Ion‐imprinted PHEMA based monolith for the removal of Fe³⁺ ions from aqueous solutions

Molecular recognition based Fe 3+ imprinted monolith was prepared for selective removal of Fe 3+ ions from aqueous solutions. The precomplexation was achieved by the coordination of Fe 3+ ions with N ‐methacryloyl‐( L )‐cysteine methyl ester (MAC) to form the complex monomer (MAC‐Fe 3+ ). The polymerization step was then carried out in the presence of MAC‐Fe 3+ complex and hydroxyethyl methacrylate (HEMA) monomer by bulk polymerization to constitude a Fe 3+ ‐imprinted polymer (PHEMAC‐Fe 3+ ). The specific surface area of PHEMAC‐Fe 3+ 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 0.1 M EDTA solution. The maximum adsorption capacity of PHEMAC‐Fe 3+ monolith for Fe 3+ 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‐Fe 3+ monolith was 59.7 and 37.0 times greater than that of the nonimprinted PHEMAC monolith as compared with the Cd 2+ and Ni 2+ ions, respectively. The PHEMAC‐Fe 3+ monolith was recovered and reused many times without any significant decrease in its adsorption capacity.