Microwave Discharge Electrodeless Lamps (MDELs). Part XI. Photolytic, Chemical Oxidation, and Photocatalytic Treatment of Aqueous Urea Solution with a Novel MDEL Photoreactor

Abstract

Decomposition of urea in aqueous solution was carried out using a microwave discharge electrodeless lamp (MDEL) consisting of two photoreactors with a triple tube structure that generate vacuum-UV/UV light and reactive oxygen species (ROS) using microwaves (MW) as an energy source. The rate of decomposition of urea was highest under acidic conditions (pH 4) compared with those at pH 7 and 10. When used in combination with dispersed TiO₂, a photocatalyst, high decomposition efficiency was achieved with less power consumption. Moreover, decomposition efficiency more than two times higher than that of ozone oxidation and sodium hypochlorite oxidation could be realized.