School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
Environ Sci Pollut Res Int. 2019 Oct;26(29):30498-30507. doi: 10.1007/s11356-019-06261-0. Epub 2019 Aug 23.
MnFeO was a magnetic material that can be used to adsorb contaminants in the wastewater. Fe(II) could act as a reductant to transfer Cr(VI) into Cr(III). In this paper, mesoporous MnFeO prepared by the coprecipitation method was incorporated with Fe(II) to remove Cr(VI). The samples before and after reaction were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. A total of 98~100% of Cr(VI) in solution was removed by MnFeO/Fe(II) hybrid system within a wide pH range (pH 3.0-9.0), which is due to the synergetic effects of adsorption from MnFeO and reduction from Fe(II). Cr(VI) was reduced to Cr(III) by ≡Mn(II) on MnFeO and Fe(II). Cr(III) and Fe(III) produced during reaction formed Cr(III)-Fe(III) hydroxides/oxyhydroxides and deposited on MnFeO. The inhibiting action of phosphate on the removal of Cr(VI) was greater than that of sulfate. Cr(VI) removal rate retained 94.5% at the fourth recycle test, which showed excellent re-usability of MnFeO.
MnFeO 是一种可用于吸附废水中污染物的磁性材料。Fe(II)可作为还原剂将 Cr(VI)转化为 Cr(III)。本文采用共沉淀法制备了介孔 MnFeO，并将其与 Fe(II)结合以去除 Cr(VI)。通过 X 射线衍射、扫描电子显微镜、透射电子显微镜、傅里叶变换红外光谱和 X 射线光电子能谱对反应前后的样品进行了表征。在宽 pH 范围（pH 3.0-9.0）内，MnFeO/Fe(II) 混合体系可去除溶液中 98%~100%的 Cr(VI)，这归因于 MnFeO 的吸附和 Fe(II)的还原的协同作用。Cr(VI)被 MnFeO 上的≡Mn(II)和 Fe(II)还原为 Cr(III)。反应过程中生成的 Cr(III)和 Fe(III)形成 Cr(III)-Fe(III)氢氧化物/水羟化物并沉积在 MnFeO 上。磷酸盐对 Cr(VI)去除的抑制作用大于硫酸盐。在第四次循环测试中，Cr(VI)去除率仍保持在 94.5%，表明 MnFeO 具有优异的可重复使用性。
