Separation of Rare-Earth Ions from Mine Wastewater Using B12S Nanoflakes as a Capacitive Deionization Electrode Material.

Abstract

In this study, nanoflakes of B12S were fabricated by plasma-assisted reaction of sulfur dichloride in an ionic liquid at room temperature using europium boride as a hard template. The nanoflakes had an average width and thickness of about 3 1urn and 9.6 nm, respectively, and a large specific surface area of 1197.2 m² g 1. They behaved like typical electric double-layer capacitors with a capacitance of 201.2 F g 1 at 0.2 mA cm ² During capacitive deionization to recover rare-earth ions, the nanoflakes had higher adsorption selectivity for Sm3+ than for other competing ions present in real mine waste water. This is due to the strong interaction of the electron-concentered S-groups (S''') of the nanoflakes with S m3+. This provides an alternative to construct efficient systems to specifically remove Sm3+ from aqueous solution using B12S nanoflakes. This process demonstrates that other boron sulfide compounds can be used to recover valuable ions by capacitive deionization.