Synthesis And Characterization Of Fomesafen Imprinted Polymers

A series of molecularly imprinted polymers(MIPs) for fomesafen were developed via precipitation polymerization employing methacrylic acid as functional monomer, ethylene dimethacrylate as cross-linker, acetonitrile as porogen and azobisisobutyronitrile as initiator at different conditions.The effect of different molar ratios, the solvent and the crosslinking agent on the properties of the polymers were investigated. The results showed that when the molar ratio of template: monomer: crosslinking agent with 1: 4: 20 and the acetonitrile as the porogen, the prepared MIP2 have the best property.Equilibrium adsorption experiments show that under the same adsorption capacity, the adsorption capacity of MIP2 was higher than the corresponding non-imprinted polymer(NIP2). Scatchard equation displayed that MIP2 have two affinity sites, the Qmax and Kd of the high affinity sites of MIP2 were 16.94 mg ? g-1 and 208.33 mg ? L-1, respectively. The Qmax and Kd values of NIP2 were 5.38 mg ? g-1 and 42.55 mg ? L-1, respectively. The results of Scatchard analysis showed that adsorption for fomesafen of MIP2 derived from specific adsorption, adsorption for fomesafen of NIP2 came from the non-specific adsorption.Binding capacity experiment showed that MIP2 had the highest binding capacity of 3.25 mg·g-1 and the best specific affinity with imprinting factor(α) =1.53.The adsorption process for fomesafen could be divided into two steps,a quick step and a slow one. In the first step, the adsorption rate was fast, and the binding equilibrium was almost reached within 20 min.In the subsequent step,the adsorption process was slow to reac-h equilibrium,and the final capacities for adsorption of fomesafen onto MIP2 and NIP2 were 3.25 and 2.12 mg·g-1, respectively. In kinetic adsorption experiment like equilibrium binding, MIP2 had more binding capacity than NIP2,indicating that there were specific binding sites for fomesafen.Morphology and structure of MIP2 and NIP2 were characterized by scanning electron microscopy and fourier transform infrared spectroscopy. The results showed that the morphology of the polymer is good, template was wrapped in the polymer.