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 C N 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.