College of Chemistry, Green Catalysis Center, Zhengzhou University, No 100 of Kexue Road, Zhengzhou 450001, PR China.
School of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, No 90 of Wangcheng Road, Luoyang 471000, PR China.
J Colloid Interface Sci. 2022 Jan 15;606(Pt 2):1249-1260. doi: 10.1016/j.jcis.2021.08.097. Epub 2021 Aug 18.
In this study, an iron(III)-loaded magnetic chitosan/graphene oxide composite (Fe-MCG) was synthesized and applied for the adsorptive removal of sulfosalicylic acid (SSA) in aqueous solution. The results obtained from the application of various characterization techniques such as scanning electron microscopy (SEM), vibrating-sample magnetometry (VSM), and X-ray photoelectron spectroscopy (XPS) prove the successful formation of the composite with enhanced microstructure and superparamagnetic properties. The adsorption capacity of Fe-MCG towards SSA via batch mode reaches up to 135 mg/g at 293 K. The adsorption of SSA onto Fe-MCG is driven by monolayer adsorption with the chemical and physical adsorption processes both playing active roles. The Langmuir isotherm and pseudo-second-order kinetic models were observed to best describe the equilibrium adsorption and kinetic processes, respectively. The values obtained for the associated thermodynamic parameters confirm that the adsorptive process is spontaneous, exothermic and entropy-increasing. The efficacy and reusability of the spent Fe-MCG was studied using 0.01 mol/L NaOH solution. The kinetic process for the desorption of SSA from Fe-MCG is well described by the pseudo-second-order kinetic model. Based on the experimental results and XPS analysis, the underlying mechanisms for the uptake of SSA onto Fe-MCG involve electrostatic forces, complexation, π-π stacking, and hydrogen bonding. Overall, the excellent features of Fe-MCG enhance its potential as an adsorbent for the sequestration of SSA in environmental media.
在这项研究中，合成了一种负载铁（III）的磁性壳聚糖/氧化石墨烯复合材料（Fe-MCG），并将其应用于水溶液中对磺胺水杨酸（SSA）的吸附去除。通过扫描电子显微镜（SEM）、振动样品磁强计（VSM）和 X 射线光电子能谱（XPS）等多种表征技术的应用，结果证明了复合材料的成功形成，其具有增强的微观结构和超顺磁性。在 293 K 时，Fe-MCG 通过批量模式对 SSA 的吸附容量达到 135 mg/g。SSA 吸附到 Fe-MCG 上是由单层吸附驱动的，其中化学吸附和物理吸附过程都发挥了积极作用。观察到 Langmuir 等温线和拟二级动力学模型分别最能描述平衡吸附和动力学过程。相关热力学参数的值证实了吸附过程是自发的、放热的和熵增加的。使用 0.01 mol/L NaOH 溶液研究了用过的 Fe-MCG 的功效和可重复使用性。SSA 从 Fe-MCG 上解吸的动力学过程很好地符合拟二级动力学模型。根据实验结果和 XPS 分析，SSA 被 Fe-MCG 吸收的潜在机制涉及静电力、络合、π-π 堆积和氢键。总体而言，Fe-MCG 的优异特性增强了其作为环境介质中 SSA 螯合剂的潜力。
