Researchers studied methods for concentration and removeing metal ions from waste effluent using a water soluble chelating polymer and a microporus hollow fiber membrane. Tests emplyacrylic acid (molecular weight 90,000) that was adjusted to pH 5 with soduim hydroxide, and a microporous hollow fiber membrane composed of polyacrylonitrile fibers with a thickness of 0,3 millimeter and an inner diameter of 0,8 millimeter. Sample effluent consisted of copper (II) ions in aqueous suspension. The once through methodm, in which the effluent flowed inside the microporus hollow polyacrlonitirile fibers as they were immersed in the polymer solution, succeeded in deionzing the metal ions at concentrations as high as 80 percent by weight. The circulating method, in which the polymer solution was circulated thorugh the microporus hollow polyacryonitrile fibers as they were immersed in the effluent, failed to deionize the metal ions even at drastically lower concentrations. 6. refs.