Elucidation of lead ions adsorption mechanism on marmatite surface by PCA-assisted ToF-SIMS, XPS and zeta potential

摘要

The species on the lead-adsorbed marmatite surface at pH 3.0, 6.5 and 11 were studied by principal component analysis (PCA) assisted time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), zeta potential and Eh-pH diagram analysis. The interaction mechanism between lead ions and marmatite surface was also discussed. The results showed that Pb-O-Zn/Pb-O-Fe containing species and Pb-S containing species were major and minor lead-containing species on the lead-adsorbed marmatite surface at pH 3 and pH 6.5, respectively, while those at pH 11 were lead oxides/hydroxides and Pb-O-Zn/Pb-O-Fe containing species, respectively. The form of sulfur-containing species and oxygen-containing species on the lead-adsorbed marmatite surface is strongly pH-dependent. These results help to address the long-standing controversy regarding the products and mechanisms of lead ions adsorption on marmatite surface.