Selective removal of lead from aqueous solutions by ethylenediamine-modified attapulgite

The main objective of this work was to explore the feasibility of using ethylenediamine-modified attapulgite (EMATP) as the sorbent for lead removal from water. A novel amine-modified attapulgite was developed, and the structural and surface characteristics of the materials were investigated by N-2 sorption-desorption, Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction, zeta potential measurement, and X-ray photoelectron spectroscopy. The amine-modified attapulgite clay extracted from Xuyi, Jiangsu in China exhibited a higher sorption affinity for aqueous Pb(II) ions resulting from complexation of the metal ions by surface amino groups of the amine-modified attapulgite. Moreover, the sorption affinity for Pb(II) ions was not affected by the presence of and the alkali metal ions (Na(I)). In addition, ethylenediamine modified attapulgite (EMATP) also has good sorption capacity when incorporating other metal ions (Cu(II), Zn(II), Mn(II), Cd(II), Co(II), and Ni(II)). The sorption kinetic of Pb(II) was well described by the pseudo-second order kinetic equation while the sorption isotherm followed the Langmuir model. The lead loaded amine-modified attapulgite could be regenerated easily by acid treatment. Findings of the present work highlight the potential use of amine-modified attapulgite as an effective and recyclable sorbent for the selective removal of Pb(II) ions from water. (C) 2013 Elsevier B.V. All rights reserved.