The huge use of large amount of dyes by textile industries generates substantial pollution, especially color which is difficult to be eliminated by conventional processes. The objective of this study was to investigate the removal of Acid Red 18 (AR18) in aqueous solution and in real textile effluent through coagulation/flocculation combined with adsorption on granular activated carbon (GAC). A series of jar test experiments were carried out using different doses of the textile coagulant HYDRODEC 5D and flocculent CHTT Floc to define the optimal conditions allowing a higher removal of color. Maximum color removal reached was 23% corresponding to an ABS(λ 508nm) = 1.23, under the following optimal conditions of coagulation-flocculation treatment: pH=9, coagulant dose of HIDRODEC= 35 ml.L-1 and a flocculent dose of CHTT Floc =55 ml.L-1. To improve water quality in terms of color, we applied a post treatment by adsorption on different quantities of GAC (1, 2, 3 and 4 g.L-1) where a high efficiency of color elimination was obtained. To confirm our experimental results, same study was conducted on a real textile effluent. Unexpectedly, results showed that coagulation/flocculation alone was sufficient to remove (AR18) color, DCO and turbidity.
R. Ben Dassi, B. Chamam, I. Trabelsi
Acid Red 18, Real textile effluent, Coagulation-floculation, Adsorption, GAC.