Kamel Mohamed S, Abdelrahman Ehab A, Anwar Zinab M, El Rayes Samir M, Abou-Krisha Mortaga M, Hegazey Raed M, Alhussain Hanan
Chemistry Department, Faculty of Science, Suez Canal University, Ismailia, 41522, Egypt.
Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), 11623, Riyadh, Saudi Arabia.
Sci Rep. 2025 May 12;15(1):16456. doi: 10.1038/s41598-025-99232-0.
Cadmium ions constitute a major threat to human health and the environment owing to their toxicity, bioaccumulation, and persistence in water bodies, causing renal dysfunction, cancer, and cardiovascular diseases. Hence, this study reports the facile fabrication of a novel sodium iron oxide silicate@amorphous sodium iron silicate product (S1) and its chitosan composite (S1@chitosan) for the high-performance separation of Cd(II) ions from aquatic environments. The Brunauer-Emmett-Teller surface area, total pore volume, and mean pore diameter of S1 were 94.97 m/g, 0.5853 cm/g, and 25.65 nm, respectively, while those for S1@chitosan were 30.94 m/g, 0.09518 cm/g, and 12.31 nm, respectively. The reduction in pore diameter, pore volume, and surface area confirms the successful functionalization of S1 with chitosan, as the chitosan coating partially blocks and fills the pores, reducing the available surface area and porosity. Also, scanning electron microscope (SEM) images revealed an uneven surface morphology for S1 and a more textured and rougher surface for S1@chitosan, supporting the incorporation of chitosan. Besides, energy-dispersive X-ray spectroscopy (EDX) and CHN analyses affirmed the existence of chitosan in the composite through the detection of carbon and nitrogen elements, characteristic of chitosan. The optimum conditions for the removal of Cd(II) ions were determined to be a contact time of 70 min for S1 and 50 min for S1@chitosan, a pH of 7.50, and a temperature of 298 K. The maximum sorption capacities were 284.09 mg/g for S1 and 389.11 mg/g for S1@chitosa. The removal mechanism for S1 primarily involves ion exchange, while S1@chitosan utilizes both ion exchange and complexation through the amino and hydroxyl groups of chitosan. Regeneration using HCl confirmed the effective reusability of both adsorbents over five successive cycles. The adsorption process was found to be chemical, exothermic, and best described by the pseudo-second-order kinetic model and Langmuir isotherm.
镉离子因其毒性、生物累积性以及在水体中的持久性，对人类健康和环境构成重大威胁，会导致肾功能障碍、癌症和心血管疾病。因此，本研究报告了一种新型硅酸钠铁@无定形硅酸钠铁产物（S1）及其壳聚糖复合材料（S1@壳聚糖）的简便制备方法，用于从水生环境中高效分离Cd(II)离子。S1的 Brunauer-Emmett-Teller 表面积、总孔体积和平均孔径分别为 94.97 m²/g、0.5853 cm³/g 和 25.65 nm，而 S1@壳聚糖的分别为 30.94 m²/g、0.09518 cm³/g 和 12.31 nm。孔径、孔体积和表面积的减小证实了壳聚糖对 S1 的成功功能化，因为壳聚糖涂层部分堵塞并填充了孔隙，减少了可用表面积和孔隙率。此外，扫描电子显微镜（SEM）图像显示 S1 的表面形态不均匀，而 S1@壳聚糖的表面更有纹理且更粗糙，这支持了壳聚糖的掺入。此外，能量色散X射线光谱（EDX）和CHN分析通过检测壳聚糖特有的碳和氮元素，证实了复合材料中壳聚糖的存在。去除Cd(II)离子的最佳条件确定为S1的接触时间为70分钟，S1@壳聚糖的接触时间为50分钟，pH为7.50，温度为298K。最大吸附容量S1为284.09 mg/g，S1@壳聚糖为389.11 mg/g。S1的去除机制主要涉及离子交换，而S1@壳聚糖则通过壳聚糖的氨基和羟基利用离子交换和络合作用。用HCl再生证实了两种吸附剂在连续五个循环中都具有有效的可重复使用性。吸附过程被发现是化学的、放热的，并且用伪二级动力学模型和Langmuir等温线能最好地描述。
