Biosorption of heavy metal ions on peel of Artocarpus nobilis fruit: 1Ni(II) sorption under static and dynamic conditions

The peel of the edible fruit, Artocarpus nobilis, a plant endemic to Sri Lanka, shows remarkable adsorption capabilities toward Ni(II), a heavy metal ion. Removal efficiency of 50% obtained with air-dried particles (0.710mm<1.0mm) of the above waste material under both static and dynamic conditions. It is enhanced to 71% after optimization of shaking time, settling time and processed temperature within a solution pH range of 4.0-7.0. Application of data on linearized Langmuir isotherm model shows a higher regression coefficient of 0.994, as compared to that of the Freundlich model, leading to the maximum adsorption capacity of 12,048mgkg(-1). The amount of biosorption of Ni(II) at equilibrium determined from the pseudo-first-order model is 2259mgkg(-1) which is in good agreement with the experimental value of 2348mgkg(-1). Removal efficiency further increases under dynamic conditions up to 93% by optimizing the packing bed height and flow rate. Application of dynamic adsorption models, namely Thomas, Adams-Bohart and Yoon-Nelson, shows attractive results with high regression coefficients. It is conclusively demonstrated that the peel of Artocarpus nobilis fruit can be used as an effective biosorbent for the removal of Ni(II) from wastewater.