MAP沉淀法目标产物最优形成条件及分析方法  

Optimal Formation Conditions and Analytical Methods of the Target Product by MAP Precipitation

作　　者：郝晓地[1] 兰荔[1] 王崇臣[1] van Loosdrecht M C M 

机构地区：[1]北京建筑工程学院可持续环境生物技术研发中心,北京100044 [2]荷兰代尔夫特理工大学Kluyver生物技术实验室,荷兰Delft 2628 BC

出　　处：《环境科学》2009年第4期1120-1125,共6页Environmental Science

基　　金：国家高技术研究发展计划(863)项目(2006AA06Z320);北京市属市管高等学校人才强教计划项目(BJE10016200611);北京市教育委员会科技发展计划面上项目(KM200910016009)

摘　　要：为了确定鸟粪石（MAP：MgNH4PO4.6H2O）形成的最优条件,引入化学剖析法,利用酸溶液将鸟粪石沉淀法中所得沉淀物溶解后进行相应的元素分析;提出一种根据沉淀物中的NH4^＋-N含量间接计算确定鸟粪石含量（即纯度）的分析方法.根据这种计算分析方法,分别得出了不同pH条件下以自来水（主要为地下水）和超纯水作为溶剂所合成的鸟粪石纯度,并对pH和Ca^2＋在鸟粪石形成过程中的影响进行了评估.结果表明,该计算分析方法能够有效实现对MAP沉淀法目标产物的定量分析,弥补了国内外目前普遍依靠XRD技术定性判断所得沉淀物中鸟粪石是否存在的缺陷.以超纯水作为溶剂时,使鸟粪石纯度〉90%的最佳pH范围在7.5-9.0,而以自来水为溶剂时,获得相同鸟粪石纯度最佳pH范围则是7.0-7.5.实际污水中常常含有相当数量的Ca^2＋,实施碱性条件（pH〉8.0）的MAP沉淀势必大幅降低鸟粪石的纯度.因此,对实际污水回收磷而言,MAP沉淀法的最优pH条件应控制在中性范围（〈8.0）以内.In order to establish optimal conditions of the struvite （MAP： MgNH4 PO4 ·6H2 O） formation, acid dissolution was applied and developed to perform element analyses on the precipitates obtained from MAP precipitation, and a novel analyzing and calculating method was developed to quantitatively determine the struvite content （purity） in the harvested precipitates according to the NH4^＋ -N content. With this method, the purities of struvite were respectively determined for both ultra pure water and tap water used as solutes. At the same time, the effect of pH and Ca^2＋ on the formation and crystallization of struvite was evaluated. The newly developed method was effective enough to determine the purities of struvite, which could be a better method than qualitative X-ray diffraction （XRD）. Based on the developed method, it was found that the optimal pH ranges for having a high struvite content （ 〉 90% ） were respectively at 7.5-9.0 with ultra pure water as solute and at 7.0-7.5 with tap water as solute. In real wastewater, Ca^2＋ at pH 〉 8.0 might result in impurities rather than struvite. Therefore, a neutral pH range （ 〈 8.0） is proposed to perform struvite precipitation in wastewater.

关 键 词：鸟粪石 PH CA2+ XRD 酸性溶解法 元素分析 

分 类 号：X703[环境科学与工程—环境工程]