Development of a Hg-free UV light source incorporating a Kr/Br2 gas, and its application for wastewater treatments

Mercury lamps are typically the major light sources in water treatments. However, use of mercury has raised some concerns with regard to Minamata Convention on Mercury. As such, Hg-free microwave discharged electrodeless (MDELs) that incorporate a rare gas and halogen (R/H-MDEL) have been investigated such mixture filler gases as Kr/Cl2, Xe/Cl2, Kr/Br2 (R/H). Of these, only Kr/Br2-MDEL lamp is self-ignited at an inner pressure 15 Torr when irradiated radiation. Accordingly, novel three-layer MDEL (Kr/Br2-MDEL) photoreactor was fabricated assess optimal composition toward its performance vis-à-vis treatment model wastewaters contaminated tartrazine dye aqueous media Escherichia coli (E. coli) bacteria. The extent degradation sterilization E. increased irradiation time, radiation power (100, 200, 300 W), sample flow rate 0.4 L min?1 0.8 min?1. tartrazine-contaminated wastewater treated for 60 min by three different protocols resulted UV (62%) >> UV/ROS (24%) > ROS (0%); denotes reactive oxygen species. After 5 E.coli wastewater, also min?1, order (99.5%) ? (99.3%) (14.5%). For comparison, photosterilization equivalent Hg/Ar-MDEL source nearly complete (99.7%). Thus, suitability environmentally friendlier fill replace Hg/Ar MDELs photoelimination organic pollutants microbial disinfection demonstrated.