The Use of Peanut Hull for the Adsorption of Colour from Aqueous Dye Solutions and Dye Textile Effluent

Peanut hull, an agricultural waste, proved to act as an efficient adsorbent for five anionic and cationic dyes. The process was found to be a pH dependent, suggesting the adsorption is controlled by interaction between the charged dye molecule and the surface charge on the adsorbent. The effect of variable parameters (contact time, pH, mass of adsorbent, dye concentration, agitation and activation by sulfuric acid) on the adsorption process was examined and optimum experimental conditions were established. The pH value of zero point of charge of the adsorbent was estimated and to be in the range of pH 4.5-5.5. The isothermal data for biosorption followed the Langmuir and Freundlich models and the different adsorption behaviour of basic and acidic dyes with respect to their structures is discussed.