Highly efficient adsorption of anionic dyes on a porous graphene oxide nanosheets/chitosan composite aerogel

Graphene oxide nanosheets (GONs) treatment of anionic dyeing wastewater has been characterized by low removal efficiency due to its electronegativity. However, further modification and enhancement of graphene oxide make it difficult to balance cost and efficiency. Herein, we report an economical, practical, and environmentally friendly composite aerogel of GONs and chitosan (CS) in anionic dye adsorption. The abundant oxygen-containing functional groups on the surface of GONs may form hydrogen bonds with dye molecules. Meanwhile, the amino-positive active sites on the chain segments of CS molecules may anchor anionic dyes. The adsorption capacities of composite aerogel for methyl orange (MO) and bromophenol blue (BPB) anionic dyes by electrostatic attraction, hydrogen bonds, and π-π conjugate interactions are 3.7 and 1.8 times than that of pure CS aerogel from the adsorption results, respectively. Moreover, the maximum adsorption capacities of composite aerogel for MO and BPB are 179.21 and 236.42 mg g −1 at room temperature and in a neutral environment. Therefore, this simple and cost-effective graphene aerogel anionic dye adsorbent may be used for the protection of the water environment.