Low temperature preparation of anatase TiO2-coated activated carbon

Anatase titania sols were synthesized at low temperature (i.e. 75 °C) by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution. The prepared TiO2 nanoparticles were loaded on activated carbon in a rotatory evaporator under vacuum, and then the composite photocatalyst was employed for the removal of phenol from water. The apparent rate constant and quantum yield of the composite photocatalyst enhanced 5 and 2.5 times, respectively, compared to single phase titania. The activated carbon with strong adsorbent activity provided sites for the adsorption of phenol, and the adsorbed phenol migrated continuously onto the surface of TiO2 particles which were located mainly at the exterior surface of the activated carbon. Some phenol remained adsorbed on the catalyst when no traces of phenol were detected in the water. This adsorbed phenol could be degraded by illuminated titania while maintaining UV-irradiation. The photocatalyst was used for six cycles with degraded rate of phenol still higher than 80%.