EDTAD-modified cassava stalks loaded with Fe 3 O 4 : highly efficient removal of Pb 2+ and Zn 2+ from aqueous solution
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RESEARCH ARTICLE
EDTAD-modified cassava stalks loaded with Fe3O4: highly efficient removal of Pb2+ and Zn2+ from aqueous solution Caiyan Kang 1,2,3,4
&
Qiuyan Li 1,4 & Hui Yi 4 & Hua Deng 1,2,3,4 & Weiming Mo 5 & Mianwu Meng 1,2,3,4 & Siyu Huang 1,2,3,4
Received: 22 May 2020 / Accepted: 14 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract In this study, a novel magnetic cassava stalk composite (M-EMCS) was prepared through modification with ethylenediamine tetraacetic anhydride (EDTAD) and loading of Fe3O4. 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 Fe3O4 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 Pb2+ and Zn2+ 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 Pb2+ and Zn2+ reached a plateau after 10 min, and the adsorption capacity of Pb2+ (163.93 mg/g) was higher than that of Zn2+ (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 Pb2+ and Zn2+ through ion exchange, chelation, and redox. Keywords Cassava stalk . Magnetic sorbent . Pb2+ and Zn2+ . Adsorption
Introduction Heavy metal pollution in wastewater includes contents of ions such as mercury, cadmium, chromium, lead, zinc, and copper (Zhang et al. 2019a ). The densities of these metals are greater than 5.0 g/cm3. Lead and zinc are common sources of heavy metal pollution. These compounds have received increasing amounts of attention for their toxicity. Excessive concentrations of lead and zinc can potentially harm biological systems
and human health (Qiu et al. 2019). Therefore, effective removal of heavy metals is an important process to eliminate or decrease problems associated with metal ions. There are many ways used to control heavy metal pollution, such as chemical precipitation (Leiva et al. 2018), ion exchange (Murray and Ormeci 2019), membrane separation (López et al. 2019), flocculation (Hou et al. 2019), electrolysis (Ren et al. 2018), and adsorption (Xu et al. 2018). Among them, adsorption is an economical and effective method.
Responsible Editor: Tito Roberto Cadaval Jr * Caiyan Kang [email protected] * Hua Deng [email protected] 1
Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Guangxi Normal University, Guilin 541004, China
2
Department of Education, Key Laboratory of Karst Ecology and Environment Change of Guangxi, Guangxi Norm
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