulation has been developed and applied for the direct selective removal of refractory heteroatoms (sulfur and nitrogen species) present in various oil feeds. Pristine mesoporous Al2O3 and 10wt.% TiO2-Al2O3 were synthesized and used as supports for immobilizing ethylenediamine (EDA) linker followed by the π-acceptor, 2, 7- Dinitro-9-fluorenone (DNF). The materials were characterized using BET, FTIR, TGA techniques to ascertain their physicochemical properties. From the adsorption studies using model compounds (thiophene and pyridine) in ultra-low sulfur diesel (ULSD) feedstock, the Al2O3-EDA-DNF (adsorbent A) showed 41.5% sulfur removal efficiency, whiles its 10 wt.% Al2O3-EDA-DNF (adsorbent B) counterpart gave 51.0% removal efficiency. For these adsorbents, no significant removal of nitrogen species was observed with the model feed; however, when the adsorbents A and B were used for adsorption of a pre-treated oil feed, different results were obtained. Adsorbent A successfully removed 85.7 % and 24.3% of the sulfur and nitrogen impurities, respectively, whereas adsorbent B removed 74.8% of the sulfur but negligible amounts of nitrogen species.  This successful removal can be attributed to the textural properties of the supports used for the synthesized adsorbents.

Author(s): Anakaren Botana

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