Silsesquioxane-crosslinked chitosan aerogels with highly selective adsorption for Au(III).

A novel water-soluble silsesquioxane precursor (DEA-GSQ) was prepared by the nucleophilic substitution reaction of diethanolamine (DEA) with glycidyloxypropyl substituted silsesquioxane (GSQ). DEA-GSQ can be used to crosslink chitosan to prepare hybrid aerogels (DGCA). The hybrid aerogels were fully characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, compression performance test and Mercury intrusion porosimetry. The hybrid aerogel shows selective adsorption for Au(III) with the saturated adsorption capacity of 918.16 mg/g at pH = 6. Pseudo-second-order model and Langmuir model could describe the adsorption process well. It was found that Au(III) was mostly reduced to Au(0) by CN bond during the adsorption process. Furthermore, an adsorption device was designed to remove Au(III) based on this hybrid aerogel, laying the foundation for the adsorption of Au(III) in practical applications.