BACKGROUNDPhotolytic and photocatalytic oxidation processes were used as pretreatments for the purpose of producing more soluble and easily degradable byproducts that were subsequently treated in a biofiltration system for VOC treatment. n-Hexane was chosen as a model hydrophobic VOC, and ZnO was used as a photocatalyst. RESULTSThe potential of this technology was evaluated at an inlet load of 200gm(-3)h(-1) and a residence time of 94.2s for the coupled system. The results showed that the photocatalytic pretreatment had a greater impact on the removal of hexane than the photolytic pretreatment with elimination capacities (EC) of 43gm(-3)h(-1) and 24gm(-3)h(-1), respectively. The EC of hexane and the CO2 production reached in the coupled system increased by at least 20%. This behavior was directly related to the high biodegradability of byproducts produced in the photocatalytic system, such as alcohols and ketones. CONCLUSIONPhotocatalytic oxidation used as a pretreatment system for hexane vapors using ZnO as photocatalyst enabled the generation of byproducts with high solubility that could be easily degraded in subsequent biological treatment. (c) 2014 Society of Chemical Industry