Novel macroporous 3D photocatalytic foams for simultaneous wastewater disinfection and removal of contaminants of emerging concern

A comparative study of the photocatalytic efficiency obtained in water disinfection and the simultaneous removal of micropollutants was carried out by using three different TiO2 photocatalytic materials. The three photocatalysts were immobilized in macroporous reticulated ZrO2 3D foams and their efficiency was compared with that obtained in suspensions for the treatment of synthetic and real wastewater. The results obtained show similar photocatalytic efficiencies for the three photocatalysts used, showing the catalysts WTT-P and AQ1 to be an alternative to the common use of P25 catalyst. The use of supported photocatalysts in the treatment of synthetic water showed lower efficiencies compared to the suspended photocatalysts due to the existence of diffusive limitations caused by the low concentration of the micropollutants. However, these differences were not observed when treating a wastewater treatment effluent. In this case, the non-selective action of the hydroxyl radicals causes the loss of a significant part of the available radicals for the oxidation of non-target compounds present in the water. Consequently, diffusion was not identified as the limiting stage of the removal rate, but the availability of hydroxyl radicals in the reaction medium, which allows the 3D foams to be as effective as the processes in suspension.