The comparative study on inhibitory effect of natural organic matters on the TiO and activated carbon/TiO composites for the removal of 17α-ethinylestradiol.

To reduce or eliminate the inhibition effect of natural organic matters (NOMs) in water on TiO photocatalysis for removal of emerging contaminants, four activated carbon/titanium dioxide (AC/TiO) composites with different pore structure were prepared by hydrothermal method. The results showed that anatase TiO particles were uniformly distributed in the pores or onto the surface of activated carbons. The total removal rate of 6 mg L 17α-ethinylestradiol (EE2) on the four AC/TiO composites reached above 90%, 30% higher than that of EE2 on TiO. The degradation rate constants of EE2 on four kinds of AC/TiO were much higher than that on TiO. Further study indicated that the adsorption removal ratio of EE2 on the composites was slightly reduced mainly because competitive adsorption between hydrophilic NOMs (HA and FA) and EE2 molecules when HA and FA coexisted with EE2 in water. But importantly, the obvious inhibitory effect of FA for TiO photocatalysis was eliminated on four composites because the introduction of AC with excellent adsorption capacity can preferentially transfer hydrophobic EE2 molecules onto adsorption sites of TiO/AC composites.