Ion-Imprinted PHEMA Based Monolith for the Removal of Fe3+ Ions from Aqueous Solutions

Abstract

Molecular recognition based Fe3+ imprinted monolith was prepared for selective removal of Fe3+ ions from aqueous solutions. The precomplexation was achieved by the coordination of Fe3+ ions with N-methacryloyl-(L)-cysteine methyl ester (MAC) to form the complex monomer (MAC-Fe3+). The polymerization step was then carried out in the presence of MAC-Fe3+ complex and hydroxyethyl methacrylate (HEMA) monomer by bulk polymerization to constitude a Fe3+-imprinted polymer (PHEMAC-Fe3+). The specific surface area of PHEMAC-Fe3+ monolith was found to be 35.2 m(2)/g, with a swelling ratio of 60.2% after the template was removed from the monolith by 0.1M EDTA solution. The maximum adsorption capacity of PHEMAC-Fe3+ monolith for Fe3+ ion was 0.76 mg/g. The adsorption behavior of the monolith has been successfully described by the Langmuir isotherm. It was determined that the relative selectivity of PHEMAC-Fe3+ monolith was 59.7 and 37.0 times greater than that of the nonimprinted PHEMAC monolith as compared with the Cd2+ and Ni2+ ions, respectively. The PHEMAC-Fe3+ monolith was recovered and reused many times without any significant decrease in its adsorption capacity