生态环境学报Issue(9)：1594-1601,8.
磷酸盐改性方解石去除水中磷酸盐研究
Removal of phosphate from aqueous solution by phosphate-modified calcite
摘要
Abstract
Previous literatures have shown that calcite can be used to effectively remove phosphate from aqueous solution. In this study, the calcite-phosphate reaction product, i.e., phosphate-modified calcite was reused to remove phosphate from aqueous solution. The phosphate removal kinetics of natural calcite and phosphate-modified calcite were compared. The effect of various experimental conditions such as solution pH, initial phosphate concentration, temperature, Ca2+ and HCO3- on phosphate removal by phosphate-modified calcite was investigated. The phosphate removal efficiency of phosphate-modified calcite was much higher than that of natural calcite. When the reaction time was 2 h, the phosphate removal efficiency of phosphate-modified calcite was 72%under the experimental conditions, which was much higher than that of natural calcite (35%). The phosphate removal efficiency of phosphate-modified calcite was relatively high at pH 5-7, slightly decreased with increasing pH from 7 to 10, and significantly decreased with increasing pH from 10 to 12. The amount of phosphate removed by phosphate-modified calcite increased with increasing initial phosphate concentration. The phosphate removal efficiency of phosphate-modified calcite decreased with increasing initial phosphate concentration at a relatively high initial phosphate-phosphorus concentration (60-160 mg·L-1). The phosphate removal efficiency of phosphate-modified calcite increased with increasing temperature. The phosphate removal kinetics of phosphate-modified calcite followed a pseudo-second-order kinetic model. The removal of phosphate by phosphate-modified calcite occurred predominantly via the precipitation of calcium phosphate according to two consecutive phases:first, the dissolution of calcite produced an increase in the Ca2+concentration;then the Ca2+ions reacted with the phosphate ions to form the precipitate of calcium phosphate. The precipitation of calcium phosphate took place at the surface of phosphate-modified calcite, which acted as substrate for the heterogeneous nucleation of calcium phosphate. The presence of Ca2+ions in aqueous solution represented a further source of Ca2+ions that were available for the precipitation of calcium phosphate, thus resulting in an increase in phosphate removal efficiency of phosphate-modified calcite. Coexisting HCO3- in aqueous solution was unfavorable for the removal of phosphate by phosphate-modified calcite. As a general conclusion, the calcite-phosphate reaction product can be reused to remove phosphate from aqueous solution, and it is a more effective media for the removal of phosphate than the original calcite.关键词
磷酸盐改性方解石/去除/动力学/沉淀Key words
phosphate-modified calcite/removal/kinetics/precipitation分类
资源环境引用本文复制引用
林建伟,李佳,詹艳慧..磷酸盐改性方解石去除水中磷酸盐研究[J].生态环境学报,2013,(9):1594-1601,8.基金项目
国家自然科学基金项目（50908142）；上海市科学技术委员会科研项目（10230502900）；上海高校青年教师培养资助计划项目（ZZhy12012）；上海市教委重点学科建设项目 （）
