摩尔配比对MAP沉淀法回收模拟废水中磷的影响  

Molar Ratio Effect on Phosphorus Recovery by MAP from Simulative Wastewater

作　　者：薛罡[1] 王燕群[1] 刘亚男[1] 

机构地区：[1]东华大学环境科学与工程学院,上海201620

出　　处：《环境科学与技术》2010年第1期170-173,共4页Environmental Science & Technology

基　　金：教育部新世纪人才支持计划;教育部科学技术研究重点项目(107046);上海市自然科学基金(04ZR14010)

摘　　要：以磷浓度50mg/L的实验室模拟废水为研究对象,考察了以鸟粪石(MAP)形式回收磷的最佳摩尔配比,并借助X-衍射(XRD)对不同摩尔配比条件下得到的沉淀物进行分析。试验结果表明,在pH=9.5时,以鸟粪石形式回收磷的最佳Mg:N:P=4:1.6:1。对沉淀物的XRD分析发现,在pH=9.5,当固定Mg:P=1.6时,N:P=1时沉淀物中基本不含MAP,当N:P=2时,生成的沉淀物中混有少量的副产物Mg(3PO)42,当N:P>2时则生成较纯的MAP;当固定N:P=4时,Mg:P=2是生成较纯的MAP的临界值,超过此比例则生成副产物Mg(3PO)42;当反应按照理论配比投加氨氮和镁盐时,所得产物基本不是MAP,而是副产物Mg(3PO)42。故鸟粪石沉淀结晶反应中应尽量提高氨氮配比,并避免投加过量的镁盐,以保证回收产物的纯度。Phosphorus recovery by struvite from simulative wastewater with phosphorus concentration of 50mg/L was studied under the condition of molar ratio. X-ray diffraction （XRD） was used to analyze the identity of the precipitate produced under different molar ratio. Results showed that at pH 9.5,the optimum Mg ： N ： P is 4 ： 1.6 ： 1. XRD results showed that the precipitate weren＇t struvite basically at pH 9.5 and Mg：P 1.6, when N ： P 1; whenN ： P at 2, the precipitate contained a little outgrowth of Mga（PO4）2; when N ： P〉2, that were almost only struvite. When pH 9.5 and N ： P at 4, the critical molar ratio of Mg ： P for purer precipitate was 2; when Mg ： P molar ratio was higher than 2, the outgrowth of Mg3（PO4）2 would be produced. With stoichiometric concentration of three ions, the precipitate wasn＇t struvite but outgrowth Mg3（PO4）2. Therefore, increasing the ammonium concentration and avoiding excess magnesium would increase the purity of the precipitate on struvite crystallization.

关 键 词：鸟粪石 摩尔配比 磷回收率 X-衍射 

分 类 号：X703[环境科学与工程—环境工程]