Novel ZnO photocatalysts for pollutants' abatement under solar radiation at pilot plant scale

This study reports on the photocatalytic properties and efficiency of sol-gel ZnO powders, investigated at laboratory scale (1.32 L vessel reactor), under simulated solar radiation, in static regime and at pilot plant scale using Compound Parabolic Collector (CPC) photo-reactors (10 L), under solar radiation. The removal of phenol and imidacloprid in a concentration range of 1-50 mg/L was investigated. Optimal operating conditions were identified at laboratory scale and validated in the solar CPC photoreactors, as follows: the type of photocatalyst (ZnO annealed at 550 degrees C, Z550), the catalyst load (200 mg/L), the water matrix (natural water). Good photocatalytic efficiencies were recorded after 4 h of solar irradiation (Q(UV)similar to 25 kJ/L) in optimized conditions: 89 % for phenol and 92 % for imidacloprid at 5 mg/L initial pollutant concentration. Thus, the ZnO powder represents a promising photocatalyst able to remove traces of organic pollutants from wastewaters.