Study on the Preparation and Adsorption Property of Polyvinyl alcohol/Cellulose Nanocrystal/Graphene Composite Aerogels (PCGAs)

The cellulose nanocrystals/graphene composite aerogel (CGA) and polyvinyl alcohol/cellulose nanocrystals/graphene composite aerogel (PCGA) were prepared by suspension titration, tert-butanol solution replacement and freeze-drying successively. The removal rates of methyl blue (MB) from water by CGA and PCGA were evaluated and the effects of additions, adsorption time, reaction temperature and pH value of CGA and PCGA on MB removal rate were discussed. It was found that the optimal concentrations of both CGA and PCGA were 2 g∙L-1 in the adsorption reaction process and the adsorption equilibrium was reached within 120 min. The higher the initial pH value of MB solution is, the better the removal effect will be. The adsorption kinetics conformed to the pseudo-second-order kinetic model. The langmuir isothermal adsorption equation showed the maximum adsorption capacities of CGA and PCGA were 125 mg∙g-1 and 110.9 mg∙g-1, respectively. Under the conditions of adsorption time of 120 min, reaction temperature of 323 K, and initial MB solution pH value of 11, both CGA and PCGA had higher removal rates of MB, reaching more than 98%.