Simulation and optimization of the removal of toluene in air by ozonation with a catalytic open-cell foam

Abstract

A heterogeneous catalyst, composed of an open-cell glass foam support impregnated with zerovalent ruthenium nanoparticles (loading around 0.1 wt.%), was used to remove toluene in air by catalytic ozonation. Experiments with lab-designed 2−6 cm length and 1.6 cm diameter catalysts were performed. A model based on the Langmuir–Hinshelwood mechanism, coupled with mass transfer limitations and including competitive effects between toluene and ozone, was designed. It accurately fits experimental data gathered at various temperatures (30−90 °C), gas velocities (0.0025−0.017 m s−1) and inlet ozone concentrations (6.4–11.2 g m−3). The removal of ozone and toluene was mainly ruled by the ozone concentration at low concentrations while the adsorption competition becomes significant at high ozone concentrations.Predictive simulations, at 1.0 g m−3 inlet toluene concentration, were compared in terms of investment cost, operating cost and process performances. The results highlighted the complexity of the process, which involves antagonist aims between toluene removal and the design of a compact and energy-efficient reactor. With the best operating conditions (90 °C and 46 g m−3 ozone inlet concentration), the removal of toluene reached 88% (removal rate of 0.25 g m−3 s−1) with a high ozone degradation (97%) in a moderate reactor length of 0.11 m. These good performances associated to the low cost of the catalyst’s synthesis make it an efficient alternative for the removal of pollutants from air.