CAJ | 학술논문

研究了Mg-Al水滑石在水溶液中的溶解性能及其机理，考察了温度和pH对其溶解性能的影响,探讨了溶解过程中动力学和热力学规律。动力学研究表明，Mg-Al水滑石在水溶液中的溶解符合外扩散及表面化学反应控制模型，且不同pH区间其控制步骤不同。pH=1.0～3.8，水滑石完全溶解，其溶解速率随pH的提高而减小，受解吸控制。而pH=4.2～9.4，水滑石部分溶解，溶解速率与pH 值无关，受表面交换反应控制。另一方面，对水滑石溶解反应的Gibbs自由能变进行定量估算，其值为29.516 kJ·mol-1。经实验验证，理论估算可很好地与实验结果吻合。
연구료Mg-Al수활석재수용액중적용해성능급기궤리，고찰료온도화pH대기용해성능적영향,탐토료용해과정중동역학화열역학규률。동역학연구표명，Mg-Al수활석재수용액중적용해부합외확산급표면화학반응공제모형，차불동pH구간기공제보취불동。pH=1.0～3.8，수활석완전용해，기용해속솔수pH적제고이감소，수해흡공제。이pH=4.2～9.4，수활석부분용해，용해속솔여pH 치무관，수표면교환반응공제。령일방면，대수활석용해반응적Gibbs자유능변진행정량고산，기치위29.516 kJ·mol-1。경실험험증，이론고산가흔호지여실험결과문합。
The dissolution of Mg-Al hydrotalcites in aqueous solution and its mechanism were investigated, with the dissolution kinetics and thermodynamics at different temperatures and pH. The kinetic model with the outer diffusion and chemical reaction control can be used to describe the dissolution process appropriately, with different controlling steps in various pH ranges. In the pH range from 1.0 to 3.8, the hydrotalcites dissolve completely and the dissolution rate decreases as pH increases, with the dissolution controlled by desorption. In the pH range from 4.2 to 9.4, the hydrotalcites partly dissolve, independent of pH, with the dissolution controlled by surface exchange reaction. On the other hand, the Gibbs free energy change of the dissolution reaction from the Mg-Al hydrotalcite is estimated as 29.516 kJ·mol-1 at 298 K. The result is consistent with the experimental evidence.