Assessment of chemically modified sugarcane bagasse for lead adsorption from aqueous medium

This study evaluated the adsorption capacity of chemically modified sugarcane bagasse with citric acid (B-CA), sodium hydroxide (B-S) and citric acid and sodium hydroxide (B-CAS) for Pb2+ ion adsorption in aqueous medium. Infrared spectroscopy (FT-IR) was used to characterise the materials, where the chemical modification was confirmed by the presence of carboxylate groups created at 1,730 cm(-1) peak. All assays related to Pb2+ ion adsorption onto adsorbent, i.e. equilibrium time between Pb2+ ions and adsorbate (24 h), as well as Pb2+ ion concentration, were performed in batch system. The initial and final Pb2+ ion concentration after shaking time was determined by Flame Atomic Absorption Spectrometry (FAAS). Isotherm adsorptions were applied to Langmuir and Freundlich linear models and maximum adsorption capacity (MAC) of materials towards Pb2+ ions was calculated in function of modifications. A significant improvement regarding Pb2+ ion adsorption after the bagasse treatment with citric acid, in which MAC was 52.63 mg g(-1), was observed. The adsorptions followed the behaviour described by the Langmuir linear model and its kinetics follow the behaviour described by the pseudo-second-order equation.