Mesoporous SiO2 was modified by grafting with NH2(CH2)(3)Si(OEt)(3) and used for adsorption of p-ClC6H4OH. The SiO2 samples were characterized by X-ray diffraction and N-2 sorption anal. Adsorption capacity of modified/unmodified SiO2 was detd. at 25 degrees C for p-ClC6H4OH concn. 5.0.10(-4)-4.2.10(-2) mol/L. More than 2.5 times higher adsorption capacity was achieved on modified SiO2.