A novel method for synthesis of Co–Al layered double hydroxides and their conversions to mesoporous CoAl2O4 nanostructures for applications in adsorption removal of fluoride ions

•Mesoporous Co–Al LDHs with rodlike and nanosheet-like morphologies were synthesized via micro-emulsion method.•The calcined Co–Al sample with 10% content of cobalt exhibits the highest specific surface area.•The calcined samples exhibit higher fluoride removal efficiency than the uncalcined ones.•Performance of the adsorption decreases with an increase in the cobalt ratio generally.•The adsorption kinetics and isotherms were also discussed.

Facile micro-emulsion methods have been developed to synthesize mesoporous Co–Al hydroxide carbonates with rodlike and hexagonal sheetlike morphologies. A series of samples with different molar ratio of cobalt/aluminum were prepared to investigate the impact of cobalt content. Employing transmission electron microscopy, X-ray diffraction analysis and Fourier transformed infrared spectra, the morphology, structure and composition of the products were investigated. Characterized by gas-sorption measurements, the specific surface area of the calcined S-10 sample with the rodlike morphology was as high as 379 m2/g, which provided this material porosity properties and outstanding fluoride removal efficiency as high as 95.6%. The sorptive removal capacity of fluoride from aqueous solutions by the precursors and their corresponding annealed products was investigated in a batch mode. Also, the adsorption kinetics and isotherms were discussed.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide