Effect of humic substances on the precipitation of calcium phosphate

作     者：SONG Yong-hui Hermann H. HAHN Erhard HOFFMANN Peter G. WEIDLER 

作者机构：Chinese Research Academy of Environmental Sciences Beijing 100012 China Institute for Aquatic Environmental Engineering University of Karlsruhe Karlsruhe D-76128 Germaay Institute for Technical Chemistry Research Centre of Karlsruhe Eggenstein-Leopoldshafen D-76344 Germany 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2006年第18卷第5期

页      面：852-857页

核心收录：

学科分类：083001[工学-环境科学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 

基　　金：The German Research Foundation (DFG-Graduiertenkolleg 366) Grant Program for the High-Level Returned Scholars fromAbroad, Ministry of Personnel of China (No. 2004-2005) 

主　　题：calcium phosphate phosphorus recovery precipitation humic substances initial CaJP ratio solution pH value 

摘      要：For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate （as P） and 20 mg/L HS （as dissolved organic carbon, DOC） at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium （Ca） and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction （XRD） and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite （HAP） by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.