Figure 1
From: Low cost, high performance ultrafiltration membranes from glass fiber-PTFE–graphene composites
(A) SEM image of the edge of a glass fibre (GF) membrane. (B,C) TEM images of typical LPE graphene nanosheets (B) and PTFE nanoparticles (C). (D) Lateral size distribution for both graphene nanosheets and PTFE nanoparticles. (E) Photographs of GF membrane (top left) and membranes with a range of nominal PTFE/graphene contents. The number reflects the graphene content in the soak solution expressed as CG/(CG + CP) where CG and CP are the concentrations of graphene and PTFE in the soak solutions. (F) The membranes are soaked in a dispersion of PTFE nanoparticles with the mass uptake plotted versus the concentration of PTFE (soak time 45 min). The dashed line represents linearity. Inset: SEM images of a GF membrane partially filled with PTFE. (G,H) GF membrane partially filled with PTFE and graphene where CG/(CG + CP) = 33% (G) and 74% (H). (I,J) Graphs showing fractional mass uptake on soaking for two soaking scenarios: (I) The membranes are soaked in a dispersion of both PTFE nanoparticles and graphene nanosheets with CP = 10 mg/ml and varying CG. The mass uptake is plotted versus the combined concentration of PTFE and graphene (soak time 45 min). The dashed line represents a linear increase in mass uptake with CG. Inset: Mass uptake poltted as a function of CG/(CG + CP) showing a clear power law dependence. (J) The membranes are soaked in a dispersion of both PTFE nanoparticles and graphene nanosheets with CP = 10 mg/ml, CG = 8.8 mg/ml for varying soak times. The dashed line represents what would be expected if the uptake was solely diffusion limited.
