石英矿物表面反应性的EPR谱学研究

EPR Spectroscopy Studies on Surface Reactivity of Quartz

采用顺磁共振谱 (EPR)方法对不同 p H值条件下石英表面与 Cu2 + 离子反应的机理进行研究。当溶液的 p H值在 2至 11之间变化时 ,石英表面 Cu2 +离子的吸附覆盖率相应地由 0至 10 .32 %变化 ;同时 ,其EPR谱的线形、线宽及 g因子值也发生了特征的变化。研究表明 ,随着石英表面 Cu2 + 离子的吸附覆盖率的不断升高 ,表面反应产物的结合形态相应地出现单核化合物、多核化合物直至表面沉淀。

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