Electrochemical Selective Recovery of Heavy Metal Vanadium Oxyanion from Continuously Flowing Aqueous Streams. Issue 15 (30th June 2020)

• Record Type: Journal Article
• Authors: Hemmatifar, Ali; Ozbek, Nil; Halliday, Cameron; Hatton, T. Alan
• Is Part Of: ChemSusChem. Volume 13:Issue 15(2020)
• Page Start: 3865
• Page End: 3874
• Publication Date: 2020-06-30
• Subjects: aqueous streams -- electrochemistry -- metallocenes -- resource recovery -- vanadium; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.202001094
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: An electrochemical flow cell with redox‐active electrodes was used for selective removal and recovery of vanadium(V) oxyanions from aqueous streams. The cell relies on intrinsic affinity of the redox‐active polymer poly(vinyl)ferrocene (PVFc) and demonstrates selectivity of >10 towards vanadium compared to a background electrolyte in 40‐fold abundance. We demonstrate highly selective vanadium removal in the presence of various competing anions (i.e., fluoride, bromide, nitrate, and sulfate). Surface elemental analysis reveals significant correlation between PVFc moieties and vanadium‐rich regions after adsorption, corroborating the central role of PVFc modulation on vanadium separation. We further propose a vanadium speciation mechanism in which high and low pH environments during adsorption and desorption steps favor formation of, respectively, H2 VO3 − / HVO4 2− and H2 VO3 − / H3 VO4 / VO2 + . Results have implications for the development and optimization of flow devices, as per our observations, excessively low pH environments during desorption can lead to subsequent re‐adsorption of cationic vanadium(V). Abstract : Selective recovery : An asymmetric, redox‐active electrochemical flow platform for selective recovery of vanadium(V) oxyanions from aqueous streams. The selectivity of >10 relative to the background anion present in a 40‐fold abundance, and in the presence of various competing anions, attests to the promise for such electrochemically mediated separations to address environmental contamination problems, as well as for resource recovery from process and recycle streams.