COLOR AND COD REMOVAL FROM DYE CONTAINING WASTEWATER BY FENTON PROCESS AND COAGULATiON-FLOCCULATION

摘要

The purpose of the present study is to investigate the Fenton, Fenton under solar-light and coagulation-flocculation processes to remove color from dye solution containing Disperse Yellow 119. Experimental study was designed to obtain maximum color and COD removal at optimum coagulation conditions (pH and coagulant dose) and Fenton oxidation conditions (pH, temperature, oxidation time, solar irradiation time, FeSO_4and H_2O_2 doses).In coagulation experiments, FeSO_47H_2O, FeCI_36H_2O and AI_2(SO_4)_3.18H_2O reagents were used at varying dosages between 10-400 mgl"1. Fenton process experiments were carried out using varying hydrogen peroxide and FeSO_4 dosages at varying pH values in order to determine the optimum conditions for best COD and color removal. Fenton-solar light experiments were conducted by exposing directly to sun-light 200 ml dye solutions using glass vessels, 3.8 cm depth and 9.5 cm in diameter with an exposition area 71 cm~2 without stirring.For coagulation experiments, the maximum removals were 80% of COD, 99.9% of color at pH 6 for 75 mgl~-1 FeSO_4 dosage, 85% of COD, 99.9% of color at pH 6 for 100 mgl~-1 FeCI_3dosage, 91.7% of COD, 99.6% of color at pH 7 for 200 mgl"1 alum dosage, respectively. The Fenton experimental results showed that 99.7% color and 98.6% COD removals were proved at pH=3.0 , 30 °C temperature, 50 mgl~-1Fe~+2 and 75 mgl~-1 H_2O_2 , 15 min oxidation time. After 20 min of solar irradiation time during Fenton process the decolorization was 99.8 %. A COD reduction of about 97.5 % was observed at the same time.