Fig. 3.

Nanofiltration for separation and recovery of oxalic acid from a sugar containing aqueous phase from the OrganoCat process (see also Fig. 1 and [36]). a Permeate flux in dependency of the permeate yield for different total concentrations. b Retention of glucose, xylose, and oxalic acid for different sugar concentrations. Conditions: Desal DL nanofiltration membrane in a stirred 1.4 lL dead-end filtration cell, 0.015 m² membrane area, 40 bar, 300 rpm