摘要
研究了鸟粪石结晶法对经混凝预处理后的垃圾渗滤液中NH4+-N的去除效果,考察了不同影响因素对NH4+-N去除效果的影响,并进行了磷酸铵镁(MgNH4PO4·6H2O,简称MAP)沉淀的表征及成分分析,并提出了反应后溶液中Mg2+、PO43-及MAP的回收利用办法。结果表明,反应的最佳条件为:pH8.5～9.5,Mg2+∶NH4+∶PO34-(摩尔比)=1.1∶1.0∶1.3,反应温度30℃,反应时间为25 min时,此时NH4+-N的去除率达94.70%;最佳沉淀剂投加组合为MgCl2.6 H2O与Na2HPO4·12H2O;pH为9.0时生成的沉淀符合典型MAP沉淀的晶体结构,生成的沉淀大部分为MAP,且没有氰化物、酚等有害物质的检出,而pH为10.5时生成的沉淀由许多疏松的微小沉淀颗粒组成,排列较杂乱,影响了沉淀的纯度。利用鸟粪石结晶法去除混凝预处理后的垃圾渗滤液中NH4+-N技术可行,经济效益合理,具有广阔的应用前景。
The method of struvite crystallization was applied for NH＋-N removal from coagulation pre-treated landfill leachate. Theeffect of pH, Mg2＋ dosage,PO4^3- dosage, temperature, contacting time on treatment efficiency was investigated. The obtained MAP deposition was characterized by SEM and XRD. The optimum reaction condi- tions were found as follow： temperature of 30℃, pH ranged from 8. 5-9. 5, molar ratio of Mg2＋ ,NH4＋ and PO4^3-- was 1.1 ： 1. 0 ： 1. 3 and reacting time of 25 min. Under these conditions, the NH4＋-N removal rate could reach 94.70%. The composition of MgC12 · 6H2O and Na2 HPO4· 12H2O had best effeiciency for NH＋-N removal; the deposition obtained at pH of 9. 0 presented typical MAP crystal structure, the main component of deposition was MgNH4 PO4·6H2 O, while the deposition obtained at pH of 10.5 had irregular structure and lower MAP purity. The given technology was practicable and economical and had broad application prospect.
出处
《环境污染与防治》
CAS
CSCD
北大核心
2010年第3期51-54,59,共5页
Environmental Pollution & Control
基金
天津市科技支撑计划重点项目(No.08ZCKFSH01600)
