Efficient adsorption and separation of norfloxacin from water by allophane aerogel microspheres

Norfloxacin contamination in the water environment has garnered international attention due to the dire risks it poses to ecosystems and public health. Aerogel can be easily extracted or separated from aqueous solutions, and it can be used for norfloxacin practical wastewater treatment. In this study, allophane and beta-cyclodextrin were prepared as copolymers, and sodium alginate as a cross-linking agent to prepare allophane aerogel microspheres (A-M) for the efficient separation of norfloxacin in an aqueous environment. The A-M provides a highly three-dimensional porous structure, allowing norfloxacin to effectively penetrate the aerogels and enhancing their adsorption capacity. At pH = 7, the adsorption capacity of allophane microspheres on norfloxacin was 529 mg/g, which was 429 and 209 mg/g higher than that of beta-cyclodextrin and allophane, respectively. Adsorption capacity after 5 regeneration cycles was 78.5% of the initial adsorbents. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that the key adsorption mechanisms of A-M are surface complexation and hydrophobic interaction. Therefore, the prepared A-M materials are excellent adsorbents for the effective separation and removal of norfloxacin from the aquatic environment.