Highly efficient removal of aqueous chromate and organic dyes by ultralong HCOOBiO nanowires

The ultralong bismuth oxide formate (HCOOBiO; RBi) nanowires (NWs) with a diameter of 20 nm and length up to several hundred micrometers have been prepared in N,N-dimethyl formamide (DMF) solution via a solvothermal route, where DMF served as both solvent and one of the precursors. The high aspect ratio offers nanowires with large porosity and good dispersion in water. Besides, the ultralong RBi NWs possess positively charged surface. All these endow them simple removal performance for anionic species in water including Cr(VI) (predominant forms including HCrO4-, Cr2O72- and CrO42-) and methyl orange (MO) with a maximum adsorption capacity of 171 and 69 mg/g, respectively. As bismuth-based compound, though the surface area of RBi NWs is not so high as the other adsorbents like SiO2 and activated carbon, the positively charged surface together with unique structures could compensate for this deficiency and enhance anions removal. Moreover, RBi NWs also exhibit enhanced photocatalytic performance for Rhodamine B (RhB) degradation, which could be completely decomposed after 9 min of UV-light illumination. The as-prepared RBi NWs could be potential candidates as both adsorbent and photocatalyst in wastewater treatment. (C) 2014 Elsevier B.V. All rights reserved.