2.2. Membranes production
According to the methodology previously published [3], a 5%wt solution of PAN in N,N-dimethylformamide had been produced and then electrospun on a rotating collector. After a suitable amount of fibres had been collected, electrospinning was stopped and electrospraying of the proper catalytic system suspension was performed. Three different kind of membranes had been obtained varying the photocatalyst/co-photocatalyst system spread over the nanofibers surface according to the outline presented in Fig. 1, wherein all the steps involved during each membrane type production are reported. The details of the electrosprayed suspensions are the following:
a)
TiO2, 5% w/w in ethanol, 40 min ultrasonication (VibracCell 200 W, amplitude 40%) and dispersant agent addition, according to [16].
b)
Few-layer graphene suspension 0.25% w/w in ethanol, 20 min ultrasonication, addition of 1% w/w of SDS with respect the solvent weight, followed by 15 min sonication.
c)
TiO2/graphene nanocomposite suspension, obtained by the aforementioned hydrothermal method, properly stabilized by dispersant agent addition (1% w/w SDS).