Arsenic removal from aqueous solutions by mixed magnetite-maghemite nanoparticles
Arsenic removal from aqueous solutions by mixed magnetite-maghemite nanoparticles
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DOI：
10.1007/s12665-010-0865-z
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发表时间：
2011-09-01
影响因子：
2.8
通讯作者：
Pratt, Allen R.
中科院分区：
文献类型：
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作者：
Chowdhury, Saidur Rahman;Yanful, Ernest K.;Pratt, Allen R.
在这项研究中，磁铁矿磁赤铁矿纳米粒子用于处理砷污染的水。X射线光电子能谱（XPS）的研究表明，砷的磁铁矿磁赤铁矿纳米粒子的表面上的存在。磁铁矿-磁赤铁矿混合物（Fe 3 O 4-γ Fe 2 O3）的理论多重峰分析报告了30.8%的磁赤铁矿和69.2%的磁铁矿。结果表明，砷的引入使磁铁矿-磁赤铁矿混合物表面发生氧化还原反应。研究表明，除pH值外，接触时间和砷的初始浓度对砷的去除也有影响。当As（V）和As（III）浓度为2 mg/L，pH值为6.5时，在3 h内达到平衡。结果进一步表明，砷的吸附涉及在磁铁矿-磁赤铁矿表面形成弱的砷-氧化铁复合物。在地下水中，根据Langmuir等温线计算的磁铁矿-磁赤铁矿纳米颗粒在室温下的砷吸附容量为80 μ mol/g，并且用于砷去除的吉布斯自由能（a dagger G（0），kJ/mol）为-35 kJ/mol，表明磁铁矿-磁赤铁矿纳米颗粒上的吸附的自发性质。
In this study, magnetite-maghemite nanoparticles were used to treat arsenic-contaminated water. X-ray photoelectron spectroscopy (XPS) studies showed the presence of arsenic on the surface of magnetite-maghemite nanoparticles. Theoretical multiplet analysis of the magnetite-maghemite mixture (Fe3O4-gamma Fe2O3) reported 30.8% of maghemite and 69.2% of magnetite. The results show that redox reaction occurred on magnetite-maghemite mixture surface when arsenic was introduced. The study showed that, apart from pH, the removal of arsenic from contaminated water also depends on contact time and initial concentration of arsenic. Equilibrium was achieved in 3 h in the case of 2 mg/L of As(V) and As(III) concentrations at pH 6.5. The results further suggest that arsenic adsorption involved the formation of weak arsenic-iron oxide complexes at the magnetite-maghemite surface. In groundwater, arsenic adsorption capacity of magnetite-maghemite nanoparticles at room temperature, calculated from the Langmuir isotherm, was 80 mu mol/g and Gibbs free energy (a dagger G(0), kJ/mol) for arsenic removal was -35 kJ/mol, indicating the spontaneous nature of adsorption on magnetite-maghemite nanoparticles.