Redox mechanisms of conversion of Cr(VI) to Cr(III) by graphene oxide-polymer composite
Redox mechanisms of conversion of Cr(VI) to Cr(III) by graphene oxide-polymer composite
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DOI：
10.1038/s41598-020-65534-8
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发表时间：
2020-06-08
影响因子：
4.6
通讯作者：
Rodrigues, D. F.
中科院分区：
文献类型：
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作者：
Bandara, P. C.;Pena-Bahamonde, J.;Rodrigues, D. F.
由于 Cr (VI) 是一种剧毒化合物，会对人类健康造成严重影响，因此水相除铬的替代方法近年来引起了极大的研究兴趣。为了更好地去除 Cr (VI)，必须了解导致从溶液中成功去除 Cr 物质的化学反应。最近的研究表明，基于氧化石墨烯 (GO) 的聚合物珠不仅可以通过静电引力吸附 Cr (VI)，还可以将其还原为 Cr (III)，这是一种毒性较小的铬形式。迄今为止，这种转化以及参与这种转化的官能团尚未得到阐明。在本研究中，我们采用 X 射线光电子能谱和傅里叶变换红外光谱来研究石墨烯基聚合物珠中 Cr (VI) 到 Cr (III) 的转化途径。结果表明，醇基转化为羧基，同时将 Cr(VI) 还原为 Cr(III)。聚合物珠中含有 GO 极大地增加了 Cr (VI) 吸收和转化为 Cr (III) 的潜力，表明含有醇基团的聚合物和纳米材料可以去除和转化水中的铬。聚合物珠中存在的其他官能团在吸附中发挥重要作用，但不参与 Cr (VI) 到 Cr (III) 的转化。
Alternative methods of aqueous chromium removal have been of great research interest in recent years as Cr (VI) is a highly toxic compound causing severe human health effects. To achieve better removal of Cr (VI), it is essential to understand the chemical reactions that lead to the successful removal of Cr species from the solution. Recent studies have demonstrated that graphene oxide (GO) based polymer beads cannot only adsorb Cr (VI) via electrostatic attractions but also reduce it to Cr (III), which is a much less toxic form of chromium. This conversion and the functional groups involved in this conversion, until now, were not elucidated. In the present study, we employed X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy to investigate the conversion pathway of Cr (VI) to Cr (III) in graphene-based polymer beads. The results showed that alcoholic groups are converted to carboxylic groups while reducing Cr (VI) to Cr (III). The inclusion of GO in the polymer beads dramatically increased the potential of Cr (VI) uptake and conversion to Cr (III), indicating polymers and nanomaterials containing alcohol groups can remove and convert chromium in water. Other functional groups present in the polymer bead play an important role in adsorption but are not involved in the conversion of Cr (VI) to Cr (III).