Selective removal of Cl− and F− from complex solution via electrochemistry deionization with bismuth/reduced graphene oxide composite electrode

Electro-adsorption is attracting increasing attention as an emerging technology for removing ionic species from water but suffer from low selectivity. In this work, a bismuth/reduced graphene oxide nanocomposite electrode was fabricated by a facile and green method. Based on this material, an electrode with improved selectivity by electrochemistry deionization system was successfully fabricated. The bismuth nanoparticles were uniformly covered with reduced graphene oxide plates and the ratio of Bi on the whole materials is 79.56%. Bismuth/reduced graphene oxide showed ions selectivity in the order of Cl− > F− ≫ SO42−. The average Cl− removal capacity can reach as high as 62.59 mg g−1. Moreover, bismuth/reduced graphene oxide electrodes have good regeneration performance. Typically, in the 10 adsorption-desorption multicycles, the salt absorption/desorption capacity of the hybrid capacitive deionization system is stable and reversible. This research opened a hopeful window to design and synthesize effective materials to selectively remove the ionic species to purify the water. [Display omitted] •A novel Bi/rGO composite electrode was fabricated by a green method for EDI system.•The Bi/rGO electrode presented high selectivity for F− and Cl− and regeneration.•The mechanism of F− and Cl− selectively adsorption was illuminated.•The electrochemical adsorption process of Cl−, F−, SO42− and NO3− is suggested.