Figure 12: Time dependence of the permeate flux obtained with the (a) ESP04, (b) PU608 and (c) Kerasep Nano NF membranes, operating at selected transmembrane pressures (○ – 2 bar; ■– 4 bar; ♦ – 6 bar; □ – 8 bar; “filled triangle” – 10 bar; ● – 12 bar; Δ – 14 bar) during the processing of raw autohydrolysis liquors. Feed velocity, 2 m/s for the UF membranes and 3 m/s for the NF membrane, 26 ± 4°C), [1].