The characterization and application of prussian blue at graphene coated carbon fibers in a separated adsorption and electrically switched ion exchange desorption processes of cesium

•Prussian blue/graphene/carbon fibers composite (PB/GN/CFs) was prepared by electrochemical method with rising specific surface area and ameliorative chemical stability.•Characterization of PB/GN/CFs in a separated adsorption and electrically switched ion exchange desorption processes of cesium ions was investigated.•PB/GN/CFs showed good regeneration ability and long-term cycle stability.•PB/GN/CFs could be used to the recovery of cesium ions from the residual salt lake brine.•Cesium ions could be desorbed in pH 2 0.1 M NH4Cl with a significantly increased concentration.

Iron hexacyanoferrate/graphene/carbon fibers composite (PB/GN/CFs) was prepared by electrochemical method. Characterization of PB/GN/CFs in a separated adsorption and electrically switched ion exchange desorption processes (Ads-ESIX) of cesium ions (Cs+) was confirmed by FE-SEM, XRD, IR, XPS and electrochemistry techniques. PB/GN/CFs displayed two quasi reversible transformations from FeIII4(FeII(CN)6)3 to FeIII4(FeIII(CN)6Cl)3, or to (NH4)4FeII4[FeII(CN)6]3 at a potential range of −0.1-1.2 V in pH 2, 0.1 M NH4Cl. The recovery of Cs+ was investigated by PB/GN/CFs using Ads-ESIX method. Cs+ could be selectively adsorbed by PB/GN/CFs from aqueous solution in pH 7.0, and desorbed in pH 2, 0.1 M NH4Cl. The desorption rate of Cs+ depended on the introduction of potential at PB/GN/CFs in pH 2, 0.1 M NH4Cl. Both H3O+ and NH4+ could play dual role of electrolyte and competitor for the desorption of Cs+. PB/GN/CFs could be used to the recovery of Cs+ from the residual salt lake brine in which potasium had been removed from Qarham playa of Qaidam Basin in China.

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