Decolorization of dyeing wastewater by chitosan from dried shrimp shell

Abstract

The possibility for removal of dyestuffs contaminant from an effluent by dried-shrimp shell chitosan adsorbent was investigated in batch and continuous modes. The chitosan was prepared in three forms such a flake, bead and crosslinked bead. Reactive dye RR 120 and acid dye AB 129 were chosen. Comparing ability of decolorization of chitosan in each from when concentration was 30 mg/l at pH 7, the results showed that the percentage of dyestuffs removal obtained from crosslinked chitosan bead was higher than that of non-crosslinked bead and flake forms, respectively. The experimental results also showed that the initial dye concentration and the pH of dyeing wastewater played an important role for decolorization. The removal of dye increased when decrease in pH or increase in initial dye concentration. All equilibrium isotherms could be well fitted by Langmuir equation. In the column studies, the results showed that the decolorization was strongly deepened on flow rate and bed height of packed column.