bility due to the high concentration of polar oxygen atom in the molecule. It is a general consensus that the hydrophilic surface is prerequisite for the effective adsorption of hydrophilic adsorbate. Li et al. compared MTBE adsorption onto ACFs with different surface properties and concluded that the ACFs with oxygen and nitro- gen content of 2–3 mmol g−1 are most effective for the adsorption of hydrophilic MTBE [9]. XPS results showed that surface oxygen content of the postcrosslinked polymer was 4.3 wt.%, correspond- ing to 2.7 mmol g−1 . In contrast, the surface oxygen content of the nonpolar porous polymer was not determinable. Therefore, it can be concluded that the higher MTBE adsorption capability of the postcrosslinked polymer is attributed to its higher surface hydrophilicity compared to the hydrophobic nonpolar porous poly- mer. This conclusion is further supported by the results of MTBE adsorption over the chloromethylated polymer. For the nonpolar porous polymer and chloromethylated polymer, MTBE adsorption over the adsorbents followed Langmuir adsorption model and the adsorption parameter b in Langmuir adsorption model is char- acteristic of the affinity of the adsorbate to the adsorption sites on the surface of the adsorbent. The adsorption parameter b of the chloromethylated polymer and nonpolar porous polymer were 0.118 and 0.076, respectively, indicative of the stronger adsorption of MTBE onto the chloromethylated polymer although the adsorp- tion capacity of the chloromethylated polymer is lower than the nonpolar porous polymer. It is noteworthy that the surface oxygen content of the chloromethylated polymer was 2.6 wt.%, higher than that of the nonpolar porous polymer. This also clearly points out that MTBE tends to be adsorbed by more hydrophilic surface.