Removal, Separation, and Recovery of Heavy Metals from Industrial Wastestreams Using Molecular Recognition Technology (MRT)

摘要

All Navy, Army, and Air Force industrial wastewater treatment plants (IWTPs) receive 90% by volume of metal laden waste waters from electroplating, parts cleaning and paint stripping operations. Treatment of industrial waste waters using the conventional hydroxide precipitation method generates hazardous metal sludge, which is sent to landfill as RCRA F006 hazardous waste. With increasing potential for out of compliance violations (ref. 1) under the Metal Products and Machinery (MP&M) Rule-40 CFR Part 438, Naval Facilities Engineering Service Center (NFESC) was tasked by the Office of Naval Research(ONR) to develop and demonstrate innovative industrial wastewater treatment technologies. This effort was part of a Tri-Service program to evaluate advanced techniques to effectively recycle/reclaim metals from industrial wastewaters (ref. 2). An industrial process was sought that would selectively recover heavy metalions and not retain the benign alkaline earth metal ions such as Na+ and K+ or alkali metal ions Mg2+ or Ca2+. In 1995, a NFESC published the results of feasibility testing of three novel metal adsorption technologies (ref. 3). One of these metal adsorption technologies, for which IBC Advanced Technologies, Inc., holds patents, met the Navy s treatment requirements for heavy metal recovery/recycle from acid/alkali cleaning process wastewaters and chromium plating rinse waters. This metal recovery process is based on the use of synthetic chemical compounds called macrocyclic ligands, a concept that received the 1987 Nobel Prize in chemistry (ref. 4). These highly selective macrocyclic ligands will complex with heavy metals ions and have very weak interactions with benign alkaline earth or alkali metal ions. The term, molecular recognition has been applied to macrocyclic ligands that are capable of single metal ion selection.