Application of chitosan for acid blue 92 removal by biosorption and coagulation - flocculation processes

Abstract

Azo dyes are often found in the environment as a result of their wide industrial uses. These industrial pollutants are common contaminants in wastewater and are difficult to decolourise due to their complex aromatic structure and synthetic origin. During the past three decades, several wastewater treatment methods have been reported and attempt for the removal of dyes from the textile effluents. This study is focused on the removal Acid Blue 92 (AB92), which is principally used in the textile industry. For this removal, it was applied two different techniques: the biosorption and the coagulation – flocculation. As biosorbent, chitosan was used due to its low cost, its wide intrinsic properties and its abundance. The first part of this work consisted of the study of the equilibrium conditions and the sorption kinetics of AB92 on chitosan. The effect of parameters such as the initial dye concentration, pH, sorbent dosage, etc. was also discussed. On the other hand, it carried out the coagulation – flocculation studies taking into account the critical parameters. Finally, several experiments were realized in order to know the influence of salts present in the effluents.