Decolorization of a Simulated Reactive Textile Dyeing Effluent using a Plant-derived Coagulant

Abstract

The ability of a commercial tannin-based coagulant on the decolorization of a simulated textile effluent containing a reactive dye was studied in batch mode. For comparison, two conventional chemical coagulants (aluminum sulfate and Rifloc 6548-organic coagulant) were also tested. Preliminary assays suggested a higher performance of Tanfloc SG and Rifloc coagulants over the metal salt. Optimization assays conducted for Tanfloc SG, indicated a maximum color removal of 86.4%, recorded at a coagulant dosage of 240 mg/L and at pH 7. A decolorization efficiency of 42.4% was found for the optimized dosage of 144 mg/L at pH 9. At this condition, the treatment cost using Tanfloc was estimated as 0.21 EUR/m3, around twice the Rifloc when used at 96 mg/L, generating 81% of treatment efficiency. Rifloc outperformed Tanfloc, and its use also seemed to be more economical but may have negative impacts on the environment. However, Tanfloc still showed promising results and presented a better performance in terms of sedimentation velocity and floc size.