不同pH条件下针铁矿表面磷的配位形式及转化特点

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－定时，低ｐＨ值有利于形成克的单基配位，高ｐＨ值有利于形成磷的双基配位。体系ｐ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系子的解离和缔合，是导致针铁矿表

COORDINATION FORMS AND TRANSFORMATIONS OF PHOSPHATE ADSORBED BY GOETHITE SURFACE ON DIFFERENT pH

X-ray photoelectron spectroscopy (XPS) technique was used to study the coordination forms and transformation characteristics of P on goethite surfaces at different pH. The results showed that the chemical forms of P on goethite surfaces changed from the dominance of monoradical ligands to that of biradical ones with increasing pH of the solutions. For a given P concentration, increasing the pH of suspension could cause a faster transformation of monoradical ligands of P to the biradical ones on goethite surfaces, while lowering the pH the biradical ligands converted slowly to the monoradical ones. By influencing types of phosphate ions in the solution, pH affected the coordination forms of P on goethite surfaces. The dissociation and association of protons of the sorbed P caused by pH changes were considered as a major reason leading to the transformation of the coordination forms of P on the surfaces. The stability of biradical ligands of P was greater than that of monoradical ones. and the possible reasons were disscussed in paper.