Congo Red-Attached Poly(EGDMA-HEMA) Micro beads for Removal of Heavy Metal Ions

Abstract

Abstract In this study we investigated a new sorbent system, Congo Red-attached poly (EGDMA-HEMA) micro beads, for removal of heavy metal ions from aqueous solutions. Poly(EGDMA-HEMA) micro beads were prepared by suspension copolymerization of ethylene glycol di methacrylate (EGDMA) and hydroxyethyl methacrylate (HEMA) by using poly(vinyl alcohol), benzoyl peroxide, and toluene as the stabilizer, the initiator, and the diluent, respectively. Congo Red molecules were then covalently attached to these micro beads. Micro beads (150–200 o in diameter) with a swelling ratio of 55% and carrying 14.5 omol Congo Red/g polymer were used in the adsorption/desorption studies. Adsorption rate and capacity of the micro beads for selected metal ions, i.e., Cd(II), Cu(II), Zn(II) and Pb(II), were investigated in aqueous media containing different amounts of these ions (1–500 ppm) and at different pH values (1.5–7.5). Very high adsorption rates were observed at the beginning, and adsorption equilibria were then gradually...