Influence of Impregnation Medium on the Adsorptive Performance of Silica Sulfuric Acid for the Removal of Gaseous o-Xylene: Comparison on Ethyl Acetate and Water

Silica supported sulfuric acid (SSA) has been demonstrated to be capable of effectively removing phenyl VOCs through the reaction-type adsorption mechanism. The effects of the solvent (water, ethyl acetate) used to impregnate silica gel with H2SO4 solution in order to prepare SSA adsorbents have been studied. As-prepared two series SSA(E)-x and SSA(W)-x materials (x = 1, 2, 3, 4) were characterized by TG, SEM/EDS and N-2 adsorption/desorption techniques, and their breakthrough adsorption performances were evaluated from experimental and theoretical aspects. The results showed that the H2SO4 loading amounts were 2.8, 4.0, 4.8 and 5.6 mmol g(-1) respectively for both SSA(E)-x and SSA(W)-x when x equaled 1, 2, 3, 4. Among them, SSA(E)-4 was found to have a higher proportion of the C-state H2SO4 than SSA(W)-4. Both SSA(E)-x and SSA(W)-x exhibited significant removal capacity of gaseous o-xylene. The reactive temperature regions were determined to be 120-170 degrees C for SSA(E)-4 and 120-160 degrees C for SSA(W)-4 with a common optimum point of 160 degrees C. Both SSA(E)-x and SSA(W)-x adsorbents exhibited excellent recyclability and reuse performance. Further, the series SSA(E)-x materials outperformed the series SSA(W)-x on all adsorption performance metrics, suggesting that ethyl acetate is a preferred solvent for preparing the SSA materials in phenyl VOCs removal application.

Automated summary

The effects of solvent type on the performance of silica supported sulfuric acid (SSA) adsorbents for removing phenyl VOCs were investigated. The results showed that adsorbents prepared using ethyl acetate solvent exhibited better performance.