Studies on the synergistic effect within a carrier-bound TiO2/UV/O3 system in the degradation of chlorinated SVOCs from real groundwater

Groundwater quality faces many anthropogenic threats from industry, mining, agricultural and urbanization. This study presents an integrated advanced oxidation process (AOP) to remediate industrial contamination in an actual groundwater system, detailing the required test rig configurations and analytical techniques. A carrier-bound TiO₂/UV/O₃ system was employed to degrade chlorinated semi-volatile organic compounds (SVOCs) within a pump-and-treat configuration. The oxidative decomposition of multiple dichloro- and chloronitrobenzene isomers, along with their corresponding chlorinated anilines, was systematically investigated to determine dependencies on key process parameters. Process control analyses revealed a pronounced synergistic effect of ozone on photocatalytic oxidation in the combined AOP, surpassing the efficiencies of isolated ozonation or photocatalysis. For 3,4-dichloronitrobenzene, the combined system achieved up to 31 % higher degradation efficiency in a miniaturized AOP laboratory reactor, although kinetic studies deviated from a pseudo-first-order reaction model. The developed process effectively reduces both chlorinated volatile organic compounds (VOCs) and SVOCs at real industrially contaminated sites without additional chemicals, with the only continuous input being electrical current for ozone generation and UV LED activation. Owing to its compact design, chemical self-sufficiency, and robust oxidative capacity, the TiO₂/UV/O₃ AOP is well-suited for decentralized, space-efficient groundwater treatment at industrially impacted sites.