New dye-ligand: Procion Red MX-3B carrying poly(EGDMA-HEMA) microbeads for removal of copper ions

Procion Red MX-3B-attached poly(ethylene glycol dimethacrylate-hydroxy-ethyl methacrylate [poly(EGDMA-HEMA)] microbeads were prepared for removal of Cu2+ ions from aqueous media containing different amounts of Cu2+ ions (2-50 ppm). Procion Red MX-3B-attached microbeads were characterized by FTIR, optical microscopy and elemental analysis. Dye-attached microbeads with a swelling ratio of 55% and carrying 8.95 mu mol Procion Red MX-3B/g polymer were used in the adsorption-desorption of Cu2+ ions. Very high adsorption rates were observed at the beginning of adsorption process and then equilibrium was achieved in about 5-10 minutes. The maximum adsorption of Cu2+ ions onto the Procion Red MX-3B-attached poly(EGDMA-HEMA) microbeads (i.e., by chelate formation of Cu2+ ions with dye molecules) was about 4.6 mg Cu2+ ions/g polymer, which was observed at pH 7.5. Adsorption onto the plain poly(EGDMA-HEMA) microbeads (i.e., non-specific adsorption) was about 0.36 mg Cu2+ ions/g polymer under the same experimental conditions. More than 90% of the adsorbed Cu2+ ions was desorbed in 15 minutes by using 0.1 M HNO3 as an desorption agent.