Reactive Green HE-4BD functionalized supermacroporous poly(hydroxyethyl methacrylate) cryogel for heavy metal removal

摘要

The aim of this study was to investigate the heavy metal adsorption performance of supermacroporous poly(hydroxyethyl methacrylate) PHEMA cryogel. The PHEMA cryogel was produced by cryo-polymerization. The PHEMA cryogel was characterized by scanning electron microscopy (SEM). The PHEMA cryogel containing 385 lmol Reactive Green HE-4BD/g were used in the adsorption studies. Adsorption capacity of the PHEMA cry-ogel for the metal ions, i.e., Cu ~(2+), Cd~(2+), and Pb~(2+) were investigated in aqueous media containing different amounts of the ions (5-600 mg/L) and at different pH values (3.2-6.9). The maximum adsorption capacities of the PHEMA cryogel were 11.6 mg/g (56 μmol/g) for Pb~(2+), 24.5 mg/g (385 μmol/g) for Cu~(2+) and 29.1 mg/g (256 μmol/g) for Cd~(2+). The competitive adsorption capacities were 10.9 mg/g (52 μmol/g) for Pb ~(2+), 22.1 mg/g for Cd~(2+) (196 μmol/g) and 23.2 mg/g (365 μmol/g) for Cu~(2+). The PHEMA/Reactive Green HE-4BD cryogel exhibited the following metal ion affinity sequence on molar basis: Cu ~(2+) > Cd~(2+) > Pb~(2+). The PHEMA/Reactive Green HE-4BD cryo-gel can be easily regenerated by 50 mM EDTA with higher effectiveness. These features make the PHEMA/Reactive Green HE-4BD cryogel a potential adsorbent for heavy metal removal.