Micropollutant degradation by the heterogeneous solar photo-Fenton process at circumneutral PH using copper slag

• DOI: 10.1016/j.jwpe.2020.101562
• Publication Date: 2020-08-17T22:05:49Z
• Authors: R. García-Estrada; B. Esteban García; R.M. Ramírez-Zamora; J.A. Sánchez Pérez
• Keywords: Degradation

Abstract This work evaluates the catalytic capacity of a metallurgical copper slag (CS) for the removal of the pesticide Thiabendazole (TBZ) in real wastewater by the heterogeneous photo-Fenton process at circumneutral pH under natural solar irradiation (NSI). The material consists mainly of magnetite and fayalite. The best experimental condition was: 17 mg of CS/cm2, settled at the bottom of the reactor, and 0.44 mM H2O2 illuminated with solar radiation. Under this condition, 80% TBZ degradation (100 μg/L initial spiked concentration) was reached in real WWTP secondary effluent, after 120 min with 50% of H2O2 consumption. The CS-H2O2-NSI system produced 2-fold more hydroxyl radicals (HO•) with respect to the CS-H2O2. The CS-NSI system did not produce HO• radicals, probably due to the fast electron-hole combination reported for one of the iron oxides present in CS, even though it showed a bandgap value of 2.42 eV, which indicates that the material can absorb solar irradiation. Thus, TBZ was oxidized mainly through the heterogeneous photo-Fenton-like reaction, with similar degradation efficiencies after five utilization cycles. This study demonstrates that CS is a chemically stable and efficient Fenton type catalyst for microcontaminant degradation in wastewater.