Adsorption of heavy metal ions onto ethylene diamine-derived and Cibacron Blue F3GA-incorporated microporous poly(2-hydroxyethyl methacrylate) membranes

Microporous poly( 2-hydroxyethylmethacrylate) (PHEMA) membranes carrying et hylene diamine (EDA) and Cibacron Blue F3GA were prepared for the removal o f heavy metal ions (i.e. mercury, copper, lead and cadmium) from aqueous so lutions containing different amounts of these ions (5-700 mu g 1(-1)) and a t different pH values (2.0-8.0). The non-specific adsorption of heavy metal ions on the underived membranes was very low (3.3 mmol/m(2) for Hg(II), 0. 5 mmol/m(2) for Cu(II), 1.2 mmol/m(2) for Pb(II) and 1.1 mmol/m(2) for Cd(I I)). Cibacron Blue F3GA attachment significantly increased the heavy metal adsorption (16.3 mmol/m(2) for Hg(II), 19.9 mmol/m(2) for Cu(II), 23.4 mmol /m(2) for Pb(II) and 38.4 mmol/m(2) for Cd(LI)). When the heavy metal ions competed (in the case of the adsorption from a mixture) the adsorption capa cities were 7.1 mmol/m(2) for Hg(II), 17.9 mmol/m(2) for Cu(II), 6.2 mmol/m (2) for Pb(II) and 9.1 mmol/m(2) for Cd(lI). The observed order in adsorpti on was found to be Cd(II) > Pb(II) > Cu(II) > Hg(II) for non-competitive co nditions. The adsorption of heavy metal ions increased with increasing pH a nd reached a plateau value at around pH 5.0. Desorption of heavy metal ions was achieved using 0.1 M HNO3. These membranes are suitable for repeated u se for more than five cycles without considerable loss of adsorption capaci ty. (C) 2000 Elsevier Science B.V. All rights reserved.