Cu(OH)NO/γ-AlO catalyzes Fenton-like oxidation for the advanced treatment of effluent organic matter (EfOM) in fermentation pharmaceutical wastewater: The synergy of Cu(OH)NO and γ-AlO.

The secondary effluent of fermentation pharmaceutical wastewater exhibits high chromaticity, elevated salinity, and abundant refractory effluent organic matter (EfOM), presenting significant treatment challenges and environmental threats. Herein, Cu(OH)NO/γ-AlO was fabricated through ultrasound-assisted impregnation and calcination to catalyze the Fenton-like oxidation for degrading organic pollutants in this secondary effluent. Under neutral conditions, with 400.00 mg/L HO, 8 g/L catalyst, and at 30 ℃, the EfOM and COD removal efficiencies can reach 96.90 % and 51.56 %, respectively. The Cu(OH)NO/γ-AlO catalyst possesses ideal reusability, maintaining COD, chromaticity, and EfOM removal efficiencies at 44.44 %-64.59 %, 85.45 %-93.45 %, and 61.00 %-95.00 % over 220 h in a continuous-flow catalytic oxidation system operated at room temperatures (15-25 ℃). Electron paramagnetic resonance results and density functional theory calculations indicate that •OOH may be the predominant reactive oxygen species, facilitated by the easier elongation of the OH bond in HO compared to the OO bond. The adjusted electronic structure endows Cu(OH)NO/γ-AlO composite sites with superior catalytic selectivity for HO activation compared to Cu(OH)NO single crystal sites, with γ-AlO additionally facilitating HO activation through electron donation. This research highlights the efficacy of Cu(OH)NO/γ-AlO in the advanced treatment of complex industrial wastewater, elucidating its catalytic mechanisms and potential applications.