Effects of oxalate and citrate on the behavior and redistribution of Cr(VI) during ferrihydrite-Cr(VI) co-precipitates transformation. (March 2021)

• Record Type: Journal Article
• Authors: Yu, Peijing; Fu, Fenglian; Sun, Guangzhao; Tang, Bing
• Is Part Of: Chemosphere. Volume 266(2021)
• Publication Date: 2021-03
• Subjects: Cr(VI) -- Ferrihydrite-Cr(VI) co-precipitates -- Oxalate -- Citrate -- Transformation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128977
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Understanding the influence of organic matters on the fate of Cr(VI) during ferrihydrite-Cr(VI) (Fh-Cr) co-precipitates transformation helps to study the retention of Cr(VI) by iron oxides in the environment. In this paper, Fh-Cr was prepared by co-precipitation and the redistribution of Cr(VI) in the oxalate or citrate system during the transformation of Fh-Cr was studied. X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize Fh-Cr for aging 7 days at 70 °C. Results showed that both oxalate and citrate could hinder the release of Cr(VI) from Fh-Cr and abate the harm of Cr(VI). Oxalate improved the transformation from Fh-Cr to hematite and promoted Cr(VI) to be enfolded into the secondary minerals to further immobilize Cr at initial pH of 5.0 and 7.0, while citrate evidently reduced the release of Cr(VI) through stabilizing Fh-Cr at initial pH of 9.0. Besides, reduction of Cr(VI) by oxalate and citrate was through forming the surface complexes that promoted electron transfer from oxalate or citrate to Cr(VI), which can effectively abate the harm of Cr(VI). The findings of this study can promote understanding of the influences of organic matters on Cr(VI) immobilization during transformation of iron oxides in nature. Graphical abstract: Image 1 Highlights: Oxalate and citrate affecting Cr behavior during Fh-Cr transformation were studied. Oxalate promoted the incorporation of Cr into iron minerals during transformation. Citrate inhibited Fh-Cr transformation and Cr incorporation into iron minerals. Citrate prevented the release of Cr to the environment under alkaline condition. Reduction of Cr(VI) to Cr(III) by oxalate and citrate occurred during conversion.