In this work, the influences of carbon on structure, magnetic properties and Cr(VI) absorption efficiency of carbon-encapsulated MnFe₂O₄ nanoparticles (MFO/C NPs) are studied. SEM images indicate that the fabricated MnFe₂O₄ nanoparticles (MFO NPs) are enveloped by carbon layers, forming encapsulating structure. By the BET analysis, it is demonstrated that the average specific surface area of MFO/C samples is higher than that MFO sample. From FTIR and XPS spectra, the presence of carbon-coated MnFe₂O₄ nanoparticles is confirmed. It is found that the Cr(VI) absorption efficiency of the MFO/C NPs first increases to reach the maximum value at 5% C concentration, and then decreases with the further increment of C concentration. The maximum absorption efficiency and capacity of 90.1% and 73.26 mg/g are obtained, respectively. Finally, a removal mechanism for the removal of Cr(VI) is proposed. The obtained results demonstrate that the carbon-encapsulated MnFe₂O₄ NPs is a promising candidate as an advanced absorbent for the removal of Cr(VI) from wastewater.

中文翻译：

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碳包裹的MnFe 2 O 4纳米颗粒：碳对结构，磁性和Cr（VI）去除效率的影响

在这项工作中，研究了碳对碳包裹的MnFe ₂ O ₄纳米颗粒（MFO / C NPs）的结构，磁性和Cr（VI）吸收效率的影响。SEM图像表明，所制造的MnFe ₂ O ₄纳米颗粒（MFO NPs）被碳层包裹，形成封装结构。通过BET分析，证明了MFO / C样品的平均比表面积高于MFO / C样品。从FTIR和XPS光谱可以看出，碳包覆的MnFe ₂ O _4的存在纳米颗粒被证实。发现MFO / C NPs的Cr（VI）吸收效率首先增加，在5％的C浓度下达到最大值，然后随着C浓度的进一步增加而降低。获得的最大吸收效率和容量分别为90.1％和73.26 mg / g。最后，提出了一种去除Cr（VI）的去除机理。所得结果表明，碳包封的MnFe ₂ O ₄ NPs是一种有前途的候选物，可以用作从废水中去除Cr（VI）的高级吸收剂。