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以牛粪厌氧消化液为研究对象,选用Mg Cl2·6H2O和Na2HPO4·12H2O为沉淀剂,进行磷酸铵镁(MAP)结晶试验,研究了氮磷比、镁磷比、p H值、反应温度和搅拌速度对磷酸铵镁结晶过程的影响;并利用扫描电镜(SEM)、X射线衍射(XRD)对产物进行表征。结果表明,当氮磷比为1.2、镁磷比为1.0、p H值在8.5~10.5之间时,氮的回收率均在75.0%以上,磷的回收率可达99.0%,溶液中剩余PO3-4-P浓度均在8.0 mg/L以下。此外,MAP结晶法可同步去除消化液中的部分悬浮物;而提高反应温度和搅拌速度不能明显增加氮、磷的回收率。
Taking cow dung anaerobic digestive juice as the research object, MgCl 2 · 6H 2 O and Na 2 HPO 4 · 12H 2 O were selected as the precipitating agent to carry out the crystallization experiment of MAP. The effects of nitrogen and phosphorus ratio, magnesium and phosphorus ratio, p H value, reaction temperature And stirring speed on the crystallization process of magnesium ammonium phosphate. The products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that when the ratio of nitrogen and phosphorus was 1.2, the ratio of magnesium to phosphorus was 1.0, and the value of p H was between 8.5 and 10.5, the recoveries of nitrogen were above 75.0% and the recoveries of phosphorus were up to 99.0%. The remaining PO3 -4-P concentrations were below 8.0 mg / L. In addition, the MAP crystallization method can simultaneously remove part of the suspended solids in the digestive juice; while increasing the reaction temperature and stirring speed can not significantly increase the recovery of nitrogen and phosphorus.