CAJ | 학술논문

对NH_4~+-Mg~(2+)_-PO_4~(3-)-H~+-H_2O体系中固相MgNH_4PO_4,Mg_3(PO_4)_2,MgHPO_4及Mg(OH)_2与液相间的热力学平衡关系进行计算,绘制溶液总镁与总磷摩尔比为1-1时该体系的lgcMg-pH图、lgcN-lgcMg图和lgcN-pH图,确定体系中各种固相稳定存在的pH值范围.结果表明,溶液中的氨氮浓度和pH值是影响固相稳定存在的重要因素,MgNH_4PO_4的稳定区随氨氮浓度的降低而变小并最终消失,当pH=8.5且MgNH_4PO_4与Mg3(PO_4)_2共存时,溶液中的氨氮平衡浓度最低.
대NH_4~+-Mg~(2+)_-PO_4~(3-)-H~+-H_2O체계중고상MgNH_4PO_4,Mg_3(PO_4)_2,MgHPO_4급Mg(OH)_2여액상간적열역학평형관계진행계산,회제용액총미여총린마이비위1-1시해체계적lgcMg-pH도、lgcN-lgcMg도화lgcN-pH도,학정체계중각충고상은정존재적pH치범위.결과표명,용액중적안담농도화pH치시영향고상은정존재적중요인소,MgNH_4PO_4적은정구수안담농도적강저이변소병최종소실,당pH=8.5차MgNH_4PO_4여Mg3(PO_4)_2공존시,용액중적안담평형농도최저.
The thermodynamics of equilibrium was calculated between solid phases MgNH_4PO_4, Mg_3(PO_4)_2, MgHPO_4, Mg(OH)_2 and liquid phase in NH_4~+-Mg~(2+)-PO_4~(3-)-H~+-H_2O system. The lgcMg-PH, lgCN-igcMg and lgcN-PH diagrams when the molar ratio N(Mg)/n(P) was equal to 1:1 in liquid phases were drawn, and the pH range when solid phases existed stably in the system was determined. The results show that the ammonia-nitrogen concentration and pH are very important factors which influence the stable zone of solid phases. The stable zone of MgNH_4PO_4 reduces and finally disappears with the decrease of ammonia-nitrogen concentration. The lowest ammonia-nitrogen concentration in equilibrium is found at pH=8.5 when MgNH_4PO_4 and Mg_3(PO_4)_2 coexist with liquid phase.