Validation of a two-dimensional modeling of an externally irradiated slurry photoreactor

A two-dimensional model describing the behavior of a batch cylindrical photoreactor has been validatedthrough a series of photocatalytic reactivity runs. The light intensity radiation field produced by 1–6 external UV fluorescent lamps was modeled together with Langmuir–Hinshelwood kinetics and 4-nitro-phenol (NP) and Degussa P25 TiO 2 were used as the probe molecule and the catalyst, respectively. Theexperiments were carried out under different conditions of light intensity, photocatalyst amount andsubstrate concentration. The model parameters were the kinetic constant of substrate adsorption,desorption and degradation and the exponent of the power law expressing the kinetics dependence onthe light intensity. A least-squares best fitting procedure was used to fit the experimental data to themodel and find the four required parameters. A satisfactory agreement was obtained between experi-mental and calculated values of the observed pseudo-first order kinetic constant, with a coefficient ofdetermination R2 = 0.83. Notably, the present model is of general interest for cylindrical slurry photore-actors, where different molecules can be oxidized in the presence of several photocatalysts and it can beused, for instance, to accurately compare the performance of a set of catalysts.