Photodegradation of acid red 114 dissolved using a photo-Fenton process with TiO2

Abstract

A dye acid red 114 (C.I. 23635) was photochemically removed by adding ferric ion (Fe3+), TiO2 particles, and H2O2 in the presence of the UV radiation. The removal rates of the acid red 114 (C.I. 23635) dye were 0.183, 0.210, and 0.233 mg/l/min when the concentrations of Fe3+ were 50, 100, and 130 mg/l. The removal rate of the dye increased from 0.173, through 0.200, 0.210 to 0.260 mg/l/min when the H2O2 concentrations were 10, 50, 100, and 150 mg/l, respectively. The removal rates were 0.200, 0.207, 0.210, 0.273, and 0.293 mg/l/min when the concentrations of TiO2 were 40, 60, 100, 500, and 1000 mg/l, respectively. The removal rate at pH 2.5 was higher than any other; pH 3.5, 5.5, and 8.5 and the photodegradation efficiency increased with the flow rate of air in the range from 1 to 10 l/min. From these results, relationships between the removal rate and the concentration of added Fe3+, H2O2, and TiO2 could be expressed as the following second-order equations, respectively, Rremoval=3×10−6 ×(CFe3+)2+5×10−5 ×(CFe3+)+0.1729; Rremoval=2×10−6 ×(CH2O2)2+2×10−3 ×(CH2O2)+0.1759; and Rremoval=−1×10−7 ×(CTiO2)2+2×10−4×(CTiO2)+0.1867.