Paper EH-MoE4
Graphene Oxide-cellulose Nanocrystal Sponge as a Tunable Platform for Contaminant and Pathogen Removal from Water

Monday, December 3, 2018, 6:40 pm, Room Naupaka Salon 6-7

Graphene oxide (GO) sponges are a new class of sorbents for removal of a diverse range of contaminants from water. The immobilization of GO in a solid porous macrostructure eliminates the requirement for removal of the otherwise stable colloidal GO from the treated water. Unlike colloidal GO, solid macrostructures can be easily stored, transported and manipulated. Although much progress has been made on forming high surface area and multifunctional GO sponges, synthesizing mechanically robust multifunctional sponges, especially in wet state, is a challenge. We report the preparation of an ultrastrong GO-based sponge strengthened with cellulose nanocrystal (CNCs) – natural nanorods isolated from wood pulp – using a green synthesis method with the aid of excess vitamin C (VC). VC acts as a natural reducing agent, whereas CNCs provide a scaffold that links the reduced GO (rGO) nanosheets together, resulting in an exceptionally stiff nanocomposite. During sponge synthesis, undissolved excess VC grains act as soft templates, yielding nanocomposites with hierarchical pore architecture, even in the core of large sponges as confirmed by micro and nano X-ray tomography. The use of ultra-large GO nanosheets, as well as the interconnected hierarchical pore structure translate into sponges with a high specific surface area and large removal capacity for a wide range of contaminants such as dyes, heavy metals, and pharmaceuticals. The GO-CNC sponges exhibit excellent contaminant removal from single and multicomponent waters, in batch and continuous removal modes. Additionally, we show that the sponges of this study can be readily functionalized with antimicrobial peptides and biopolymers to enhance removal and inactivation of bacteria from contaminated water supplies.