Removal of Reactive Red 141 and Disperse Red 13 Dyes from Aqueous Solutions Using Different Coagulants: An Optimization and Comparison Study

Abstract

This study investigated the performance of different coagulants for the removal of different dye types from synthetic dye solutions. The ability to use each of the following: aluminium sulphate (Al2(SO4)3, aluminium chloride (AlCl3), and ferric chloride (FeCl3) as chemical coagulants were examined for removing reactive red 141 (RR 141) dye and disperse red 13 (DR 13) from dye solution. Coagulation studies determined the optimum pH, mixing time, coagulant dosages, and initial dye concentrations. The maximum efficiency for removing RR 141 was 65.7% by aluminium chloride at the operation condition of pH 8, mixing time 10 min, and dye concentration of 100 mg/L. In contrast, under the same conditions, ferric chloride could remove more than 98% of DR 13. Since the disperse dye type has better colour removal, the maximum volume of sludge was 0.3 kg/m3 which was produced when FeCl3 was used as a coagulant. The results demonstrated that coagulation is a promising technology for dye removal, especially for dispersed dyes as it has some characteristics such as colloidal dispersion and very low water solubility.