Intrinsic facet-dependent electrochemical activities of BiOBr nanosheets for Br- exchange in electrochemically switched ion exchange process

An Electroactive BiOBr/PVDF/CB Film Electrode for Electrochemical Extraction of Bromine Ions from Brines

“…To date, the EIXMs that have already been developed are mainly divided into two categories: inorganic and organic. The inorganic EIXMs that have been extensively developed and studied are mainly transition metal inorganic compounds, such as transition metal hexacyanoferrates (MHCFs), 20 bismuth oxyhalides (BiOX), 21 layered double hydroxides (LDHs), 22 and manganese dioxide (MnO 2 ), 23 while organic EIXMs are mainly conductive polymers, such as polypyrrole (PPy), 24 polyaniline (PANI), 25 LDH 22 and BiOBr, 26 35 However, the electrodeposition process has many influencing factors, and the deposition amount was limited, which made the method remain in the laboratory stage and difficult to scale up to industrial applications. Based on the shortcomings of the above work, it was necessary to develop a simple and low-cost synthetic method and a pilot system that was suitable for industrial applications.…”

“…The inorganic EIXMs that have been extensively developed and studied are mainly transition metal inorganic compounds, such as transition metal hexacyanoferrates (MHCFs), bismuth oxyhalides (BiOX), layered double hydroxides (LDHs), and manganese dioxide (MnO 2 ), while organic EIXMs are mainly conductive polymers, such as polypyrrole (PPy), polyaniline (PANI), and polythiophene (PTh). The EIXMs that have been developed for Br – extraction included NiCo LDH and BiOBr, among which BiOBr has attracted increasing attention as a cheap and environmentally friendly active material with excellent ion recognition properties. BiOBr consisted of a layer of [Bi 2 O 2 ] 2+ and double layers of Br – staggered arrangement, forming [−Br–Bi-O–O–Bi–Br−] layer, through the weak nonbonding (van der Waals) interaction of Br – , forming the layered stacking structure.…”

Electricity-Triggered Simultaneous Cesium and Bromide Ion Exchange of BiOBr in an Electrochemically Switched Ion Exchange Process

“…during the polymerization process of the conductive polymer, the polymer exhibits anion exchange performance; if the size of the doped anion is larger (such as PSS n− ), the conductive polymer displays a cation exchange property. 39,40 Currently, for inorganic electroactive functional materials, metal hexacyanoferrates (MHCF), 16,41,42 layered double hydroxides (LDH), 21,27 and bismuth oxy-halogen (BiOX, X = Cl, Br, I) 23,43 are mainly researched and applied. Among them, BiOX as a semiconductor layered material is formed by the [Bi 2 O 2 ] layer and double halogen layer, where Bi and O atoms in the layers are connected by strong covalent bonds, while the X atoms are located in the layers through van der Waals forces.…”

“…45 Wang et al prepared BiOBr by in situ electrochemical deposition and it displays excellent ESIX activity toward Br − in aqueous solution. 23 However, the research of Lin et al revealed that BiOBr possesses ESIX activity toward cations Li + , Na + , and Cs + , especially for Cs + . 46 These studies suggest that like PANI and PPy, BiOBr also exhibits ESIX activity toward both cations and anions.…”

“…Here, the regeneration of the EIXMs is achieved by the regulation of the electrode potential rather than the addition of chemical reagents, and this environmentally friendly property makes ESIX technology attract more and more attention. To date, ESIX technology has been used for the separation of heavy metal ions (Ag + , Ca 2+ , Mg 2+ , Ni 2+ , Pb 2+ , − Cu 2+ , Zn 2+ , Y 3+ ), radioactive ion (Cs + − ), high value-added ions (Li + − ), halogen ions (F – , Cl – , Br – , I – , ), oxyanions (NO 3 – , ClO 4 – , ), and so on.…”