Efficient performances of hierarchical Bi24O31Br10 microspheres for Congo red dye adsorption

Abstract

Developing new, high-efficiency and environmentally-friendly adsorbents are of great importance for more efficient removal of contaminants from wastewater. Therefore, it is necessary to adjust the synthesis parameters to control the surface area and morphology of the adsorbent, thereby improving the adsorption performance. Herein, hierarchical nanoflakes-assembled Bi24O31Br10 microspheres with high removal capacity of organic dyes were rationally designed and prepared by an ethylene glycol (EG) mediated solvothermal method. Different morphological Bi24O31Br10 and BiOBr were controllably synthesized by adjusting the amount of EG and pH value. A possible mechanism of formation was proposed from the results of morphological evolution. Congo red (CR) was adopted as typical contaminants to prove the absorption capacity of such unique Bi24O31Br10 hierarchical structures. The adsorption isotherm conforms to the Langmuir model, which provides the maximum calculated adsorption capacity of the nanoflakes-assembled hierarchical Bi24O31Br10 microspheres 465.1 mg/g. The adsorption mechanisms of CR onto Bi24O31Br10 mainly attributed to the electrostatic attraction and hydrogen bonding. The as-prepared Bi24O31Br10 hierarchical structure can be used as a candidate material for the removal of contaminants in wastewater.