Interaction between Se(IV) and fulvic acid and its impact on Se(IV) immobility in ferrihydrite-Se(IV) coprecipitates during aging. (15th January 2022)

• Record Type: Journal Article
• Authors: Peng, Jinlong; Fu, Fenglian; Ye, Chujia; Tang, Bing
• Is Part Of: Environmental pollution. Volume 293(2022)
• Publication Date: 2022-01-15
• Subjects: Se(IV) -- Ferrihydrite -- Fulvic acid -- Transformation -- Immobility; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.118552
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Selenium (Se) is regarded as a trace element for humans, but it is toxic in excess. In natural environments, the mobility of Se is dominantly controlled by the Se oxyanions with high solubility such as selenite (Se(IV)). Se(IV) is often associated with the omnipresent ferrihydrite and coexisting organic matter. However, there is little information on the dynamic interactions among Se(IV), fulvic acid, and ferrihydrite. This study investigated the influence of fulvic acid on ferrihydrite-Se(IV) coprecipitates (Fh-Se) transformation for 8 days and the subsequent behavior of Se(IV) at varied pH (5.0, 7.5, and 10.0). Results showed that fulvic acid had different effects on Fh-Se transformation at varied pH values. Fh-Se transformation was promoted by fulvic acid at initial pH 5.0 whereas it was inhibited at initial pH 10.0. Interestingly, at initial pH 7.5, Fh-Se transformation was promoted at a low C/Fe ratio while it was suppressed at a high C/Fe ratio. Besides, fulvic acid induced the generation of more extractable Se(IV) at initial pH 5.0 and more coprecipitated Se(IV) at initial pH 7.5 and blocked the release of Se(IV) at initial pH 10.0. Fulvic acid possibly interacted with Se(IV) via carboxyl complexation and weakened the inhibition of Se(IV) on Fh-Se transformation. Thus, fulvic acid increased the transformation rate of Fh-Se. These findings help to uncover the environmental behavior of Se(IV) and organic matter during ferrihydrite transformation. Graphical abstract: Image 1 Highlights: The fate of Se(IV) in Fh-Se during aging was affected by fulvic acid. pH played an essential role in the immobility of Se(IV) during Fh-Se aging. Fulvic acid promoted Fh-Se transformation due to the generation of ferric selenite. Fulvic acid blocked the release of Se(IV) to environment under alkaline condition.