Development and validation of a simplified kinetic model for predicting organic micropollutant degradation in vacuum ultraviolet water treatment

Vacuum-UV (VUV) advanced oxidation processes (AOPs) show promise for organic micropollutant (OMP) degradation, offering a chemical-free and cost-effective solution. Integrating VUV-AOP with conventional UV/ H2O2 AOP can reduce H2O2 dosing. However, upscaling VUV-AOP faces challenges due to limited VUV photon penetration in water. Kinetic modelling is required to assess the feasibility of VUV AOPs for industrial water matrices. This paper presents a quasi-steady-state kinetic model, balancing simplicity with robustness. The model includes direct photolysis at UV254nm and VUV185nm and oxidation via hydroxyl, chlorine, and carbonate radicals as degradation pathways. The model is calibrated by including or excluding (photo)chemical reactions and simplified using steady-state assumptions for each relevant reactive radical. The model is validated against labscale experiments in Milli-Q (R) water, groundwater, surface water, and tap water matrices for carbamazepine, atrazine, and diclofenac. These compounds have varying degrees of direct photolysis and oxidation rates, thus validating the model's ability to predict their contributions toward organic micropollutant degradation. Surface water and tap water matrices are spiked with various anions the effect of which was well-predicted by the model. The model can be adapted for a computational fluid dynamics platform, accelerating reactor design.