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应用XPS技术研究了不同pH条件下针铁矿表面磷的配位形式及转化特点。结果表明:磷浓度一定时,低pH值有利于形成磷的单基配位,高pH值有利于形成磷的双基配位。体系pH值升高,针铁矿表面的单基配位磷即较快地向双基配位磷转化;pH降低,双基配位磷则缓慢地向单基配位磷转化.分析认为,体系pH通过影响溶液中磷酸根的离子类型来影响针铁矿表面吸附磷的配位形式,pH变化引起表面磷酸根质子的解离和缔合,是导致针铁矿表面磷配位形式转变的重要原因。双基配位磷的稳定性比单基配位磷的高,原因在于两种表面配合物的键能和结构不同。
XPS was used to study the coordination forms and transformation characteristics of phosphorus on goethite surface under different pH conditions. The results show that when the concentration of phosphorus is low, the low pH value is conducive to the formation of single coordination of phosphorus, and the high pH is favorable for the formation of bismuth coordination of phosphorus. When the pH value of the system increased, the mononuclear coordination phosphorus on the surface of goethite rapidly converted to bidentate phosphorus. When the pH decreased, the bismuth coordination phosphorus slowly converted to mononuclear coordination phosphorus. The results showed that the pH of the system affected the type of phosphate adsorbed on the surface of goethite by influencing the type of phosphate in the solution. The change of pH caused the dissociation and association of the surface phosphate proton. The important reason for the change of form. The stability of bidentate phosphorus is higher than that of mononuclear coordination phosphorus due to the different bond energies and structures of the two surface complexes.