Ultrasonic-enhanced Cu(I)/Cu(II) nanointerfaces for sustainable ozone activation in green aluminum production: Atomic-level catalysis of organic waste degradation

The accumulation of refractory organics in Bayer liquor (pH 14.4) critically compromises aluminum production efficiency and product quality, necessitating sustainable remediation strategies. Herein, we develop an ultrasonic-driven catalytic ozonation system with dynamically reconstructed CuO/Cu 2 O heterointerfaces, achieving unprecedented efficiency in extreme alkaline wastewater treatment. Atomic-scale interface engineering endows the catalyst with hydrophilicity (contact angle: 6.1°) and 3.8-4.3 times higher oxygen vacancy density compared to single-phase catalysts. These properties facilitate efficient interfacial interactions with Bayer liquor and enable superior ozone activation through synergistic Cu(I)/Cu(II) redox cycling across the heterointerface. This interfacial synergy reduces ozone adsorption energy from 5.46 eV (Cu 2 O) to 1.48 eV, driving reactive oxygen species (ROS) generation via low-energy pathways. Under optimized conditions, the system achieves 57.82% TOC removal within 1.5 h with 2.3-fold faster kinetics than ozone-alone processes, while improving energy efficiency by 1.82-3.22 times per kWh over conventional thermal oxidation. Remarkable stability is demonstrated through 80.21% activity retention after 6 cycles, attributed to surface energy minimization (0.61 J/m 2 ), alongside 67.91% hydroxyl radical ( • OH)-mediated degradation confirmed by quenching tests. In XPS, EEMs analysis, and ECOSAR modeling further elucidate the surface reconstruction mechanism and intermediate toxicity reduction. This work establishes an atomic interface design paradigm that bridges catalytic innovation with green metallurgy applications, offering a sustainable solution for industrial wastewater remediation aligned with circular economy principles. An ultrasonically activated catalytic ozonation system featuring an atomically engineered Cu(I)/Cu(II) heterointerface catalyst was developed. This system enables efficient degradation of organic pollutants in extremely alkaline industrial Bayer liquor, thereby paving the way for sustainable aluminum metallurgy processes. • Ultrasonic Cu(I)/Cu(II) heterointerface enables 57.8% TOC removal in pH 14.4 media. • 3.22-fold energy efficiency gain vs thermal/pressure-driven oxidation. • Cu(I)/Cu(II) heterointerface lowers O 3 adsorption energy (5.46 eV vs 1.48 eV) • 80.21% catalytic activity retained after 6 cycles under cavitation.