Studies on toluene adsorption performance and hydrophobic property in phenyl functionalized KIT-6

Phenyl functionalized KIT-6 materials were prepared by co-condensation one-step method. The phenyl modified sample preserved similar toluene adsorption capacity compared with pure KIT-6 at dry conditions. At high humidity environments, the sample exhibited higher toluene adsorption capacity and better selectivity. The value of Q_wet/Q_dry for the (1:6)KIT-6 (PTES/TEOS = 1:6) was nearly five times higher than that of pure KIT-6 (77.8% vs. 16.1%). Their excellent hydrophobic properties were due to the conjugated π-electrons effect between aromatic rings of phenyl groups and toluene molecules within the mesoporous channels. With increasing the percentage of PTES, the roll-up phenomena arising from the competitive adsorption of water and toluene were mitigated. Furthermore, we have calculated the rate constant using Yoon-Nelson model at dry conditions, and obtained the Henry constant from toluene or water adsorption isotherms. The results demonstrated that the phenyl modified KIT-6 had a better capture ability for toluene than the pure sample.