Studies on the effect of the chlorine content of chlorophenols(CPs)on their adsorption from aqueous solution by mesoporous SBA-15are important in understanding the mechanisms of CP adsorption.In this study,three CPs with different degrees of chlorine content(i.e.,2-chlorophenol,2,6-dichlorophenol and 2,4,6-trichlorophenol)were investigated.The effects of parameters such as temperature and solution pH were studied.The results showed that CP adsorption by SBA-15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH.Thermodynamic parameters such as Gibbs free energy change(ΔG0),enthalpy change(ΔH0)and entropy change(ΔS0)were also calculated.By comparison of the adsorption coefficient of CPs with varying physical-chemical properties(size,hydrophobicity and electron density),we propose that hydrophobic interactions between CPs and the SBA-15 surface,as well as electron donor-acceptor(EDA)complexes between oxygen of the siloxane surface of SBA-15(e--donor)and the π-system of the CPs(e--acceptor),were dominant adsorption mechanisms.