Performance comparison of Fenton process, ferric coagulation and H2O2/pyridine/Cu(II) system for decolorization of Remazol Turquoise Blue G-133

Abstract

This paper evaluates the Fenton process (involving oxidation and coagulation), ferric coagulation and H2O2/pyridine/C(II) system for the removal of color from a synthetic textile wastewater containing polyvinyl alcohol and a reactive dyestuff, Remazol Turquoise Blue G-133. Experiments were conducted to investigate the effects of operating variables such as pH, coagulant dose, polyelectrolyte type, H2O2 and Fe(II) concentrations, optimum pyridine and Cu(II) dosages on decolorization efficiency. Optimal operating conditions were experimentally determined. A decolorization efficiency of 96% was possible to achieve with Fenton's reagent at an optimum [Fe(II)]:[H2O2] molar ratio of 1.21:1. However, 27% of initial Fe(II) was still in the effluent which required further treatment. Optimum pH and coagulant dose were found to be 7 and 100-125 mg l(-1), respectively, and the corresponding efficiency was similar to 100%. Cationic polyelectrolyte was found to be the most suitable type and 2 mg l(-1) of it enhanced the decolorization by 10% and 75% for filtered and nonfiltered samples, respectively. The maximum efficiency achieved by H2O2/Pyridine/Cu(II) system was about 92% with a high initial reaction rate different from the H2O2/pyridine system which also led to 92% removal. However, the required H2O2 dosage was very high in this system with a low CU(II). (c) 2006 Elsevier Ltd. All rights reserved.