Application of Pomegranate Peel Waste on Biosorption of Methylene Blue from Aqueous Solutions

Pomegranate peel waste (PPW), a solid waste, was prepared and tested as biosorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solutions by batch procedure. The effects of pH of solution, biosorbent dosage, contact time, and dye initial concentration on biosorption capacity were studied. MB uptake was favorable at pHs ranging from 5.0 to 12.0. The contact time required to obtain the maximum biosorption was 5 h at 25 C using 0.6 g of biosorbent. Two kinetic equations models, pseudo-first-order and pseudo-secondorder, were used to study the mechanism of dye biosorption. The pseudo-second-order kinetic model should better explain the biosorption process of MB taken up by PPW biosorbent. MB biosorption onto PPW was analyzed by Langmuir, Freundlich, and Sips isotherm models. The best data were fitted to Sips isotherm model. It was found that the Sips model is appropriate to explain the biosorption isotherm. The maximum amount of MB biosorbed on PPW was 68.42 mg dye g -1 at 25 C. The results in this study indicated that PPW, is an attractive candidate for removing MB from aqueous solutions.