Removal of mixed pollutants of perfluorooctanoic acid and 2,4,6-trichlorophenol via adsorption-photocatalysis using Ga2O3-Bi4O7 combining with fluorine-doped covalent triazine framework: Role of different active species

• Published in: Journal of colloid and interface science 2024-12, Vol.676, p.959-973
• Main Authors: Wang, Shuyun, Wang, Siyuan, Tang, Rong, Liu, Yin, Chen, Huan
• Format: Article
• Language: English
• Subjects: 2,4,6-TCP; Adsorption-photocatalysis; Dechlorination; Defluorination; Ga2O3-Bi4O7/CTF; PFOA
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.07.188

[Display omitted] •GaBi/CTFx were used for adsorption-photocatalytic treatment of PFOA and 2,4,6-TCP.•F-CTF provides adsorption sites and promotes photogenerated carrier separation.•·O2– and ·OH account for 2,4,6-TCP degradation, while h+ is for PFOA degradation.•Different characteristics of pollutants enhance utilization of active species. Perfluorooctanoic acid (PFOA) and 2,4,6-trichlorophenol (2,4,6-TCP) are significant pollutants found in textile wastewater, posing severe threats to ecological environments. The construction of an adsorption-photocatalytic system enables the efficient removal of mixed pollutants by harnessing their synergistic effect, thereby overcoming the limitations of removing mixed pollutants with single water treatment technologies. Herein, fluorine-doped covalent triazine framework (F-CTF) was combined with Ga2O3-Bi4O7 heterojunction to obtain Ga2O3-Bi4O7/F-CTF (GaBi/CTF). F-CTF greatly facilitates the adsorption process and provides convenience for photocatalysis. Simultaneously, the excellent conductivity of F-CTF promoted the separation of photoinduced charge carriers in Ga2O3-Bi4O7. GaBi/CTF5 (5 is the mass percentage of F-CTF) showed excellent degradation performance, and the removal rates of PFOA and 2,4,6-TCP reached 93.0 % and 100.0 % within 90 min, respectively. Mechanistic analysis revealed that 2,4,6-TCP and PFOA were attacked by distinct active species because of the disparate characteristics. The presence of phenolic hydroxyl groups makes 2,4,6-TCP more vulnerable to superoxide radicals (·O2–) and hydroxyl radicals (·OH), whereas PFOA is oxidized by holes (h+). The coexistence of mixed pollutants with diverse characteristics enables optimal utilization of active species generated within photocatalytic system. Moreover, the good stability of GaBi/CTF5 provides a feasible solution for efficient treatment of mixed pollutants in textile wastewater.