Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Guangxi Normal University, Guilin, 541004, China.
Department of Education, Key Laboratory of Karst Ecology and Environment Change of Guangxi, Guangxi Normal University, Guilin, 541004, China.
Environ Sci Pollut Res Int. 2021 Feb;28(6):6733-6745. doi: 10.1007/s11356-020-10858-1. Epub 2020 Oct 2.
In this study, a novel magnetic cassava stalk composite (M-EMCS) was prepared through modification with ethylenediamine tetraacetic anhydride (EDTAD) and loading of FeO. The surface morphology, molecular structure, and magnetic characteristics of the composite were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), vibrating-sample magnetometer (VSM), and X-ray diffraction (XRD). It was shown that EDTAD and FeO were successfully modified and loaded in cassava straw (CS), respectively. The capacity of M-EMCS to absorb heavy metals under different influencing factors was tested by atomic absorption spectroscopy. The adsorption processes of both Pb and Zn were suitably described by second-order kinetic models and Langmuir models, indicating monolayer chemisorption. M-EMCS had high adsorption rates and adsorption capacities for these two metal ions. The adsorption of Pb and Zn reached a plateau after 10 min, and the adsorption capacity of Pb (163.93 mg/g) was higher than that of Zn (84.74 mg/g). Thermodynamic analysis showed that the adsorption of two metals by M-EMCS was spontaneous, endothermic, and irreversible. XPS analysis showed that M-EMCS mainly removes Pb and Zn through ion exchange, chelation, and redox. Graphical abstract.
在这项研究中，通过乙二胺四乙酸酐（EDTAD）改性和 FeO 负载，制备了一种新型磁性木薯秸秆复合材料（M-EMCS）。采用扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）、振动样品磁强计（VSM）和 X 射线衍射（XRD）对复合材料的表面形貌、分子结构和磁性特征进行了表征。结果表明，EDTAD 和 FeO 分别成功地修饰和负载到木薯秸秆（CS）上。通过原子吸收光谱法测试了 M-EMCS 在不同影响因素下对重金属的吸附能力。Pb 和 Zn 的吸附过程均适合用二级动力学模型和 Langmuir 模型描述，表明为单层化学吸附。M-EMCS 对这两种金属离子具有较高的吸附速率和吸附容量。Pb 和 Zn 的吸附在 10 分钟后达到平衡，Pb（163.93 mg/g）的吸附容量高于 Zn（84.74 mg/g）。热力学分析表明，M-EMCS 对两种金属的吸附是自发、吸热和不可逆的。XPS 分析表明，M-EMCS 主要通过离子交换、螯合和氧化还原去除 Pb 和 Zn。
