Synthesis of Fe2O3/TiO2 monoliths for the enhanced degradation of industrial dye and pesticide via photo-Fenton catalysis

In this work, magnetic Fe2O3/TiO2 monoliths were successfully synthesized through nanocasting method followed by wet impregnation for the removal of remazol brilliant red X-3BS (RbX) dye and widely used pesticide (Fipronil). The activity of such catalyst combined with the photo-Fenton catalysis was assayed under the UV light irradiation. The effect of various parameters such as pH, catalyst dosage, H2O2 concentration, pollutant concentration and treatment time were also investigated. The optimal pH value (pH 3), H2O2 concentration (60 mM) and catalyst dosage (2 g/L) leads the higher degradation efficiency of RbX (90.57%) within 180 min time. Whereas, it has been found that fipronil exhibited highest degradation efficiency of 88.71% at pH 3 using 10 mM of H(2)O(2 )concentration, 1.5 g/L of the catalyst in 120 min time. The Fe2O3/TiO2 monoliths showed remarkable photocatalytic activity as compared to Fe2O3 and TiO2 monoliths. This is attributed to the fact that TiO2 combined with Fe2O3 leads to the effective separation of photo excited carriers which result better degradation efficiency. The kinetics of RbX and fipronil degradation by supported Fe2O3/TiO2 monoliths followed the first-order mechanism. Moreover, synthesized monoliths showed excellent stability and reusability for four cycles of degradation. In addition, the monolithic Fe2O3/TiO2 photo-catalyst can be easier to recover after the treatment process which is more relevant to the practical application point of view.