含氟富氮多孔有机聚合物的合成及其对水中全氟辛酸的去除OA北大核心CSTPCDMEDLINE

Perfluorooctanoic acid(PFOA)is a persistent contaminant with detrimental effects on the natural environment.This persistence leads to potential enrichment and osmotic trans-fer,which can affect normal circulation in the environment.PFOA poses significant threats to both the natural environment and human health.Therefore,the development of cost-effective,highly efficient,and environment-friendly PFOA adsorbents is a crucial endeavor. This paper presents the catalyst-free one-pot synthesis of fluorinated nitrogen-rich porous or-ganic polymers(POP-3F)via a Schiff-base condensation reaction.The reaction between the ni-trogen-rich compound 1,4-bis(2,4-diamino-1,3,5-triazine)benzene and p-trifluoromethylbenzal-dehyde yielded POP-3F.The introduction of fluorine atoms into the nitrogen-rich porous organic polymer enhanced its hydrophobicity,thereby facilitating favorable fluoro-fluorine interactions with PFOA and,thus,improving the efficacy of the adsorbent.Scanning electron microscopy(SEM),Fourier transform infrared(FT-IR)spectroscopy,X-ray diffraction(XRD),solid-state nuclear magnetic resonance(ssNMR)spectroscopy,X-ray photoelectron spectroscopy(XPS),nitrogen adsorption-desorption analysis,and thermogravimetric analysis(TGA)were used to confirm the successful synthesis and characterization of POP-3F. Liquid chromatography-tandem mass spectrometry(LC-MS/MS)was conducted in negative electrospray ionization(ESI)mode coupled with multi-reaction monitoring mode(MRM).The instrument was equipped with an Atlantis T3 column(100 mm×2.1 mm,3 pm),and analysis was conducted using an external standard method.The influences of various factors on PFOA adsorption by POP-3F,including pH,salt concentration,and humic acid presence,were inves-tigated.The highest PFOA removal rate(98.6％)was achieved at a pH of 2,indicating the ap-plicability of POP-3F for the effective removal of PFOA from acidic industrial wastewater.The removal rate of PFOA was unaffected by increases in NaCl concentration.This phenomenon can be attributed to electrostatic interactions between the protonated secondary amines in POP-3F and deprotonated PFOA.Upon the addition of NaCl,a double electric layer is formed on the POP-3F surface,with Cl-ions in the outer layer and Na+ions in the inner layer,which weak-ened these interactions.Humic acid is competitively adsorbed with PFOA.However,POP-3F demonstrated good removal rates even in the presence of high humic acid concentrations in wa-ter.Adsorption isotherm and kinetics experiments were conducted at the optimal pH to explore the relevant adsorption mechanism.The results showed a rapid initial adsorption rate,with 95.4％PFOA removal within 5 min.Optimal adsorption equilibrium was achieved within 6 h,and the removal rate decreased by only 0.3％after 24 h.This finding indicates that POP-3F ex-hibits sustained efficacy for PFOA removal.Langmuir fitting analysis revealed a theoretical max-imum adsorption capacity of 191 mg/g for POP-3F;this value surpasses those of activated car-bon materials and most other adsorbents,highlighting the superior PFOA-adsorption perform-ance of POP-3F.Additionally,matrix effects minimally affected the removal of PFOA by POP-3F,with only a slight reduction(0.1％)observed in simulated natural water.The recyclability of POP-3F was assessed over five adsorption-desorption cycles.The removal efficenecy exhibi-ted a minor decrease of only 0.67％after five cycles.These results demonstrate the recyclability of the proposed adsorbent,which translates into cost reduction through reusability.This char-acteristic renders POP-3F a promising candidate for the economical and efficient removal of PFOA from waste water in practical applications.