Adsorption of antibiotics from aqueous solution by different aerogels

In this paper, silica aerogels and carbon aerogels were prepared by ambient pressure drying and freeze drying, respectively. The microstructure and adsorption capability of the two kinds of aerogels for antibiotics in water were investigated. The results showed that silica aerogels and carbon aerogels exhibited completely different adsorption capability for antibiotics although they possessed similar specific surface area (665–765 m2/g) and pore volume (1.6–3.0 cm3/g). The silica aerogel, no matter how they are hydrophobic or hydrophilic, both showed much lower adsorption rate for antibiotics than the carbon aerogel. By contrast, the carbon aerogel and magnetic carbon aerogel both showed excellent adsorption performance for antibiotics, with the adsorption rate for terramycin within 180 min attaining to 99.9%. The adsorption mechanism of terramycin on the two kinds of aerogels was studied using kinetic adsorption models. It has been clarified that the adsorption process of the two aerogels is mainly based on chemical adsorption with the assistance of physical adsorption. Moreover, the carbon aerogel exhibited higher adsorption stability for antibiotics without desorption phenomenon, and the magnetic carbon aerogels have excellent recycling utilization performance.