简介: |
This talk covers two areas of membranes for water purification: (1) the removal and recovery of heavy metals from waste waters by supported liquid membranes (SLMs) with strip dispersion and (2) water purification by interfacially polymerized reverse osmosis membranes. New membrane technology based on SLMs with strip dispersion for the removal and recovery of metals, including chromium, copper, zinc, strontium, and cobalt from waste waters has been developed. The technology not only removes the targeted metal in the treated effluent allowable for discharge or recycle, but also recovers the metal at high concentration and purity suitable for resale or reuse. In other words, the goals of zero discharge and no sludge have been achievable. The SLMs contain selected complexing agents/carriers for the facilitated transport of the target species. The stability of the SLM has been ensured by engineering the modified SLM with strip dispersion. The SLMs have also shown great potential for antibiotic recovery. For interfacially polymerized reverse osmosis membranes, the state-of-the-art membranes in the thin-film-composite (TFC) structure prepared by interfacial polymerization are reviewed and discussed. Recent developments have been on high flux TFC interfacially polymerized membranes. Both the processing steps in membrane formation consisting of glycerol dip and drying and the use of additives (monohydric phenols) in the aqueous amine solution during interfacial polymerization have improved water flux significantly. The membranes have shown >100% increase in water flux vs. the industry standard Film-Tec FT-30 membrane while maintaining a high NaCl rejection of >99%. The high flux membranes can yield high water productivity and can have significant energy saving for desalination. Initial scale-up of the membrane to commercial size has been successful. |