Removable Pb (II) from aqueous solutions by adsorption onto natural and modified leonardite

Abstract

Natural leonardite was modified with manganese nitrate. The chemical composition, physical properties and adsorption efficient of natural and modified leonardite were investigated. The chemical composition was characterized by X–ray fluorescence spectroscopy (XRF) and energy dispersive X–ray spectrometry (EDXS). Physical properties, morphology and surface area were investigated by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller analyzer (BET). The adsorptions of Pb(II) onto natural and modified leonardite was determined by atomic absorption spectroscopy (AAS). The results of XRF and EDXS were showed that silicon was major element. The surface area of natural leonardite was 22.90 m²·g^–1 which less that the surface area of modified leonardite, 31.02 m²·g^–1. The Pb(II) adsorption data of natural and modified leonardite was fit well with the Langmuir isotherm equation. The maximum monolayer adsorption capacity of Pb(II) onto natural and modified leonardite was found to be 3.098 mg·g^–1 and 7.062 mg·g^–1 respectively. It was presented that the percentage of maximum adsorption capacity increase to 127.95.