Figure 5.

(a) Permeate mass m as a function of filtration time t for the three different feed pressures p = 0.25 bar (squares), p = 0.75 bar (circles) and p = 1.25 bar (triangles) at ϑ = 22 °C. Each membrane has a slightly different pure water permeability, which is insignificant on the present scale and therefore neglected here. The integrally measured permeate mass m(t) was described empirically by m(t) $\propto$ t^b,integral (lines) [25]. (b) The integral permeability P = J/p depends on the filtration pressure.