Derbe Tessema, Sani Taju, Zereffa Enyew Amare
Department of Industrial Chemistry, Addis Ababa Science and Technology University P.O. Box 16417 Addis Ababa Ethiopia
Nanotechnology Center of Excellence, Addis Ababa Science and Technology University P.O. Box 1647 Addis Ababa Ethiopia.
RSC Adv. 2025 May 9;15(19):15200-15217. doi: 10.1039/d5ra01995h. eCollection 2025 May 6.
Consumption of excessive F from groundwater harms human health and can cause bone and dental fluorosis. To reduce the excessive F concentration from groundwater, a novel zeolite-A/MOF-5 (Z-A/MOF-5) composite was synthesized through the solvothermal method. The phase structure, functional group, weight loss, morphology, and elemental composition were characterized by using PXRD, FT-IR, TGA, SEM, and EDX, respectively. The surface charge of the Z-A/MOF-5 composite showed a positive surface up to a pH value of 8.1, which is accessible for the defluoridation of groundwater. The defluoridation efficiency of the Z-A/MOF-5 adsorbent was activated by optimizing defluoridation conditions. The maximum defluoridation efficiency (88.20%) and capacity (11.025 mg g) were recorded at a pH of 3, 1.2 g L of adsorbent dose, 6 h of contact time, and 10 mg L initial concentration of F ( ) at ambient temperature. However, the defluoridation efficiency of the Z-A/MOF-5 composite still maintained its efficiency (85.50%) up to a pH of 7, which is applicable for the defluoridation of groundwater. The defluoridation data were well fitted with the Freundlich isotherm model and pseudo-second-order kinetics, confirming that defluoridation mainly proceeds chemisorption on the heterogeneous surface of the Z-A/MOF-5 composite. The defluoridation performance of the Z-A/MOF-5 composite was tested on real water samples having 12.25 and 8.5 mg L F taken from Ziway and Kenteri towns, Ethiopia, that reduced the concentration of F to 1.48 and 0.82 mg L, respectively. Interestingly, the recyclability study showed defluoridation efficiencies of 88.20%, 87.90%, 86.80%, 85.60%, 82.00%, and 70.10% for the 1, 2, 3, 4, 5, and 6 runs, respectively. Consequently, the synthesized composite is a promising adsorbent for practical application.
饮用来自地下水的过量氟会危害人体健康，并可能导致骨氟病和牙氟病。为了降低地下水中过量的氟浓度，通过溶剂热法合成了一种新型的沸石-A/金属有机框架-5（Z-A/MOF-5）复合材料。分别使用粉末X射线衍射（PXRD）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）、扫描电子显微镜（SEM）和能谱分析（EDX）对其相结构、官能团、失重、形态和元素组成进行了表征。Z-A/MOF-5复合材料的表面电荷在pH值为8.1之前呈正表面，这有利于地下水的除氟。通过优化除氟条件激活了Z-A/MOF-5吸附剂的除氟效率。在环境温度下，当pH为3、吸附剂剂量为1.2 g/L、接触时间为6 h、初始氟浓度为10 mg/L时，记录到最大除氟效率（88.20%）和容量（11.025 mg/g）。然而，Z-A/MOF-5复合材料的除氟效率在pH值为7时仍保持其效率（85.50%），这适用于地下水的除氟。除氟数据与弗伦德利希等温线模型和伪二级动力学拟合良好，证实除氟主要通过在Z-A/MOF-5复合材料的异质表面上的化学吸附进行。在取自埃塞俄比亚Ziway镇和Kenteri镇的氟含量分别为12.25 mg/L和8.5 mg/L的实际水样上测试了Z-A/MOF-5复合材料的除氟性能，结果分别将氟浓度降低到了1.48 mg/L和0.82 mg/L。有趣的是，可回收性研究表明，在第1次至第6次运行中，除氟效率分别为88.20%、87.90%、86.80%、85.60%、82.00%和70.10%。因此，合成的复合材料是一种有实际应用前景的吸附剂。
