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

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, R-removal = 3 x 10(-6) x (CFe3+)(2) + 5 x 10(-5) x (C-Fe(3+)) + 0.1729; R-removal = 2 x 10(-6) x (C-H2O2)2 + 2 x 10(-3) x (C-H2O2) + 0.1759; and R-removal = -1 x 10(-7) x (C-TiO2)(2) 2 x 10(-4) x (C-TiO2) + 0. 1867. (C) 2002 Published by Elsevier Science Ltd.