El Shenawy Rehab S, Hassan Asaad F, El Fadaly Ezzat A
Survey of Natural Resources Department, Environmental Studies and Research Institute, University of Sadat City, Sadat City, Egypt.
Department of Chemistry, Faculty of Science, Damanhour University, Damanhour, Egypt.
Int J Biol Macromol. 2025 Sep;322(Pt 4):146995. doi: 10.1016/j.ijbiomac.2025.146995. Epub 2025 Aug 20.
The increasing contamination of water resources by toxic dyes, particularly methylene blue (MB), presents a critical environmental challenge. This study introduces a novel copper-terephthalate metal-organic framework (Cu-BDC) integrated with ferric xanthan gum (X) to form a Cu-BDC/X composite for effective dye adsorption. The composite was synthesized and characterized using physicochemical analysis to confirm structural integration and enhanced surface features. The material exhibited improved thermal stability, mesoporosity (pore radius, r¯ = 2.42 nm), specific surface area (13.9 m/g), and an anionic surface (pH at point of zero charge, pH = 3.075), with a particle size of 84 nm. Batch adsorption studies showed a maximum MB adsorption capacity of 164.33 mg/g under optimal conditions (2.0 g/L dosage, pH 7, 20 °C, 6 h). Kinetic modeling followed a pseudo-second order model, and equilibrium data fit both Langmuir and Freundlich isotherms, indicating mixed monolayer-multilayer adsorption behavior. Thermodynamic analysis showed spontaneous MB adsorption (ΔG°, -1.255 to -7.673 kJ/mol); Cu-BDC was exothermic (ΔH°, -22.91), while X and Cu-BDC/X were endothermic (8.12 and 25.53 kJ/mol). Notably, the Cu-BDC/X composite retained 94 % of its adsorption capacity after eight regeneration cycles, confirming excellent reusability and structural stability. This work highlights the potential of Cu-BDC/X as a sustainable and efficient adsorbent for wastewater treatment applications.
有毒染料，尤其是亚甲基蓝（MB）对水资源的污染日益严重，这是一个严峻的环境挑战。本研究引入了一种新型的铜-对苯二甲酸金属有机框架（Cu-BDC），并与黄原胶铁（X）结合，形成一种用于有效吸附染料的Cu-BDC/X复合材料。通过物理化学分析对该复合材料进行了合成和表征，以确认其结构整合和增强的表面特性。该材料具有改善的热稳定性、介孔率（孔半径，r¯ = 2.42 nm）、比表面积（13.9 m/g）和阴离子表面（零电荷点pH值，pH = 3.075），粒径为84 nm。批量吸附研究表明，在最佳条件下（剂量2.0 g/L、pH值7、20°C、6小时），MB的最大吸附容量为164.33 mg/g。动力学建模遵循准二级模型，平衡数据符合Langmuir和Freundlich等温线，表明存在混合单层-多层吸附行为。热力学分析表明MB的吸附是自发的（ΔG°，-1.255至-7.673 kJ/mol）；Cu-BDC是放热的（ΔH°，-22.91），而X和Cu-BDC/X是吸热的（8.12和25.53 kJ/mol）。值得注意的是，Cu-BDC/X复合材料在八个再生循环后仍保留其94%的吸附容量，证实了其优异的可重复使用性和结构稳定性。这项工作突出了Cu-BDC/X作为一种可持续且高效的吸附剂在废水处理应用中的潜力。
