Comparison of Falling-Film and Glass-Tube Solar Photocatalytic Reactors for Destroying Toxic Organic Chemicals in Water.

摘要

Photocatalytic destruction of a model compound has been demonstrated with bench scale and with two engineering scale experiments. For the engineering scale experiments two solar concentrating hardware systems were used: a glass-tube/trough system and a falling-film/heliostat. The ultraviolet (uv) power on the reactors of the bench scale, glass-tube/trough and falling film/heliostat systems were 0.15, 1600, and 5200 watts of uv. In the bench scale experiments, the use of hydrogen peroxide as an oxidant with a titanium dioxide catalyst under ultraviolet illumination yielded reaction rates an order of magnitude greater than without the oxidant. The thermal performances of both solar systems are favorable for photocatalytic processes, since mineralization of the contaminant can take place before boiling occurs. The trough/glass tube system was evaluated in clear and partly cloudy weather, and the amount of time to attain the same level of destruction was proportional to the total incident solar energy. With the heliostat/falling film system, experiments were performed at two upper levels. The concentration of the model compound was reduced below detectable limits in less than 30 seconds of exposure. Preliminary data indicate initial reaction rates are linear with ultraviolet intensity, though further experimental studies will need to be performed to verify this relation. 17 refs., 8 figs. (ERA citation 14:024295)