Figure 5
From: Low cost, high performance ultrafiltration membranes from glass fiber-PTFE–graphene composites
(A) Photograph of water collected from the Grand Canal in Dublin before filtration (left), after filtration through a glass fibre membrane (middle) and after filtration through a CG/(CG + CP) = 20% GF/PTFE/graphene membrane (ΔM/MGF ~ 1.3%, right). (B–D) Impurity metrics as measured by a commercial water purity testing firm for the three water samples in (A). In (B), turbidity is a measure of visible light scattering and is commonly used to indicate the presence of impurities in water. The unit used is the Nephelometric Turbidity Unit (NTU). In (C), C. perfringens is a bacterium which is a common cause of food poisoning while coliforms are a bacteria group, which are a commonly used indicator of water quality. The number of C. perfringens is reported in colony forming units (CFU) while the number of coliforms is reported as the most probable number (MPN). The solid lines in (B,D) represent the recommended limits set by the WHO and the EU. In (D) the graphene-based membrane data was below the Fe detection limit of the experiment (dashed line) as indicated by the arrow. In (D), both the GF and graphene-based membrane data were below the C. perfringens detection limit while the graphene-based membrane datum was below the coliforms detection limit as indicated by the arrows (detection limit shown as dashed line).
