Surface-functionalized mesoporous silica nanoparticles as sorbents for BTEX

A series of octyl-functionalized and surfactant-containing mesoporous silica nanoparticle (MSN) materials were synthesized via a co-condensation method. The authors investigated the feasibility of the MSN materials as adsorbents for BTEX (benzene, toluene, ethylbenzene, and xylenes) in groundwater. Octyl group functionalization up to 1.5 mol octyl/kg MSN improved BTEX adsorption capacity, while the mesoporous structure was still maintained. The following trend in adsorption equilibrium and kinetics of each BTEX compound onto MSN was observed: p-xylene > ethylbenzene > = toluene > benzene. Pseudo-second-order rate constant for p-xylene adsorption onto MSN was 0.907 g/mmol.min, significantly higher than that of activated carbon (0.043 g/mol.min). Desorption/regeneration with methanol was completed in 2 h, and the regenerated MSN showed the adsorption capability equivalent to the original. We envision that the MSN material could serve as an efficient adsorbent for the removal of BTEX from aqueous phase.