Sodium chloride removal from urine via a six-compartment ED cell for use in Advanced Life Support Systems (Part 1:: Salt removal as a function of applied voltage and fluid velocity)

A six-compartment electrodialysis cell with univalent ion selective membranes was studied to remove sodium chloride from human urine. Current-voltage behavior data were obtained at four fluid velocities ranging from 0.015 to 0.083 m/s, and four urine dilution ratios ranging from 3,200 to 12,800 ppm, based on chloride salts concentration. Ion chromatography revealed that the highest sodium chloride percentage for continuous once-through mode of operation was of 91.0% achieved at the most diluted solution (U = 0.039 m/s and i = 5 7 A/m(2)). For batch recirculation, the operational voltages were 5.0, 7.5 and 9.0 V and a constant velocity of 0.083 m/s was used. Under this mode of operation the highest removal, 98.5%, was achieved at a potential of 9.0 V.