Optimization of Crystallization of Magnesium Ammonium Phosphate: Initial Phosphate Concentration, PH and Reactants Molar Ratio

Abstract:

By- products are widespread in the crystallization of magnesium ammonia phosphate (MAP) as the differences in reactive conditions which effects the forms and habits of crystals. The study focused on the supernatant from septic tank in order to achieve in-situ treatment. Based on the effluent, the optimization research of initial phosphate concentration and pH was investigated by using single factor analysis. The crystal products with different reaction condition were also characteristiced through the XRD analysis. The experimental results showed that the optimum reactants molar ratio of n(NH4+):n(Mg2+):n(PO43-) were 90:25:1, 4:1.6:1 and 3:1.4:1 when pH value was 9.5 with initial phosphate concentration 8mg/L, 50mg/L and 100mg/L, respectively. It was also observed that the phosphate removal rate increased with increasing the initial phosphate concentration or pH value. As the aging time increased, the removal rate was in parabolic curve with 30 minute at the highest point. The XRD analysis revealed that the best MAP crystal could be produced with initial phosphate concentration 50mg/L and pH 9.0.

• Periodical: Applied Mechanics and Materials (Volumes 295-298)
• Pages: 1289-1292
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.295-298.1289
• Online since: February 2013
• Authors: Kai Huang, Li Ping Qiu, Jin Feng Meng, Dong Wang
• Keywords: In Situ Treatment, Initial Phosphate Concentration, Magnesium Ammonium Phosphate Crystallization, pH, Septic Tank Wastewater

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