Chitosan modified silicon dioxide composites for the capture of graphene oxide

Graphene oxide (GO) is considered as a toxic carbon material, and the adverse impact of GO has been realized. Herein, the spherical chitosan modified silicon dioxide (CS/SiO2) was prepared to eliminate GO. Considering the effects of hydroxyl and amidogen groups, the introduction of chitosan onto silicon dioxide can not only change the morphology and size of the composite but also increase the removal capacity for GO. The experimental results demonstrated that the removal of GO onto the CS/SiO2 composites relied on pH and ionic strength. The maximum removal capacity of CS/SiO2 for GO was 111.8 mg/g, and the elimination of GO was endothermic. Based on the characterization analysis, the electrostatic attraction played the main role in GO removal process. Furthermore, the hydroxyl groups and amidogen groups on the surface of CS/SiO2 formed a hydrogen bond with GO, which was conducive to GO capture. This work promoted the trapping of GO and provided an example for other nanomaterials removal from the aquatic environment.