Anti-fouling graphene-based membranes for effective water desalination.

The inability of membranes to handle a wide spectrum of pollutants is an important unsolved problem for water treatment. Here we demonstrate water desalination via a membrane distillation process using a graphene membrane where water permeation is enabled by nanochannels of multilayer, mismatched, partially overlapping graphene grains. Graphene films derived from renewable oil exhibit significantly superior retention of water vapour flux and salt rejection rates, and a superior antifouling capability under a mixture of saline water containing contaminants such as oils and surfactants, compared to commercial distillation membranes. Moreover, real-world applicability of our membrane is demonstrated by processing sea water from Sydney Harbour over 72 h with macroscale membrane size of 4 cm2, processing ~0.5 L per day. Numerical simulations show that the channels between the mismatched grains serve as an effective water permeation route. Our research will pave the way for large-scale graphene-based antifouling membranes for diverse water treatment applications.

Multifunctional graphene micro-islands: Rapid, low-temperature plasma-enabled synthesis and facile integration for bioengineering and genosensing applications.

Here, we present a rapid, low-temperature (200°C) plasma-enabled synthesis of graphene micro-islands (GMs). Morphological analyses of GMs by scanning electron microscopy (SEM) and atomic force microscopy (AFM) feature a uniform and open-networked array of aggregated graphene sheets. Structural and surface chemical characterizations by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) support the presence of thin graphitic edges and reactive oxygen functional groups. We demonstrate that these inherent properties of GMs enable its multifunctional capabilities as a bioactive interface. GMs exhibit a biocompatibility of 80% cell viability with primary fibroblast lung cells after 5 days. Further, GMs were assembled into an impedimetric genosensor, and its performance was characterized by electrochemical impedance spectroscopy (EIS). A dynamic sensing range of 1pM to 1nM is reported, and a limit of quantification (LOQ) of 2.03×10-13M is deduced, with selectivity to single-RNA-base mismatched sequences. The versatile nature of GMs may be explored to enable multi-faceted bioactive platforms for next-generation personalized healthcare technologies.