Engineering a Pulsed UVA-LED/Persulfate System Guided by Parrondo’s Paradox for Efficient Degradation of Emerging Pharmaceutical Pollutants and Electrical Energy Optimization

The increasing occurrence of emerging pharmaceutical pollutants in aquatic environments poses serious ecological and public health concerns, including the proliferation of antibiotic-resistant bacteria. This study introduces a novel and energy-efficient approach employing Controlled Pulsed Illumination (CPI) to enhance the performance of UV-based advanced oxidation processes (AOPs) for pollutant degradation. The effects of pulse periods and duty cycles on the trade-off between removal efficiency and energy consumption are systematically evaluated, with energy performance expressed as electrical energy per order ( E EO, kWh m –3 .order –1 ). A comparative assessment of three treatment pathways, namely, persulfate alone (PS), UVA irradiation alone, and their combination (UVA/PS), confirms the superior reactivity of the hybrid system. Under optimized CPI conditions (75% duty cycle, 100 ms pulse period), the hybrid UVA/PS process achieved a 55.87 ± 2.65% removal efficiency within 60 min while reducing E EO from 1034.36 to 760.37 kWh m –3 .order –1 . Degradation kinetics followed a pseudo-first-order model, indicating mechanistic consistency across configurations. Optimized pulsed irradiation reduces radical recombination, thereby improving the effective utilization of reactive species. These findings highlight the practical potential of pulsed irradiation for optimizing AOP performance and introduce a paradoxical illumination strategy, inspired by Parrondo’s paradox, to destabilize persistent pharmaceutical pollutants. Overall, this work paves the way for sustainable and energy-efficient water treatment technologies with practical applicability.