Cellulose and chitosan biopolymer composites reinforced with graphene and their adsorption properties for basic blue 41

Abstract

Chitosan/cellulose (CH/CE/GA) and chitosan/cellulose/graphene (CH/CE/G/GA) composites crosslinked via glutaraldehyde were used for the efficient adsorption of basic blue 41 (BB). FT-IR and C-13 solid-state NMR spectroscopy confirmed the crosslinking reaction of chitosan via glutaraldehyde, whereas XRD and TGA analysis proved the interactions between chitosan, cellulose, and graphene in the composites. FE-SEM and AFM studies provided evidence for the changes in the morphological and topological properties of the composites due to crosslinking reactions. Introducing graphene into the composites improved the specific surface areas, which led to enhanced thermal stability, swelling ratio, and dye adsorption capacity. The BB adsorption ability of the prepared crosslinked composites was investigated based on contact time, initial BB concentration, pH, and temperature. The Langmuir adsorption isotherm model was better fitted to the adsorption data of the composites relative to the Freundlich isotherm model. The pseudo-second-order kinetic model better correlates the adsorption of BB onto the prepared composites. The maximum adsorption capacity of CH/CE/GA was calculated as 107.87 mg/g using the Langmuir isotherm model, achieving a relatively higher maximal adsorption value of 129.3 mg/g with the CH/CE/G/GA composite after introducing graphene. Furthermore, the prepared composites demonstrated efficient BB adsorption properties and could be offered as environmentally friendly, stable materials for dye removal in wastewater treatments.