The use of a solid photocatalyst, titanium dioxide, as an amendment incorporated into pavement surfaces was investigated as a basis for controlling nonpoint hydrocarbon runoff. Titanium dioxide is an inexpensive and conservative material that, when activated by sunlight, generates oxygen radicals capable of degrading common hydrocarbon contaminants characteristic of nonpoint highway runoff.
Six materials were evaluated for fixing the photocatalyst onto pavements; paint base and concrete sealant were most effective. A number of contaminants were effectively degraded using the photocatalytic process including hexadecane, anthracene, and 2,4,6 trichlorophenol. Standard procedures (e.g. chloride analysis, addition of scavengers) were used to assess the applicability of photocatalytic pavement borders to a range of waste compounds; the data showed that the process has potential to degrade most compounds present in nonpoint highway runoff. The results of this laboratory study indicated that photocatalytic pavement borders have significant potential for mitigating nonpoint highway runoff.