Heterogeneous photoelectro-Fenton catalyzed by FeCu@PC for efficient degradation of sulfamethazine

Abstract

To improve the mineralization efficiency of heterogeneous electro-Fenton (Hetero-EF), ultraviolet (UV) process and Hetero-EF process were coupled (Hetero-PEF) for degradation of sulfamethazine (SMT) by FeCu@PC (porous carbon) derived from metal-organic frameworks (MOFs). At 60 min, the total organic carbon (TOC) removal and mineralization current efficiency (MCE) of the Hetero-PEF process was 73.3% and 58.7%, which were both 2.23 times that of the Hetero-EF process due to the photoelectric synergy. Moreover, the Hetero-PEF process had wider pH applicability (3.0–7.0) than the Hetero-EF process. This process could also efficiently remove phenol, carbamazepine and 2, 4-D. Through process comparison, quenching and electron paramagnetic resonance (EPR) tests, the reasons for the improvement of mineralization efficiency by Hetero-EF process were disclosed, in which UV not only activated H2O2 to produce •OH but also excited FeCu@PC to form photo-generated electrons to catalyze H2O2 or O2 to •OH and O2•−, respectively. In addition, UV excitation of Fe(OH)2+ and Fe(OOCR)2+ promoted the regeneration of Fe2+, which also greatly enhanced the H2O2 conversion efficiency and mineralization current efficiency. In the five cycles of experiments, the removal efficiency of SMT still reached 97.0%. The FeCu@PC/Hetero-PEF process had the application prospect of highly effective removal of organic pollutants in water treatment.