Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
Department of Chemistry, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia.
Int J Biol Macromol. 2024 Nov;281(Pt 1):136194. doi: 10.1016/j.ijbiomac.2024.136194. Epub 2024 Oct 2.
This research presents a novel nanocomposite of ferrous metal-organic framework (Fe(II)-MOF) that has been encapsulated with chitosan matrix, leading to the development of a new adsorbent referred to as NH-Fe(II)-MOF@CSC composite sponge. This composite sponge has shown effectiveness in removing radioactive thorium (IV) contamination from water sources. The adsorbent underwent characterization using techniques including FTIR, PXRD, BET analysis, and SEM. The adsorbent has a high surface area of 1360.8 m/g. The most effective conditions for adsorbing Th(IV) were found to be a pH of 5, using 0.02 g of adsorbent dose per 25 mL, and maintaining a contact time of 100 min. The composite sponge demonstrated an impressive maximum adsorption capacity of 618.8 mg/g for Th(IV). The adsorption process was fitted to Langmuir isothermally and kinetically fitted to pseudo-second-order. Nonetheless, the relatively low adsorption energy of 6.22 kJ/mol suggests that the main adsorption mechanism is physisorption, which is marked by weaker van der Waals forces. This discovery could have implications for the material's potential for easy regeneration. In the analysis of the influence of temperature on the adsorption of Th(IV), it was discovered that the adsorption process is endothermic because the positive ΔH value was 24.48 kJ.mol. Furthermore, a positive ΔS value of 87.46 J.mol K suggests the existence of disorder at the solid-solution interface. Conversely, a temperature rise resulted in a higher negatively charged ΔG, indicating that the adsorption process is spontaneous. The research also examined the mechanism of interaction, such as π-π interaction, hydrogen bonding, pore filling, and electrostatic interaction. It was noted that the adsorbent can be efficiently used for a maximum of six cycles, demonstrating its economic viability. The adsorption outcomes were optimized using the Box Behnken design (BBD).
本研究提出了一种新型的亚铁金属有机骨架（Fe(II)-MOF）纳米复合材料，该材料被壳聚糖基质包裹，形成了一种新型的吸附剂，称为 NH-Fe(II)-MOF@CSC 复合海绵。该复合海绵已被证明能有效去除水源中的放射性钍（IV）污染。该吸附剂经过傅里叶变换红外光谱（FTIR）、粉末 X 射线衍射（PXRD）、BET 分析和扫描电子显微镜（SEM）等技术进行了表征。该吸附剂具有 1360.8 m/g 的高表面积。发现吸附 Th(IV) 的最佳条件为 pH 值为 5，使用 0.02 g 吸附剂剂量吸附 25 mL 水样，接触时间为 100 min。复合海绵对 Th(IV) 的最大吸附容量达到 618.8 mg/g。吸附过程符合 Langmuir 等温线，动力学拟合符合伪二阶模型。然而，相对较低的吸附能 6.22 kJ/mol 表明主要的吸附机制是物理吸附，其特征是较弱的范德华力。这一发现可能对该材料易于再生的潜力产生影响。在分析温度对 Th(IV) 吸附的影响时，发现吸附过程是吸热的，因为正的 ΔH 值为 24.48 kJ/mol。此外，正的 ΔS 值 87.46 J/mol K 表明固液界面存在无序。相反，温度升高导致负的 ΔG 值升高，表明吸附过程是自发的。研究还考察了相互作用的机制，如 π-π 相互作用、氢键、孔填充和静电相互作用。结果表明，吸附剂在 6 个循环内可以有效地使用，具有经济可行性。吸附结果通过 Box Behnken 设计（BBD）进行了优化。
