TEMPO-oxidized cellulose nanofibrils–graphene oxide composite films with improved dye adsorption properties

We report remarkable adsorption capacities of graphene oxide-incorporated 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-modified cellulose nanofibrils (CNF) composite films for Basic Violet 1 and Rhodamine 6g dyes. The morphology of composites shows the formation of open-pore capillary microstructures, typically in only one direction, with a large surface-to-volume ratio and abundance of adsorption voids within the surface down the bulk of the films. The experimental adsorption capacities of Basic Violet 1 and Rhodamine 6g are compared with the theoretical capacities obtained from the pseudo-second-order kinetic model. Moreover, the incorporation of graphene oxide has been found to provide an excellent platform for the stability of adsorbents on CNF and TEMPO-oxidized CNF (TCNF). It is found that TCNF have a remarkable increment in adsorption capacities, typically 100 and 200 times more than CNF, becoming promising industrially viable substrate material for the removal of Basic Violet 1 and Rhodamine 6g.