Toluene-Containing Gas Stream Treatment by Persulfate-Based Oxidation: Process Variables Affecting Mass Transfer

A toluene-containing gas stream was treated through the application of an activated persulfate-based advanced oxidation process (AOP). As in this type of AOP pollutant degradation is carried out in the liquid phase, the gas-to-liquid mass transfer process is a crucial step to which great attention should be paid, this being the main goal of the present study. A careful analysis of the impact of some parameters on toluene's degradation was performed, investigating (i) the effect of reactor configuration (bubble reactor vs. bubble column reactor with different aspect ratios), (ii) the influence of the type of diffuser (aquarium diffusers, with different geometric shapes, vs. diffuser plates, with different porosities, i.e., with different pore sizes), and (iii) the impact of the water matrix (distilled water vs. tap water). The best treatment performance was achieved when the bubble column reactor and the diffuser plate with higher porosity were used, being indifferent to the type of liquid phase selected, which, from the practical point of view, brings important advantages as tap water can be used without affecting process performance.