Conductive electrospun nanofibers containing cellulose nanowhiskers and reduced graphene oxide for the electrochemical detection of mercury(II)

Mercury is a heavy metal highly deleterious for the environment being associated to several diseases. Thus, novel and expedite techniques capable of detecting this heavy metal in water, even at trace levels, are highly sought for human and environmental safety purposes. Here we developed a novel electrochemical sensor for detecting mercury(II) using a green hybrid nanoarchitecture composed of reduced graphene oxide (rGO), cellulose nanowhiskers (CNW) and polyamide 6 (PA6) electrospun nanofibers. Scanning transmission electron microscopy (STEM), ultraviolet-visible (UV-VIS) absorption and Fourier transform infrared (FTIR) spectroscopies and termogravimetric analysis (TGA) were employed to elucidate the morphology and composition of CNW:rGO hybrid system. The hybrid composite proved to enhance charge transference properties, which was evaluated by cyclic voltammetry (CV) experiments. Due to the excellent electrical properties of graphene, the nanocomposite (PA6/CNW: rGO) was applied in the electrochemical detection of very low concentrations of mercury in water samples, improving the sensor sensibility. Moreover, the PA6/CNW/rGO electrode demonstrated stability, high selectivity, low detection limit and wide dynamic linear range for the detection of mercury(II).