Abstract

This study presents a solar-driven photocatalytic treatment system for decentralised water remediation evaluated under real outdoor conditions. A TiO₂-based photocatalyst operated in a 5 L compound parabolic collector (CPC) reactor was assessed using a combination of field Analytical modelation and irradiance–performance analysis. Real-time global horizontal irradiance (260–910 W m⁻²) showed a strong linear relationship with apparent degradation kinetics (R² = 0.84–0.88), demonstrating that photocatalytic activity was primarily governed by photon availability under natural sunlight. Under peak solar conditions, removals of 92 ± 4% atrazine, 86 ± 6% imidacloprid, and 79 ± 5% sulfamethoxazole were achieved within 60 min. To examine operational optimisation, treatment performance was analysed against concurrent irradiance data to identify efficient operating windows. Based on this relationship, an irradiance-gated operational strategy was estimated to increase daily pollutant throughput by approximately 32% compared with fixed-schedule operation
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Analytical models using natural river water showed a 20–35% decrease in removal efficiency, attributed to increased turbidity and dissolved organic matter that attenuate light penetration and compete for reactive species
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Overall, the results demonstrate the feasibility of solar CPC photocatalysis for decentralised treatment of agricultural runoff and highlight the importance of irradiance-responsive operation for improving process efficiency under variable sunlight.