Graphene Oxide-Chitosan Aerogels: Synthesis, Characterization, and Use as Adsorbent Material for Water Contaminants

Abstract

Porous aerogels, formed by subjecting precursor hydrogels using a freeze-drying process, are certainly one of the most studied and synthetized soft materials, thanks to their important features such as elasticity, swelling behavior, softness, and micro and nanosized pores, which guarantee their applicability in various fields. Typically, these systems are synthetized working with natural or synthetic polymers, but in the last years great interest has been given to proper formulated aerogels able to combine polymeric structures with other moieties such as graphene or graphene oxide. This working strategy can be pivotal in many cases to tune important properties of the final system such as toughness, porosity, elasticity, electrical conductivity, or responsive behavior. In this work we propose the synthesis of chitosan graphene oxide aerogels obtained through self-assembly of graphene oxide sheets and chitosan chains. These three-dimensional systems were chemically characterized with IR and XRD technique and their inner structure was investigated through the scanning electron microscopy (SEM). Moreover, we mechanically characterized the material through dynamic mechanical analysis, showing the stability of these systems. Finally, the adsorption ability of these soft materials has been demonstrated using model molecules to simulate water contaminants showing the efficacy of those graphene-based systems even for the removal of anionic dyes. Complete removal of contaminants was obtained at low concentration of dyes in solution (100 mg/L), while with a higher amount of pollutant in the solution (350 mg/L) high sorption capacity (q > 200 mg/g) was observed.

Porous Aerogel Structures as Promising Materials for Photocatalysis, Thermal Insulation Textiles, and Technical Applications: A Review

“…Due to the difference in water vapor pressure at the surface and in the surroundings, moisture is exchanged between the two surfaces. The net amount of moisture exchange between these two surfaces affects vapor pressure as well as thermal conductivity [124,125]. Furthermore, during the service life of SA-TIMs, vapor phase transport (convection and diffusion), liquid phase transport (wicking), heat transfer (convection, conduction, and radiation), liquid evaporation and condensation, and sorption/diffusion of water vapor and liquid through the solid phase occur.…”

Emerging Trends in Nanotechnology: Aerogel-Based Materials for Biomedical Applications

“…Pineli et al created a graphene oxide/chitosan aerogel by cross-linking graphene oxide sheets via chitosan chains using APS. Electrostatic interactions between positive chitosan charges and negative functional groups of graphene oxide were observed to be increased [ 68 ]. Gong et al also said that chemical cross-linking improved the mechanical performance of chitosan/graphene oxide aerogel [ 69 ].…”

A perspective on graphene based aerogels and their environmental applications

“…As explained above, the GBAs can be produced by different methods that leads to final materials with enhanced properties such as high electrical conductivity, high mechanical strength, thermal stability and high adsorption capacity for dyes, oils, organic solvents, and inorganic ions. Thus, the GBAs can be exploited in a whole range of applications, and they have become increasingly employed especially for environmental pollution control and monitoring, such as water treatment [68] and pollution degradation [69,70]. The other advantage that makes GBA so interesting in environmental applications is the reusability and the recyclability of these materials [71,72].…”