Polymer - clay nanocomposite iron traps based on intersurface ion-imprinting

We combined the ion-imprinting technique and the binding ability of Fe ³⁺ ions to organosmectite to create the inorgano-organo Fe ³⁺ ions imprinted polymer-nanocomposite traps with the goal of preparing a solid phase that has high selectivity for Fe³⁺ ions. In the first step, the intercalation of quartamine cations was conducted by an ion-exchange process between the smectite host and an aqueous quartamine solution and Fe3+ ions were complexed with methacryloylamidoantipyrine (MAAP). In the second step, quartamine cations were exchanged with a preorganized metal-chelate complex monomer for the preparation of polymer nanocomposite traps based on the intersurface ion-imprinting. After that, the template ions (i.e., Fe³⁺) were removed using 4.0 M HNO₃ solution. Fe ³⁺-imprinted nanocomposites were characterized by Fourier transform infrared (FTTR), X-ray diffraction (XRD), swelling studies, and elemental analysis. Maximum binding capacity, optimum pH, and equilibrium binding time were found to be 78.5 mg/g, pH 3.0, and 10 min, respectively. The relative selectivity coefficients of the imprinted nanocomposite traps for Fe ³⁺/Al³⁺, Fe³⁺/Cu²⁺, Fe³⁺/ Co²⁺, and Fe³⁺/Zn²⁺ were 5.28, 11.4, 15.8, and 72.6 times greater than the nonimprinted nanocomposites, respectively. The Fe³⁺-imprinted nanocomposite traps could be used many times without decreasing in their adsorption capacities significantly.