Removal of inorganic ions by polymer-based colloid-enhanced membrane filtration in aqueous solution

The removal of inorganic ions in the aqueous phase was investigated using systems of colloids of metal hydroxide, water-soluble polymer and colloid-enhanced polymer with the help of membrane filtration. The results show that only 50 mg/l of phosphate were completely retained by Fe(III) colloids at pH 4.0 in the aqueous phase, whereas from a solution containing 5000 mg/l phosphate, 80% were removed by water-soluble poly(ethyleneimine), or 92% by Fe(III) colloid-enhanced poly(ethyleneimine) under the same conditions, respectively. Cations such as Cd(II), Cu(II), Co(II), Cr(III), Ni(II), Pb(II), Zn(II) were nearly quantitatively removed from the aqueous solution.