Preparation of novel magnetic ethylene glycol dimethacrylate-based molecularly imprinted polymer for rapid adsorption of phthalate esters from ethanol aqueous solution

Phthalate esters (PAEs), as emerging pollutants, pose a serious threat to human health and have become a major concern in the fields of environmental protection and food safety. Selective adsorption using molecularly imprinted polymer (MIP) is feasible, but most MIPs use the potentially toxic methacrylic acid (MAA) as a functional monomer, along with other crosslinking agents. In this study, MIP adsorbent was prepared using only ethylene glycol dimethacrylate (EGDMA) as both the functional monomer and crosslinking agent, without the inclusion of MAA. The adsorbent was utilized for the adsorption of PAEs from an ethanol aqueous solution. The results showed that EGDMA-based MIP (EMIP) achieved better adsorption performance of PAEs than MAA-based MIP (MMIP) due to more interactions of EGDMA with PAEs than MAA with them. For the adsorption of dibutyl phthalate (DBP) using EMIP, 95% of the equilibrium adsorption capacity was achieved within the first 15 min. In the isotherm analysis, the theoretical maximum adsorption capacity of EMIP was obtained as high as 159.24 mg/g at 20 °C in an ethanol (10 v%) aqueous solution. Furthermore, the adsorption of EMIP was not affected by the pH of the solution. The adsorption process of EMIP followed the pseudo-second-order kinetic and Freundlich isotherm model. Ethanol had a significant impact on the adsorption of DBP, and the results of molecular simulation could validate this. In addition, the regeneration experiments indicated that EMIP could be recycled 5 times without significant performance change and had a high recovery efficiency of 94.55%.