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Two annular continuous flow reactors with nominal volumes of 400 mL and 150 mL were packed with silica gel pellets that were doped with titania (TiO2) (12 wt%). The reactors were configured with UV lamps in the center of the reactors. SOC oxidation experiments were performed in a single-pass mode with bicarbonate ions present and in a low dissolved oxygen environment. SOC concentrations decreased (ranging from 40% to 95%) without bicarbonate present. These removal efficiencies were not affected by moderate bicarbonate concentrations (up to 200 mg/L as NaHCO3) or low dissolved oxygen levels (2 mg/L). Microbial experiments were performed for the inactivation of selected viruses and bacteria. The log [N0/N] values resulting from two hours of 254-nm UV irradiation for the bacteriophages ФX-174, PRD-1, and MS-2 were 1.67, 1.43, and 1.65, respectively.

A prototype reactor was designed and tested to oxidize synthetic organic chemicals (SOCs) without the use of expendable chemicals and without the need to separate the catalyst from the water after treatment. An annular continuous flow reactor with a nominal volume of 400 mL was packed with silica gel pellets that were doped with titania (TiO2) (12 wt%). The reactor was configured in a test stand with UV lamps in the center of the reactor. SOC oxidation experiments were performed in a recycle mode and in a single-pass mode. Five target analytes (acetone, chlorobenzene, ethyl acetate, toluene, and methylmethacrylate) were spiked (100 to 300 μg/L) into nano-pure water and recycled through the reactor until adsorption equilibrium was attained. UV lamps, which were shielded, were then uncovered, and effluent concentrations were monitored as a function of time. All of the compounds were degraded to below detection limit (5 μg/L) after an extended reaction period of 23 hours.