Fruit waste-derived cellulose and graphene-based aerogels: Plausible adsorption pathways for fast and efficient removal of organic dyes

Abstract

A wide range of organic pollutants in industrial effluents, agricultural runoff, and domestic discharges are exacerbating water scarcity, leading to water-borne ailments, and adversely affecting the marine ecosystem and biodiversity. The efficient, sustainable, and cost-effective materials need to be addressed urgently for the removal of organic pollutants. Herein, ultra-light (0.018 g.cm−3) and highly porous (96.4%) composite aerogel is prepared by gelatinization of graphene oxide with fruit waste-derived cellulose. The macroscopic porosity generated by interconnecting cellulosic skeleton and graphene oxide sheets via hydrogen bonding network provided ample avenues for transport and diffusion of organic dyes-enriched wastewater throughout the cellulose-graphene oxide composite aerogel (CGA). Consequently, organic dyes are efficiently adsorbed by easily accessible surface sites distributed throughout the CGA. The size, charge, and chemical structure of organic dyes along with textural features and accessible surface active sites of CGA governed the adsorption process. The spectroscopic analyses based on FTIR, Raman, and XPS measurements suggest electrostatic, n-π, π-π, cation-π interactions, dipole–dipole hydrogen, and Yoshida hydrogen linkages as major interactive pathways for the adsorption of organic dyes by the CGA. Moreover, the composite aerogel furnished an excellent recyclability for the adsorptive removal of organic pollutants from wastewater. The present work promises the potential of 2D nanostructured layered materials and fruit-waste-derived composite aerogels for sustainable utilization in wastewater treatment, which can be an excellent step towards water security.