CONCENTRATION AND OR REMOVAL OF METAL-IONS USING A WATER-SOLUBLE CHELATING POLYMER AND A MICROPOROUS HOLLOW-FIBER MEMBRANE

Methods for concentrating and/or removing metal ions from dilute solutions using a water-soluble chelating polymer and a microporous hollow fiber were studied. Experiments were made with a model system of polyacrylic acid and Cu(II). In the once-through mode, where the metal solution flowed inside the fiber immersed in the polymer solution, concentrations of metal ions of as high as 80% in the sample solutions were deionized by use of a fiber of 1.2-m length and 0.8-mm inner diameter. In the circulating mode, where the polymer solution was circulated through the fiber immersed in the sample solution, the metal ions could be recovered from dilute solutions even when concentrations were much lower than those on the recovery side. The overall mass transfer coefficient obtained in this experiment was 10(-6)-10(-5) m/s. The methods reported here were demonstrated to be effective for concentrating and/or removing metal ions from dilute solutions.