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

Abstract In this work, magnetic Fe 2 O 3 /TiO 2 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, H 2 O 2 concentration, pollutant concentration and treatment time were also investigated. The optimal pH value (pH 3), H 2 O 2 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 Fe 2 O 3 /TiO 2 monoliths showed remarkable photocatalytic activity as compared to Fe 2 O 3 and TiO 2 monoliths. This is attributed to the fact that TiO 2 combined with Fe 2 O 3 leads to the effective separation of photo excited carriers which result better degradation efficiency. The kinetics of RbX and fipronil degradation by supported Fe 2 O 3 /TiO 2 monoliths followed the first-order mechanism. Moreover, synthesized monoliths showed excellent stability and reusability for four cycles of degradation. In addition, the monolithic Fe 2 O 3 /TiO 2 photo-catalyst can be easier to recover after the treatment process which is more relevant to the practical application point of view.