It is concluded that hydrophobic MCM-41 is a potential
adsorbent for the removal of VOCs present in high
concentrations and high humidity streams. Proper
modification of the pore openings of MCM-41 can
significantly enhance the adsorption performance without
a remarkable loss of the accessible pores. Hydrophobic
zeolites are candidate adsorbents in removing
VOCs in low concentrations with high humidity. A
composite adsorbent composed of hydrophobic microporous
zeolites and mesoporous molecular sieves,
such as hydrophobic zeolite Y plus MCM-41, may be
expected to be promising in VOC removal because it
could handle VOCs in a larger spectrum of concentrations
with high humidity. At the moment, activated
carbon adsorbents will still be the first choice for use
in air-flow treatment systems because they are costeffective
materials, although some of the above-mentioned
disadvantages are frequently encountered in
practice. However, MCM-41 will be a particularly
efficient and competitive adsorbent for VOC recovery
at high concentrations or for applications where lowtemperature
waste heat is available for regeneration.