Removal of Cu(II), Zn(II), Cd(III) and Hg(II) from waste water by poly(acrylaminophosphonic)-type chelating fiber

The distribution coefficients (D) for Cu(II), Cd(II), Zn(II) and Hg(II) ions and adsorption isotherms of Cd(II) and Hg(II) ions on the poly(acrylaminophosphonic)-type chelating fiber were investigated using the batch reactor system. It was found that D values for the tested metal ions were above the magnitude of 103 at pH 5.0, and the order of metal ion affinities was: Hg(II) > Cu(II) > Zn(II) > Cd(II). At low pH value (2.0), D value for Hg(II) ion was higher than that of the other ions, above 103. The adsorption of Hg(II) and Cd(II) ions on the new chelating fiber followed a Langtnuir-type adsorption isotherm. The elution of the metal ions from the chelating fiber column using dilute nitric and hydrochloric acid as eluent were examined. The results show that the elution for Cu(II), Cd(II) and Zn(II) ion was complete using appropriate concentration of hydrochloric acid, while the high concentration of dilute nitric acid was necessary for the quantitative desorption of fig(II) ion. The breakthrough curves for the metal ions were determined, and the efficient removal of the listed metal ions from model or waste water by the newly developed fibrous sorbent was achieved.