Selective Removal Of BPA From Contaminated Water Using Molecularly Imprinted Polymers Based On Graphene Oxide Fe₃O₄ Composites

In recent years, BPA have drawn considerable attention because of the a dverse effects on the endocrine systems of human and wildlife even at extremely low concentration. Thus far, a large number methods have been available for the re moval of BPA from environmental. However, Because of its highly resistant to chemical degradation and biodegradable, conventional municipal wastewater treatment plants are partially inefficient in removing. Additionally, these techniques cannot selectivity removal of BPA from complex matrix, which limited their further application. In this research, a novel magnetic molecularly polymers（MMIPs） based on graphene oxide/Fe₃O₄ composites were successfully synthesized for the selective recognition and fast removal of BPA from aqueous solutions. The main contents are summarized as follows:（1）The molecular imprinting polymers were prepared by adopting the novel surface molecular imprinting technique with GO-Fe₃O₄ as a carrier material, BPA as the template, methacrylic acid（MAA） as the functional monomer, ethylene glycol dimethacrylate（EDMA） as the crosslinker, azoisobutyronitrile（AIBN） as initiator and dimethyl sulfoxide（DMSO） as solvent. As a reference, the magnetic non-imprinted polymers were also using the same synthetic protocol but in the absence of the template. The structure, composition and morphology of GO-Fe₃O₄/MMIPs were studied by various characterizations such as FTIR 、SEM、XRD and VSM. Results showed that the imprinted film was coated on GO-Fe₃O₄ surface and the GO-Fe₃O₄/MMIP had a Ms value of 6.33 emu g-1, which provided an efficient way to separate pollutants from extreme environments.（2） The prepared GO-Fe₃O₄/MMIP and GO-Fe₃O₄/MNIP were applied to removal of BPA from aqueous solutions. The experimental parameters such as p H value, equilibration time, re action temperature, initial concentration of BPA and ionic strength on the adsorption of BPA were investigated. Results showed largest adsorption capacity of GO-Fe₃O₄/MMIPs were 472.68 mg/g at 298 K. And the optimum reaction conditions of the adsor ption process as follows: the o p t im u m reaction time is 40 min, the optimum p H is 6. In addition, selective recognition experiment was performed by using 2,4-DCP and phenol as competitive compounds, and the selectivity coefficients for the experiment were 1.02 and 1.01, respectively. The result revealed that the GO-Fe₃O₄/MMIP have good applicability to selective recognition and fast removal of BPA from aqueous solution.（3） Adsorption kinetics, Adsorption isotherm and Scatchard analysis were adopted to demonstrate and explain the adsorption selectivity of the GO-Fe₃O₄/MMIP towards target molecule. It may concluded that there were two kinds of different binding sites existed in GO-Fe₃O₄/MMIP. The pseudo-second-order equation well described the adsorption of BPA on the MMIPs, indicating chemical process could be the rate-limiting step in the adsorption process for BPA. Langmuir isotherm model was fitted to the equilibrium data better than the Freundlich model.（4） The research found that the adsorption capacity of GO-Fe₃O₄/MMIPs which used five times remained no changes, the prepared GO-Fe₃O₄/MMIPs had broad application prospects.