부산대학교 도서관

High-purity magnesium ammonium phosphate (MAP) was precipitated by controlling pH value of the reaction system of 9.0–9.5. The thermal decomposition behavior of MAP and the adsorption properties of its pyrolysis products toward ammonia–nitrogen were also studied by XRD, SEM, TGA-DTA and FT-IR methods. The results indicated that high-purity MAP was obtained at pH value of 9.0–9.5. Upon heating to 100–120 °C for 120 min, MAP was thermally decomposed, losing water and ammonia concomitantly with a reduction in grain size and crystallinity. The capacity of pyrolysis products for ammonia nitrogen adsorption reached 72.5 mg/g, with a removal rate of up to 95% from an 800 mg/L solution. The characteristic diffraction peaks corresponding to MAP mainly appeared in their XRD patterns after adsorption of ammonia nitrogen. The pyrolysis products of MAP at 100–120 °C could be recycling-used as the chemical treatment regents of ammonia nitrogen in the practical application.