采用热重分析仪研究了空气气氛中废弃医用外科口罩的热氧化降解特性,并运用3种无模型方法以及1种模型拟合方法进行了动力学和热力学分析。结果表明:废弃医用外科口罩在空气气氛中的热氧化降解是一种吸热的非自发反应,且整个热氧化降解...采用热重分析仪研究了空气气氛中废弃医用外科口罩的热氧化降解特性,并运用3种无模型方法以及1种模型拟合方法进行了动力学和热力学分析。结果表明:废弃医用外科口罩在空气气氛中的热氧化降解是一种吸热的非自发反应,且整个热氧化降解过程可被认为是单步反应。热氧化降解过程的活化能和指前因子的平均值分别为63.83 k J·mol^(-1)和1.27×10^(5) min^(-1),最概然反应模型为g(a)-[-ln(1-a)]^(2/3),所获得的动力学参数可用于较好地预测废弃医用外科口罩在空气中的热氧化降解行为。研究结果可以为预防废弃医用外科口罩可能引发的火灾事故提供参考。展开更多
Using a synthetic method designed and installed with computer monitor on line, the solubility values of melamine in water were determined and were in good agreement with traditional analytic method data. The solubilit...Using a synthetic method designed and installed with computer monitor on line, the solubility values of melamine in water were determined and were in good agreement with traditional analytic method data. The solubilities of melamine in alcohol and dimethyl sulfoxide were also determined with this method. The experimental data were correlated with Apelblat equation.展开更多
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
文摘采用热重分析仪研究了空气气氛中废弃医用外科口罩的热氧化降解特性,并运用3种无模型方法以及1种模型拟合方法进行了动力学和热力学分析。结果表明:废弃医用外科口罩在空气气氛中的热氧化降解是一种吸热的非自发反应,且整个热氧化降解过程可被认为是单步反应。热氧化降解过程的活化能和指前因子的平均值分别为63.83 k J·mol^(-1)和1.27×10^(5) min^(-1),最概然反应模型为g(a)-[-ln(1-a)]^(2/3),所获得的动力学参数可用于较好地预测废弃医用外科口罩在空气中的热氧化降解行为。研究结果可以为预防废弃医用外科口罩可能引发的火灾事故提供参考。
文摘Using a synthetic method designed and installed with computer monitor on line, the solubility values of melamine in water were determined and were in good agreement with traditional analytic method data. The solubilities of melamine in alcohol and dimethyl sulfoxide were also determined with this method. The experimental data were correlated with Apelblat equation.
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.
