Porous BiOBr/Bi₂MoO₆ Heterostructures for Highly Selective Adsorption of Methylene Blue.

ABSTRACT: Porous BiOBr/Bi₂MoO₆ (Br/Mo) heterostructures were designed and successfully fabricated, in which BiOBr nanoparticles were deposited on the surface of the secondary nanoplate of three-dimensional porous Bi₂MoO₆ architectures through a deposition-precipitation process. The as-prepared Br/Mo heterostructures were used as an adsorbent to remove methylene blue (MB) from aqueous solution. The batch adsorption results indicated that 50.0 wt % Br/Mo heterostructures show an enhanced adsorption capacity compared with pure Bi₂MoO₆ and BiOBr. The effects of initial solution, initial concentration, and contact time were systematically investigated. The optimum adsorbent amount and the pH value were determined to be 0.8 g L^-1 and 2, respectively. Meanwhile, the experiments also revealed that porous Br/Mo heterostructures possess higher preferential adsorptivity for MB than that for methyl orange (MO^-) and rhodamine B (RhB⁺). The dynamic experimental result indicated that the adsorption process conforms to the pseudo-second-order kinetic model. Weber's intraparticle diffusion model indicated that two steps took place during the adsorption process. Thermodynamic analysis results showed that the adsorption is a physisorption process, which conforms to the Langmuir isotherm model. Additionally, the possible adsorption mechanism was also investigated. The present study implied that Br/Mo heterostructures are promising candidates as adsorbents for MB removal. Therefore, fabrication of semiconductor-based heterostructures could be a strategy to design new efficient adsorbents for the removal of environmental pollutants.

SUBMITTER: Wang D 

PROVIDER: S-EPMC6640767 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature