Bioinspired synthesis of mesoporous ZrO2 nanomaterials with elevated defluoridation performance in agarose gels

Abstract

Mesoporous ZrO₂ nanomaterials were synthesized in an agarose gel medium by a bioinspired approach, and their adsorption capacity for the fluoride anion was also evaluated. The obtained ZrO₂ samples after calcination at 600 °C for 2 h are primarily composed of tetragonal nanocrystals about 11.8 nm in size. Moreover, the samples possess bimodal mesopores about 3.5 nm and 5.9 nm in diameter, which are generated by removing the agarose gel fibers embedded in the ZrO₂ particles during their growth process. The pore volume and specific surface area of mesoporous ZrO₂ nanomaterials are 0.091 cm³ g⁻¹ and 40.14 m² g⁻¹, respectively, which increase with the increase of gel concentration, while decrease with the increase of initial ZrOCl₂ concentration. The ZrO₂ samples synthesized in agarose gel show a higher fluoride adsorption capacity than those synthesized in the aqueous solution by the same method. This study may provide a broader insight into the bioinspired synthesis of metal oxides in hydrogel medium under mild conditions.