Preparation Of Cellulose-Graphene Aerogel Adsorbents And Their Performance Evaluation

As a new type of porous carbon material,graphene-based aerogel has special properties that make it exhibit good properties for adsorption.In this paper,cellulose was introduced into aerogels.The cellulose-graphene composite aerogels were prepared by hydrothermal reduction reaction and freeze-drying.Different types of composite aerogels with different properties were prepared by changing the mass ratio between cellulose and GO and the types of cellulose.The cellulose-graphene composite aerogels were characterized by different characterization.Adsorption experiments were carried out with the cationic dye methylene blue(MB)and three different heavy metal ions as adsorption targets.The adsorption mechanism was studied through the experimental data analysis.The graphene oxide was prepared by the modified Hummers method.GO and the anionic ether type carboxymethyl cellulose(CMC)were mixed at a certain mass ratio,and the well-formed carboxymethyl cellulose-graphene aerogel(CMC-GA)can be obtained.The characterization results indicated that CMC was combined with GO well in the CMC-GA.The CMC-GA has a good 3D pore structure.Also,it has a certain compression resilience performance.Microcrystalline cellulose(MCC)was used as the main body.It was dissolved by environmentally friendly green alkali urea system.And GO solution was added into MCC solution at a certain mass ratio.Microcrystalline cellulose-graphene composite aerogel(MCC-GA)was prepared after hydrothermal reduction reaction and freeze-drying.The characterization results showed that MCC and GO were combined together well.MCC-GA has obvious lamellar structure and it has great mechanical strength.The results of CMC-GA adsorption onto MB showed that the larger the initial concentration of MB solution was,the larger the equilibrium adsorption amount of CMC-GA was.It was found that higher adsorption temperature is better for the adsorption.It was consistent with the Langmuir model by the adsorption isotherm fitting.Also,it is known that the adsorption was endothermic and the degree of disorder increased.and a spontaneous physical adsorption process.As well as,the kinetic model fitting is more consistent with the pseudo-second-order model.The results of MCC-GA adsorption onto heavy metal ions showed that the adsorption on hexavalent chromium ion showed the best effect at p H=2,while it showed the best effects under neutral conditions for copper ion and lead ion.The adsorption isotherms of the three kinds of heavy metal ions are all consistent with the Freundlich model.It was found that the adsorption process was an endothermic,disordered and spontaneous physical process.The kinetics of them were consistent with the pseudo-second-order model.