Activated carbon fiber (ACF) enhances the UV/EF system to remove nitrobenzene in water

Abstract

Abstract Activated carbon fiber (ACF) was used to enhance the UV/Electro-Fenton (UV/EF) system to remove nitrobenzene (NB). Comparative removal of NB by ACF adsorption, electrolysis, and UV photolysis was investigated, which indicated ACF can significantly enhance the UV/EF (ACF) system to remove NB. By using ACF cathode, 98% of NB removal was achieved after 20 min, which was much higher than Ti cathode by 60%. The UV/EF (ACF) system was proved to have the feasibility of mineralization of nitrobenzene by the 90% of TOC removal after 5 h. ACF reuse experiments were carried, and the results showed ACF cathode could be reused for successive 4 runs with just 5% declination of NB removal. The impacts of several key influence factors (current intensity, electrolyte, and O2 flux) were explored. Three different kinds of ACF (ACF0: original ACF; ACFN: treated by ammonia; ACFH: treated by nitric acid), methanol, tert-butyl (TBA) alcohol, phenol, and catalase were involved in the system to study the mechanism of the UV/EF (ACF) system. The results showed the combination of ACF and the UV/EF system could significantly improve the H2O2 production and NB removal. Finally, the comparison of the electrical energy per order (EE/O) values between the UV/EF (ACF) and UV/EF (Ti) system showed that ACF can significantly improve the current efficiency of the UV/EF system.