The thermodynamic equilibrium diagrams of Mg2＋- 3-4PO - ＋4NH -H2O system at 298 K were established based on the thermodynamic calculation. From the diagram, the thermodynamic conditions for removing phosphorus from ...The thermodynamic equilibrium diagrams of Mg2＋- 3-4PO - ＋4NH -H2O system at 298 K were established based on the thermodynamic calculation. From the diagram, the thermodynamic conditions for removing phosphorus from the tungstate solution by magnesium salt precipitation were obtained. The results show that when the concentration of total magnesium increases from 0.01 mol/L to 1.0 mol/L, the optimal pH for the phosphorus removal by magnesium phosphate decreases from 9.8 to 8.8. The residual concentration of total phosphorus almost keeps the level of 4.0×10-6 mol/L in the system. MgHPO4, Mg3（PO4）2 and the mixture of Mg3（PO4）2 and Mg（OH）2 are stabilized in these system, respectively. However, increasing the total concentration of magnesium has little effect on phosphorus removal by magnesium ammonium phosphate, while it is helpful for phosphorus removal by increasing the total ammonia concentration. The calculated results demonstrate that the residual concentration of total phosphorus can decrease to 5.0×10-7 mol/L as the total concentration of ammonia reaches 5.0 mol/L and the optimal pH value is 9-10. Finally, verification experiments were conducted with home-made ammonium tungstate solution containing 50 g/L WO3 and 13 g/L P. The results show that when the dosage of MgCl2 is 1.1 times of the theoretical amount, the optimum pH for removing phosphorus is 9.5, which matches with the results of the theoretical calculation exactly.展开更多
In this paper, a new complex inorganic ion exchanger Titanium Phosphate - Ammonium Tungstophosphate (abbreviated as TiP - AWP) was synthesized, whose exchange character and chemical structure were studied, Thiscompoun...In this paper, a new complex inorganic ion exchanger Titanium Phosphate - Ammonium Tungstophosphate (abbreviated as TiP - AWP) was synthesized, whose exchange character and chemical structure were studied, Thiscompound exhibits high exchange capacity and selectivity for Cs+, its exchangecapacity attains 0. 95 mmol/g in the medium of 0. 1 mol/L HNO3, andwhich almost doesn’ t change in the 1 AW imitated waste solution. There areno change in exchange capacity and structure after several times of exchanging,eluting, regenerating, which is of great importance to the separation and uptaking of radio - nuclides. Further more, this exchanger has good thermal andradioactive stability.展开更多
基金Project(2012BAB10B04)supported by the National Key Technologies R&D Program of China
文摘The thermodynamic equilibrium diagrams of Mg2＋- 3-4PO - ＋4NH -H2O system at 298 K were established based on the thermodynamic calculation. From the diagram, the thermodynamic conditions for removing phosphorus from the tungstate solution by magnesium salt precipitation were obtained. The results show that when the concentration of total magnesium increases from 0.01 mol/L to 1.0 mol/L, the optimal pH for the phosphorus removal by magnesium phosphate decreases from 9.8 to 8.8. The residual concentration of total phosphorus almost keeps the level of 4.0×10-6 mol/L in the system. MgHPO4, Mg3（PO4）2 and the mixture of Mg3（PO4）2 and Mg（OH）2 are stabilized in these system, respectively. However, increasing the total concentration of magnesium has little effect on phosphorus removal by magnesium ammonium phosphate, while it is helpful for phosphorus removal by increasing the total ammonia concentration. The calculated results demonstrate that the residual concentration of total phosphorus can decrease to 5.0×10-7 mol/L as the total concentration of ammonia reaches 5.0 mol/L and the optimal pH value is 9-10. Finally, verification experiments were conducted with home-made ammonium tungstate solution containing 50 g/L WO3 and 13 g/L P. The results show that when the dosage of MgCl2 is 1.1 times of the theoretical amount, the optimum pH for removing phosphorus is 9.5, which matches with the results of the theoretical calculation exactly.
文摘In this paper, a new complex inorganic ion exchanger Titanium Phosphate - Ammonium Tungstophosphate (abbreviated as TiP - AWP) was synthesized, whose exchange character and chemical structure were studied, Thiscompound exhibits high exchange capacity and selectivity for Cs+, its exchangecapacity attains 0. 95 mmol/g in the medium of 0. 1 mol/L HNO3, andwhich almost doesn’ t change in the 1 AW imitated waste solution. There areno change in exchange capacity and structure after several times of exchanging,eluting, regenerating, which is of great importance to the separation and uptaking of radio - nuclides. Further more, this exchanger has good thermal andradioactive stability.
