Investigation of the synergistic effect of hydrogen peroxide and ultrasound on the photocatalytic treatment under visible light of dyes wastewater

A photocatalytic process under visible light irradiation (LED lamp 13 W) assisted by ultrasound and hydrogen peroxide was investigated, aiming at enhancing the hydroxyl radical production compared to simple photocatalysis. Several parameters, including ultrasound power and H2O2 concentration, were investigated in the degradation of Rhodamine B. Fe doped TiO2 synthesized by the solid-state method was used as the photocatalyst. The synergistic effects between photocatalysis, ultrasound, and H2O2 were studied, and the absence of synergy between photocatalysis and ultrasound was demonstrated. Instead, a synergistic effect was observed between photocatalysis and hydrogen peroxide addition, in fact, the combination of photocatalysis with H2O2 was demonstrated to totally remove the Rhodamine B (5 ppm) in 2 hours, as contaminant removal was greater (by 50 %) when the two treatments were used simultaneously than the removal observed in the individual treatments, attributable to the Fenton reaction that promoted the hydroxyl radicals production.