Alternative Treatment Technologies

TiO₂ Photocatalytic Destruction — Matrix Photocatlytic Inc.

The TiO₂ (titanium dioxide) Photocatalytic Destruction is a process that uses the energy of ultraviolet light to accelerate the breakdown of chlorinated compounds at the surface of the titanium dioxide catalyst.

Contaminated air is passes through a fixed TiO₂ catalyst bed in a series of reactor cells called wafers, each of which is comprised of six cells. Each reactor cell is housed in an outer stainless steel jacket that contains the photocatalytic matrix wrapped around a quartz sleeve and a UV lamp. The UV light interacts with the TiO₂ semi-conductor material to produce highly reactive chemical species, hydroxyl radicals, which are capable of destroying chlorinated compounds in the vapor phase.

The National Renewable Energy Laboratory (NREL) demonstrated the Matrix Photocatalytic titanium dioxide (TiO₂) based system at McClellan AFB. On average the system satisfactorily removed TCE and cis-l,2-DCE from the vapor stream, however it did not meet the Sacramento Metropolitan Air Quality Management District's “best available control technology” requirement of 95 percent removal removal for PCE, chloroform, carbon tetrachloride, and 1,2-DCA. For a more complete description of the test results at McClellan AFB and a test at Savannah River please see MatrixPCORprt.htm

Figure 1: Photograph of full-scale photocatalytic air treatment system adapted from USEPA SITE program.