Adsorption of Pb(II) by tourmaline-montmorillonite composite in aqueous phase

Abstract

In this study, a tourmaline-montmorillonite composite (TMMs) was synthesized by vacuum sintering to adsorb Pb(II) from aqueous phase. Different sintering temperature and proportion of tourmaline (TM) were first investigated by evaluating the adsorption capacity for Pb(II). The results indicated that the proper sintering temperature of the synthesis process and proportion of TM were 800 °C and 30.7% respectively. Batch experiments indicated Pseudo-second-order kinetic model and Freundlich adsorption isotherms fitted well with the adsorption characteristics of Pb(II) on TMMs, indicating that the adsorption progress of Pb(II) on TMMs related to chemical absorption and the maximum adsorption capacity was 303.21 mg/g. The background electrolyte concentration and solution pH have little effect on the adsorption behavior of TMMs. Adsorption mechanism of Pb(II) on TMMs might attribute to the electrostatic and complexation processes such as dissociation of metal ion bonds on the surface, hydroxylation on the surface of minerals, and self-polarization. The structure of TMMs was tested by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). This work provided a good reference for the application of tourmaline on treatment of heavy metals pollution in water.