Mdlalose Lindani, Balogun Mohammed, Klavins Maris, Deeks Christopher, Treacy Jon, Chimuka Luke, Chetty Avashnee
Polymers and Composites, Materials Science and Manufacturing, Council for Scientific and Industrial Research, P.O Box 395, Pretoria, 0001, South Africa E-mail:
Department of Environmental Science, University of Latvia, Raina Blvd 19, Riga LV-1586, Latvia.
Water Sci Technol. 2018 Dec;78(12):2481-2488. doi: 10.2166/wst.2018.531.
Water pollution due to industrial processes has necessitated and spurred robust research into the development of adsorbent materials for remediation. Polyphenylenediamines (PPD) have attracted significant attention because of their dual cationic and redox properties. They are able to reduce Cr(VI) to Cr(III) in solution. Interrogation of the chemical processes involved in the Cr(VI) adsorption on para-PPD was primarily by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. It was confirmed that the underlying oxidation of the amino groups to imines during the reduction of Cr(VI) to Cr(III) was irreversible. This process occurred at both acidic and alkaline conditions. Reduction was accompanied by Cr(III) chelation on the adsorbent surface. Further, regeneration with dilute aqueous NaOH and HCl extended the polymer's adsorptive capacity beyond exhaustion of its redox potentials.
工业生产过程造成的水污染促使人们大力开展用于修复的吸附材料开发研究。聚苯二胺（PPD）因其兼具阳离子和氧化还原特性而备受关注。它们能够将溶液中的Cr(VI)还原为Cr(III)。对Cr(VI)在对聚苯二胺上吸附所涉及的化学过程的研究主要采用X射线光电子能谱（XPS）和傅里叶变换红外（FT-IR）光谱法。已证实，在Cr(VI)还原为Cr(III)的过程中，氨基向亚胺的潜在氧化是不可逆的。此过程在酸性和碱性条件下均会发生。还原过程伴随着吸附剂表面的Cr(III)螯合。此外，用稀氢氧化钠水溶液和盐酸再生可使聚合物的吸附容量在其氧化还原电位耗尽后仍得以扩展。
