THE INFLUENCE OF PHOTOCATALYTIC DEGRADATION CONDITIONS OF PARACETAMOL AND DICLOFENAC USING TiO2 AND ZnO
DOI:
https://doi.org/10.58407/bht.1.26.17Keywords:
photocatalysis, pharmaceutical pollutants, catalyst, paracetamol, diclofenac, degradationAbstract
Purpose of the work. To investigate the photocatalytic degradation of paracetamol (PAR) and diclofenac (DCF) in aqueous solutions under the action of zinc oxide (ZnO) and titanium dioxide (TiO2); to determine the influence of pH and catalyst dosage on the degradation rate; and to compare the efficiency of different photocatalytic systems.
Methodology. To determine the optimal conditions for the photocatalytic processes, the following parameters were investigated: the effect of the pH of the working solutions and the concentrations of the catalysts. Degradation was carried out under UV irradiation, and the process was modelled using pseudo-first-order kinetics. Based on experimental data, reaction rate constants (k) and half-life periods (t1/2) were calculated for each set of conditions.
Scientific novelty. For the first time, a comparative analysis of PAR and DCF degradation under identical conditions using two of the most widespread photocatalysts – ZnO and TiO2 – was conducted, enabling the identification of differences in their reactivity toward distinct classes of pharmaceutical pollutants. The study established regularities in the influence of pH on the photocatalytic activity of TiO₂ and ZnO for both PAR and DCF, demonstrating a clear trend: lowering pH enhances degradation more significantly for TiO2 than for ZnO. It was found that TiO2 exhibits substantially higher activity in acidic media, enabling nearly complete PAR removal even at a catalyst concentration of 0.5 g/dm3, which provides a basis for optimizing photocatalytic wastewater treatment conditions. Differences in the kinetic behaviour of the two pollutants were identified: PAR consistently degraded faster than DCF under all experimental conditions, indicating variations in molecular stability and reactivity during photocatalytic processes.
Conclusions. PAR degraded faster than DCF regardless of the photocatalyst type. The highest degradation efficiency was achieved with TiO2 in acidic medium (pH 5), while ZnO showed moderate activity. Lowering pH and increasing catalyst dosage intensified the degradation of pharmaceutical compounds.
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Copyright (c) 2026 Олена Кізюн, Валерій Зажигалов, Ігор Умнов, Інна Трус
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