Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O Box 80200, Jeddah, 21589, Saudi Arabia.
Schiavello-Grillone Photocatalysis Group, Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze (ed. 6), 90128, Palermo, Italy.
J Environ Manage. 2021 Sep 15;294:112984. doi: 10.1016/j.jenvman.2021.112984. Epub 2021 Jun 4.
Diatomite/kaolinite-based geopolymer (GP) was synthesized and incorporated in zeolitization process (Z/GP) to investigate the role of the zeolite phases in inducing its retention capacity of the dissolved Sr (II) ions in water. The retention of Sr (II) ions using Z/GP in comparison with GP was evaluated based on both batch and fixed-bed column studies. In the batch study, the zeolitized geopolymer (Z/GP) shows enhancement in the Sr (II) retention capacity (193.7 mg/g) as compared to the normal geopolymer (102 mg/g). Moreover, the recyclability studies demonstrate higher stability for Z/GP than GP with a retention percentage higher than 90% for five reusing runs. The kinetic and the equilibrium properties of the occurred Sr (II) retention reactions follow the assumption of the Pseudo-Second order model (R > 0.96) and Langmuir model (R > 0.97), respectively. The Gaussian energies (15.4 kJ/mol (GP) and 11.47 kJ/mol (Z/GP)) related to retention mechanism of chemical type and within the suggested range for the zeolitic ion exchange processes. The Sr (II) retention reactions by GP and Z/GP are of spontaneous and exothermic properties which qualifies the products to be used at low-temperature conditions (20 °C). The column studies also declared higher performance for the Z/GP fixed bed as compared to the normal GP bed considering the total Sr (II) retention percentage (72.9%), treated volume (8 L), saturation time (1620 min), and a maximum capacity of Z/GP particles in the bed (567.6 mg/g).
硅藻土/高岭土基地质聚合物（GP）被合成并纳入沸石化过程（Z/GP）中，以研究沸石相在诱导其对水中溶解的 Sr（II）离子保留能力方面的作用。通过批处理和固定床柱研究评估了 Z/GP 与 GP 相比对 Sr（II）离子的保留能力。在批处理研究中，与正常地质聚合物（102 mg/g）相比，沸石化地质聚合物（Z/GP）显示出增强的 Sr（II）保留能力（193.7 mg/g）。此外，循环使用研究表明，Z/GP 比 GP 更稳定，在五次重复使用中保留率高于 90%。发生的 Sr（II）保留反应的动力学和平衡特性分别遵循拟二级模型（R>0.96）和 Langmuir 模型（R>0.97）的假设。与化学类型的保留机制相关的高斯能（GP 为 15.4 kJ/mol 和 Z/GP 为 11.47 kJ/mol）在沸石离子交换过程的建议范围内。GP 和 Z/GP 对 Sr（II）的保留反应是自发和放热的，这使得产品能够在低温条件（20°C）下使用。与正常 GP 床相比，柱研究还宣布 Z/GP 固定床具有更高的性能，考虑到总 Sr（II）保留百分比（72.9%）、处理体积（8 L）、饱和时间（1620 min）和床中 Z/GP 颗粒的最大容量（567.6 mg/g）。
