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Published: 1991

Total Pages: 8

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Solar energy is being applied to one of the most difficult environmental problems our country faces in the coming decades: the destruction of hazardous waste. DOE Researchers are developing two separate technologies -- solar detoxification of water and solar decontamination of soil -- that could revolutionize the way toxic wastes are removed from the environment. Unlike many remediation techniques in use today, these solar-based processes actually destroy hazardous contaminants; the wastes are not transferred to other media for disposal. Solar detoxification of water uses solar energy to power a reaction that eliminates organic contaminants from polluted surface water and groundwater. The process uses a solar-activated photocatalyst, such as titanium dioxide, to break the bonds holding organic compounds together. Researchers are currently working to increase the efficiency and reduce the costs of the process to make it economically competitive with traditional remediation methods. In a related program researchers are investigating the ability of high solar flux (upwards of 300 times the sun's normal intensity) to decontaminate polluted solids such as soils. The solar decontamination of soil is a two-step process: in the first step contaminants are desorbed from the solid either by solar thermal energy or by conventional means (such as heating or vacuum extraction); in the second step the desorbed contaminants are destroyed. The contaminants can be destroyed by using either a high-flux photolytic process or a low-flux process that employs a photocatalyst. SERI's state-of-the-art high-flux solar furnace is home to a large portion of the soil decontamination research. 4 figs.