Effectiveness of Aluminum Chlorohydrate (ACH) for Decolorization of Silk Dyebath Effluents

The present study focuses on the decolorization of real silk dyebath effluents using analytical-grade magnesium chloride (MCl) with and without guar gum (GG) as a coagulant aid and industrial-grade polyaluminium chloride (PACl) and aluminum chlorohydrate (ACH) as coagulants. A higher decolorization efficiency of 97% at a very high dosage of 1800 mg L-1 was observed for MCl. However, considering the purity, dosage, decolorization efficiency, and quantity and quality of sludge production, ACH was found to be the best coagulant, giving 91% decolorization efficiency at a dose of just 100 mg L-1. To achieve this high degree of decolorization efficiency, the dosage for PACl was found to be approximately 50% higher than that of ACH. Effective decolorization (>90%) at a very low dosage (100 mg L-1) and minimal quantity of sludge production by ACH demonstrate that ACH is an effective coagulant for decolorization of silk dyebath effluents.