Heavy metals ions in water have attracted close attention due to their toxicity, non-biodegradability and carcinogenicity [1]. Because lead ions are more harmful to the human body and tend to accumulate in the body, their removal from wastewater is necessary [2]. Adsorption method was extensively used to remove/recover toxic metal ions, owing to its low cost, convenient operation, no secondary pollution and diversified nature [3-5]. Most conventional adsorbents are in powder form, which makes it difficult to collect after adsorption. Graphene and its derivative have become widely used for functional materials [6, 7]. Graphene oxide (GO) with plenty of reactive functional groups including hydroxyl, carboxyl and epoxy groups is obtained by strong oxidation and stripping of graphite. Abundant oxygen-containing functional groups can be used as active sites to adsorb heavy metals. Therefore, GO can be widely used in the field of heavy metal adsorption [8, 9]. However, due to the presence of a large number of hydrophilic groups, GO has good hydrophilicity, which makes it difficult to be separated and recycled after adsorption [10, 11]. Therefore, it is necessary to further modify the GO. It is expected to assemble three-dimensional (3D) aerogels by combining GO with chain-like biomass molecules or polymers. Sodium carboxymethyl cellulose (CMC), a hydrosoluble anion linear biopolymer and semi-synthetic derivative of cellulose, is obtained by substituting the 2,3,6-hydroxyl groups of cellulose with a carboxymethyl moiety [12]. Because of its low cost, nontoxic, renewable, biodegradable and modifiable characteristics, CMC is considered a biocompatible material and can be used for drug delivery and tissue engineering. And the CMC aqueous solution still has high viscosity at low concentration, it is widely used as an adhesive in industry. It is also an effective adsorbent for removing metal ions because it contains many active functional groups, including hydroxyl and carboxyl groups that can chelate metal ions and interact with organic compounds. However, it has weak mechanical properties. Therefore, it is difficult to directly assemble GO and CMC to form aerogels with strong mechanical properties. Recent work has demonstrated that during AA reduction of graphene oxide, some oxygen-containing This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
