Insights into the role of cross-linking agents on polymer template effect: A case study of anionic imprinted polymers

Abstract The template effect is known as the most important feature of ion imprinted polymer (IIP) technology. However, there has been a gap in the theorization of the template effect and apply the template effect to practice. In this work, we propose a method to control the template effect of IIPs by adjusting the ratio of cross-linking. A series of Cr(VI)-IIPs with various contents of the cross-linking agent were synthesized. Based on the qualitative analysis of the coordination selectivity and template effect, the theoretical equation of the template effect generated by the cross-linking agent was established rely on the Scatchard equation. In the Cr(VI) removal process, the contribution of template effect began to surpass the coordination effect when the molar ratio of functional monomer to cross-linking agent was 1/5.46, and the template effect further enhanced with the increase of cross-linking agent content. In the application of actual wastewater treatment, the IIP-1/12 and IIP-1/6 which are designed according to the resulting equation are effective to treat two different types of wastewater. The normalization equations and design concepts proposed in this study theoretically illustrate the role of cross-linking agent in the selectivity of materials. This allows for more flexibility in modulating the template effect of Ion Imprinted Technology for design and application.