Cysteine functionalized poly(hydroxyethyl methacrylate) monolith for heavy metal removal


UZUN L., TÜRKMEN D., Yilmaz E., Bektas S., DENİZLİ A.

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, vol.330, pp.161-167, 2008 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 330
  • Publication Date: 2008
  • Doi Number: 10.1016/j.colsurfa.2008.07.045
  • Journal Name: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.161-167
  • Keywords: Heavy metal removal, Monoliths, Environmental pollution, ADSORPTION PROPERTIES, COMPLEXING LIGAND, AQUEOUS-SOLUTIONS, CADMIUM REMOVAL, BEADS, IONS, CHROMATOGRAPHY, MICROBEADS, CELLULOSE, SUPPORTS

Abstract

The aim of this study was to investigate the performance of monoliths composed of hydroxyethyl methacrylate (HEMA) to which N-methacryloyl-(L)-cysteine methyl ester (MAC) was polymerized for removal of heavy metal ions. Poly(HEMA-MAC) monolith was produced by bulk polymerization. Poly(HEMA-MAC) monolith was characterized by FTIR and scanning electron microscopy (SEM). The poly(HEMA-MAC) monolith with a swelling ratio of 89%, and containing 69.4 mu mol MAC/g were used in the adsorption studies. Adsorption capacity of the monolith for the metal ions, i.e., Cu(2+), Cd(2+), Zn(2+), Hg(2+), and Pb(2+) were investigated in aqueous media containing different amounts of the ions (10-750 mg/L) and at different pH values (3.0-7.0). The maximum adsorption capacities of the poly(HEMA-MAC) monolith were 68.2 mg/g for Zn(2+), 129.2 mg/g for Cu(2+), 245.8 mg/g for Pb(2+), 270.2 mg/g for Hg(2+) and 284.0 mg/g for Cd(2+). pH significantly affected the adsorption capacity of MAC incorporated monolith. The competitive adsorption capacities were 587 mu mol/g for Zn(2+), 1646 mu mol/g for Cu(2+), 687 mu mol/g for Pb(2+), 929 mu mol/g for Hg(2+) and 1993 mu mol/g for Cd(2+). The chelating monolith exhibited the following metal ion affinity sequence on molar basis: Cd(2+) > Cu(2+) > Hg(2+) > Pb(2+) > Zn(2+). The formation constants of MAC-metal ion complexes have been investigated applying the method of Ruzic. The calculated values of stability constants were 5.28 x 10(4) L/mol for Cd(2+), 4.16 x 10(4) L/mol for Cu(2+), 2.27 x 10(4) L/mol for Hg(2+), 1.98 x 10(4) L/mol for Pb(2+), and 1.25 x 10(4) L/mol for Zn(2+). Stability constants were increased with increasing binding affinity. The chelating monoliths can be easily regenerated by 0.1 M HNO(3) with higher effectiveness. These features make poly(HEMA-MAC) monolith a potential adsorbent for heavy metal removal. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.