Removal of direct red and acid brilliant blue by adsorption on to banana pith

The adsorption of direct red and acid brilliant blue by waste banana pith was investigated by varying the agitation time, dye concentration, adsorbent dose and pH. The adsorption followed both Langmuir and Freundlich isotherms. The adsorption capacity was 5•92 and 4•42 mg dye per gram of the adsorbent for direct red and acid brilliant blue, respectively. Adsorption of dye followed first-order kinetics. An acidic pH was favourable for the adsorption of both dyes. An alkaline pH was favourable for desorption of the dyes.