双模板分子印迹聚合物制备及其对有机磷农药选择性识别OA

The simultaneous recognition and adsorption of multiple target pollutants by conventional dual-template molecularly imprinted polymers(MIPs)is often severely compromised by competition between different template molecules for the same recognition sites,yielding reduced adsorption efficiency and poor selectivity.To address this critical issue,this study proposed a novel strategy based on spatially isolated recognition sites.Using chlorpyrifos(CPF)and methyl parathion(MP)as dual templates,along with polystyrene-b-polyacrylic acid and β-cyclodextrin as mesoporous and microporous porogens,respectively,a hierarchically porous dual-template molecularly imprinted polymer(HpDt-MIPs)was fabricated via a stepwise imprinting method.The morphology,porous structure,and chemical composition of the resulting polymer were thoroughly characterized via transmission electron microscopy,Brunauer-Emmett-Teller surface area analysis,and Fourier-transform infrared spectroscopy.The characterization results revealed that the HpDt-MIPs possessed a bimodal pore size distribution with distinct peaks at 0.7 and 2.1 nm,and exhibited a high specific surface area of 387.2 m2/g.The adsorption performance was systematically evaluated under various conditions.Equilibrium adsorption experiments conducted at 318 K demonstrated that the HpDt-MIPs achieved outstanding adsorption capacities of 230.29 and 222.39 mg/g for CPF and MP,respectively.Moreover,the CPF and MP imprinting factors were as high as 12.32 and 10.74,respectively,indicating exceptional specific recognition ability for both target molecules.This remarkable adsorption selectivity was attributed to the spatially separated imprinting sites,which were derived from the distinct pore-forming agents,and the stepwise imprinting strategy,which effectively eliminated mutual interference between the two templates.These results demonstrated that the proposed hierarchically porous architecture with spatially isolated recognition sites not only resolved the long-standing competition problem for dual-template MIPs but also significantly enhanced their binding capacity and selectivity.This study provides a promising material design paradigm for the efficient enrichment and separation of multiple target pollutants in complex environmental and food matrices,which may be widely applied in sample pretreatment and sensing.