DEVELOPMENT OF IMPROVED COUPLED-TRANSPORT MEMBRANES FOR THE RECOVERY AND RECYCLE OF METAL IONS

VAST QUANTITIES OF INDUSTRIAL ACIDS, BASES, PROCESSING SOLUTIONS, AND SLUDGES CONTAIN HEAVY METALS. THESE ARE OFTEN HAZARDOUS, AND IF LEFT UNREGULATED, PRESENT A SERIOUS THREAT TO GROUNDWATER AND THE SURROUNDING ENVIRONMENT. TECHNOLOGIES AVAILABLE FOR TREATING INDUSTRIAL WASTES ARE TYPICALLY INADEQUATE AND EXTREMELY EXPENSIVE. NEW METHODS ARE CLEARLY NEEDED FOR REMOVING TOXIC METALS FROM PROCESS SOLUTIONS AND WASTE SLUDGES--METHODS THAT ARE BOTH EFFECTIVE AND ECONOMICAL. A KEY ASPECT OF WASTE TREATMENT THAT RENDERS IT ECONOMIC IS THE RECOVERY OF VALUABLE COMPONENTS FOR REUSE. BEND RESEARCH HAS DEVELOPED A MEMBRANE-BASED PROCESS CALLED COUPLED-TRANSPORT THAT PROVIDES AN EFFECTIVE MEANS OFSEPARATING AND RECOVERING VALUABLE TOXIC METALS FROM PROCESS SOLUTIONS OR DISSOLVED WASTE SLUDGES. HOWEVER, THE COUPLED-TRANSPORT PROCESS IS CURRENTLY NOT PRACTICAL BECAUSE OF SHORT MEMBRANE LIFETIMES (RANGING FROM A FEW WEEKS TO A FEW MONTHS).