Adsorption performance of reduced graphene-oxide/cellulose nano-crystal hybrid aerogels reinforced with waste-paper extracted cellulose-fibers for the removal of toluene pollution

Abstract

In recent years, with the progressive advancement of industries, an enormous amount of polluted effluent has been generated and discharged into the ecosystem. Thus, the aqueous environment has been affected by various kinds of pollution, which threatened the health of living organisms, especially human. Numerous procedures have been developed to eliminate the pollution from the environment, among which the adsorption has been known as an effective method. Up to this point, activated carbon was commercially available as an adsorbent for wastewater treatment. Lately, 3-Dimensional (3D) porous structures, such as Graphene Aerogels (GA) demonstrated supreme potentials of an ideal adsorbent, which introduced the next generation of carbonaceous adsorbents. Herein, we proposed a method based on a mild chemical reduction route to prepare reduced Graphene-Oxide (rGO)/Cellulose Nano-Crystal (CNC) hybrid aerogels. Cellulose Fibers (CFs) extracted from waste-papers were incorporated into the pore-structure as reinforcing agents. Moreover, CNCs were employed to enhance the mechanical stability of rGO sheets, resulting in a 280% increase in the compressive strength of the aerogels. Adsorption performance of the synthesized aerogels, according to ASTM F726-17, exhibited an adsorption capacity of 59 g g−1 for toluene uptake. Besides, the batch adsorption experiments confirmed the pseudo-second-order and Langmuir isotherms as the best-fitted models to explain the adsorption behavior of the adsorbent. The Langmuir isotherm revealed the maximum adsorption capacity of 454 mg g−1 for the removal of toluene from aqueous media. The study showed promising results for graphene-based aerogels to act as the new class of adsorbents.