Application research of hydrophobic silica in the recovery of oil vapor

The adsorption characteristics and porous structure of self-made hydrophobic silica (HS) used in the recovery of oil vapor were investigated using the methods of N₂ (g) adsorption measurement and SEM photograph, together with the pillared activated carbon (PAC). HS is a typical mesoporous material and has smaller surface area and bigger average pore diameter compared with the PAC. PAC has the well-developed interstitial structure, while HS´s surface holes are shallow. The structural difference between the two adsorbents determined the different adsorption/desorption performance in recovery of oil vapor. PAC has the bigger adsorption amount and faster adsorption rate of oil vapor, while the oil vapor adsorbed in HS is much easier to be desorbed. The mixture of PAC and HS represented both the properties of fast adsorption rate and perfect desorption performance which can improve the life and efficiency of the recovery system at the same time. The adsorption amount of adsorbent increased with the increase of inlet concentration and decreased with the increase of inlet velocity of oil vapor.