Removal of dyes from aqueous solutions by cellulosic waste orange peel

The adsorption of dyes such as congo red, procion orange and rhodamine-B by waste orange peel was examined at different concentrations of dyes, adsorbent dosage, agitation time and pH. The adsorption obeyed both the Langmuir and Freundlich isotherms and the process of uptake followed first-order rate kinetics. Acidic pH was favourable for adsorption for all three dyes. Desorption studies showed that alkaline pH was efficient for desorption of all the dyes.