DYE AFFINITY POLY(2-HYDROXYETHYL METHACRYLATE) MEMBRANES FOR REMOVAL OF HEAVY METAL IONS

The dichlorotriazinyl dye-ligand Procion Red HE-3B-anchored poly(EGDMA-HEMA) membranes were used for removal of heavy metal ions (i.e., copper, arsenic, cadmium and mercury) from aqueous media containing different amounts of these ions (0.1–4.5 mmol/L) and at different pH values (2.0–8.0). The HE-3B-anchored membranes from their single solutions were 6.4 mmol/m2 for Cu(II), 30.1 mmol/m2 for As(III), 76.3 mmol/m2 for Cd(II) and 130.3 mmol/m2 for Hg(II). When the heavy metal ions competed (in the case of the adsorption from their mixture) the adsorption capacities were 7.8 mmol/m2 for Cu(II), 24.5 mmol/m2 for As(III), 27.6 mmol/m2 for Cd(II) and 42.3 mmol/m2for Hg(II). The same affinity order was observed under non-competitive and competitive adsorption which was as follows: Hg(II) > Cd(II) > As(III) > Cu(II). The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at around pH 5.0. Heavy metal ion adsorption from artificial wastewater was also studied. The adsorption capacities are 4.1 mmol/m2 for Cu(II), 12.5 mmol/m2 for As(III), 16.7 mmol/m2 for Cd(II) and 21.3 mmol/m2 for Hg(II). Desorption of heavy metal ions was achieved using 0.1 M HNO3. The Procion Red HE-3B-anchored membranes are suitable for repeated use for more than 5 cycles without noticeable loss of capacity.