Reuse of Industrial Waste Water by Electrodialytic Extraction of Heavy Metals through POROPLASTIC (Trade Name) Bound Liquid Ion Exchange Membranes. Phase 2

摘要

Heavy metal salt contamination often hinders industrial waste water reuse due to the marginal economic attractiveness of present reuse technology for industries not yet impacted by diminishing water resources. By combining modern coupled-ion-transport, electrodialysis and bound-liquid membrane extraction techniques, the work described in this report has developed a process for selective removal of heavy metal salts from a dilute waste stream. The combined process relies on pH-driven ion transport through membranes impregnated with ion with exchange liquids, the driving pH in turn generated by membrane mediated water splitting electrodialysis. This approach appears to be both more efficient and more versatile than conventional electrodialytic transport. No chemical reagents are required and no harmful byproducts introduced. The system, not yet optimized appears viable for lead, copper, mercury and cadium at fluxes of 50 to 100 micrograms/sq cm/min from dilute waste streams. Experimental results at 4 to 5 volts are presented, along with investigation of ion exchange selectivities for divalent ions in the presence of larger amounts of monovalent salts.