Photodegradation of Carbamazepine and Acridine with 165-200 nm Radiation from a Microcavity-Plasma VUV Phosphor Lamp

Investigatingthe potential of a new microcavity-plasmalamp with a phosphor wavelength converter film for advanced watertreatment. A longstandingobstacle to the application of vacuum ultraviolet(VUV) radiation for advanced water treatment is the absence of efficient,affordable, and powerful lamps. A custom Xe-2 microcavityplasma (McP) lamp with an internal phosphor film, generating broadbandemission in the 165-200 nm interval, is presented here as anoptical source for the degradation of dissolved contaminants. Theperformance of this lamp was evaluated by comparing measured photodegradationrates for carbamazepine (CBZ, a model compound) with correspondingdata obtained with a conventional 254/185 nm Hg lamp. While the oxidantproduction rate was lower for the McP lamp, it was found to be moreeffective in photodegrading CBZ for a given energy dosage absorbedby the water. The McP lamp also produced higher concentrations ofthe byproduct acridine (ARD) but normalization to effective fluenceexposure reveals it produced and removed ARD more efficiently thandid the Hg lamp. The flat form factor and ability to produce outputpowers >10 W from a 100 cm(2) aperture make the McP lamppromising for photochemical water treatment. Although its emissionspectrum is not currently optimized, the data indicate that the lampspectrum can be engineered to efficiently photodegrade a wide rangeof challenging water pollutants.