Photocatalysis of 4-chlorophenol mediated by TiO2 fixed to concrete surfaces

Titanium dioxide (TiO2) powder was mixed with varying concrete sealer formulations and applied to prepared concrete surfaces within PVC batch reactors. A solution of 4-chlorophenol in de-ionized water, with an initial 4-chlorophenol concentration of 4 mg/L, was added to each open reactor. The photocatalytic efficiency of each TiO2-sealer was determined through bulk solution sampling while a reactor was exposed to continuous UV light. Through analysis of mean 4-chlorophenol concentrations, the disappearance of 4-chlorophenol from solution was attributed solely to the presence of TiO2 in the sealed concrete surface of a UV exposed reactor. The rate of disappearance increased when the mass percent of TiO2 in the sealer was increased. The zero-order reaction rate constants ranged from 0.135 to 0.2873 mg L−1 h−1.