Sequential adsorption- dehalogenation removal of PFOA and 2,4,6-TCP with F-CTF as the adsorbent and hydrated electron as the reduction species

Perfluorooctanoic acid (PFOA) and 2,4,6-trichlorophenol (2,4,6-TCP) were typical POPs (Persistent Organic Pollutants) in water. In this study, fluorine-doped covalent triazine framework (F-CTF) was synthesized using an ionothermal method, and the adsorption behavior for PFOA and 2,4,6-TCP on F-CTF was investigated using batch experiments and adsorption kinetic tests. Characterization results showed that the large surface area and abundant pore structure of F-CTF provide a large number of adsorption sites for PFOA and 2, 4, 6-TCP. Batch adsorption tests showed that F-CTF adsorbent exhibited high adsorption affinity to PFOA and 2,4,6-TCP, and the adsorption ability could be described well by the Langmuir adsorption model. The maximum adsorption capacity ( q max ) of F-CTF for PFOA and 2,4,6-TCP reached 262.5 mg/g and 709.2 mg/g, respectively. The adsorption process obeyed the pseudo-second-order kinetics. The adsorption mechanism including electrostatic attraction, hydrophobic interaction, and ion-dipole interaction was further confirmed by pH and ionic strength experiments. Additionally, the UV/Na 2 SO 3 /KI system achieved 100 % degradation rate of PFOA and 2, 4, 6-TCP within 40 minutes and the influence factors were further studied. The e aq − was the main active species for the high reduction of PFOA and 2,4,6-TCP in the UV/Na 2 SO 3 /KI system.