EPR spectroscopy studies on surface reactivity of quartz

With the technique of Electron Paramagnetic Resonance Spectroscopy (EPR),we studied the surface reacivity of quartz on adsorbing Cut II) ions from aqueous solution over the pH range from 2 to 11. The surface sorption mass of Cut II), re,,is as a function of pH. The Cut II) surface coverage for powered quartz samples changes from 0 to 10.23 %. The EPR spectra can be demonstrated with the coexistence of several binding forms of Cut (II) ions on the surface,that is,(SO)(2)Cu at pH= 4.7,SOCu2+ at pH= 6.5,SOCu (OH)(4)(3)- at pH=7,and SOH ... Cu(OH)(2(s)) at pH= 10. Therefore, the sorption tendency that the Cu(II) ions are either adsorbed at isolate sites or form multinuclear complexes versus three-dimensional precipitates onto the surface of quartz is strongly dependent on the natures of quartz surface and aqueous solution medium.