Biosorption of Pb(II) from aqueous solution using modified wheat straw

Abstract

The objective of this study was to convert wheat straw to metal ion adsorbent for waste water treatment. Ground wheat straw particles were modified with 0.5M citric acid to activate its natural adsorption capacity. The biosorption characteristics of Pb(II) onto modified wheat straw (MWS) gel, were evaluated as a function of pH, time, biomass dosage, initial concentration and temperature. Within the pH range studied (1.5-5.0), the optimal pH value suitable for the uptaking of Pb(II) was estimated at pH 5.0. Different models are used to fit experimental data and it indicates that the adsorption process follows Langmuir model and pseudo-second-order model. The maximum adsorption capacity obtained from the Langmuir model is 0.18mol kg ^-1 for the prepared sorbent. Equilibrium time is attained at 5-10min for the studied Pb(II) ion concentrations. The present study verified that such-modified wheat straw can be used as an effective and low-cost biosorbent for removal of Pb(II) from aqueous solution.