Photochemical removal of acetaldehyde using 172 nm vacuum ultraviolet excimer lamp in N or air at atmospheric pressure.

The photochemical removal of acetaldehyde was studied in N or air (O 1-20%) at atmospheric pressure using side-on and head-on types of 172 nm Xe excimer lamps. When CHCHO was decomposed in N using the head-on lamp (HL), CH, CO, and CO were observed as products in FTIR spectra. The initial removal rate of CHCHO in N was ascertained as 0.

Efficient removal of benzene in air at atmospheric pressure using a side-on type 172 nm Xe excimer lamp.

The photochemical removal of benzene was studied in air at atmospheric pressure using a side-on type 172 nm Xe excimer lamp with a wide irradiation area. After 1.5 min photoirradiation, CH (1000 ppm) in air was completely converted to HCOOH, CO, and CO at a total flow rate of 1000 mL/min.

Photochemical removal of NO(2) by using 172-nm Xe(2) excimer lamp in N(2) or air at atmospheric pressure.

Photochemical removal of NO(2) in N(2) or air (5-20% O(2)) mixtures was studied by using 172-nm Xe(2) excimer lamps to develop a new simple photochemical aftertreatment technique of NO(2) in air at atmospheric pressure without using any catalysts. When a high power lamp (300 mW/cm(2)) was used, the conversion of NO(2) (200-1000 ppm) to N(2) and O(2) in N(2) was >93% after 1 min irradiation, whereas that to N(2)O(5), HNO(3), N(2), and O(2) in air (10% O(2)) was 100% after 5s irradiation in a batch system. In a flow system, about 92% of NO(2) (200 ppm) in N(2) was converted to N(2) and O(2), whereas NO(2) (200-400 ppm) in air (20% O(2)) could be completely converted to N(2)O(5), HNO(3), N(2), and O(2) at a flow rate of 1l/min.