Hu Chao, Zheng Zuhong, Huang Mengyao, Yang Fan, Wu Xuewei, Zhang Aiqun
Hubei Province Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hubei Engineering University, Xiaogan 432000, China.
College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China.
Polymers (Basel). 2023 Jun 16;15(12):2710. doi: 10.3390/polym15122710.
Optimizing the use of magnetite-chitosan composites for heavy metal adsorption has been of great interest due to their environmental friendliness. To gain insights into their potential with green synthesis, this study analyzed one of these composites through X-ray diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy. Adsorption properties were then explored via static experiments to evaluate the pH dependence, isotherms, kinetics, thermodynamics and regeneration adsorption of Cu(II) and Cd(II). Results disclosed that the optimum pH of adsorption was 5.0, the equilibrium time was about 10 min, and the capacity for Cu(II) and Cd(II) reached 26.28 and 18.67 mg/g, respectively. The adsorption amount of cations increased with temperature from 25 °C to 35 °C and decreased with further increase in temperature from 40 °C to 50 °C, which might be related to the unfolding of chitosan; the adsorption capacity was above 80% of the initial value after two regenerations and about 60% after five regenerations. The composite has a relatively rough outer surface, but its inner surface and porosity are not obvious; it has functional groups of magnetite and chitosan, and chitosan might dominate the adsorption. Consequently, this research proposes the value of maintaining green synthesis research to further optimize the composite system of heavy metal adsorption.
由于其环境友好性，优化磁铁矿-壳聚糖复合材料用于重金属吸附一直备受关注。为深入了解其绿色合成潜力，本研究通过X射线衍射、傅里叶变换红外光谱和扫描电子显微镜对其中一种复合材料进行了分析。然后通过静态实验探索吸附特性，以评估对Cu(II)和Cd(II)的pH依赖性、等温线、动力学、热力学和再生吸附。结果表明，最佳吸附pH为5.0，平衡时间约为10分钟，对Cu(II)和Cd(II)的吸附容量分别达到26.28和18.67 mg/g。阳离子吸附量在25℃至35℃时随温度升高而增加，在40℃至50℃进一步升高时则下降，这可能与壳聚糖的展开有关；两次再生后吸附容量高于初始值的80%，五次再生后约为60%。该复合材料外表面相对粗糙，但其内表面和孔隙率不明显；它具有磁铁矿和壳聚糖的官能团，且壳聚糖可能主导吸附。因此，本研究提出持续开展绿色合成研究以进一步优化重金属吸附复合体系的价值。
