Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation

Tsunehiro Maehara, Kyohei Nishiyama, Shingo Onishi, Shinobu Mukasa, Hiromichi Toyota, Makoto Kuramoto, Shinfuku Nomura, Ayato Kawashima

doi:10.1016/j.jhazmat.2009.09.076

Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation

説明

The degradation of methylene blue by radio frequency (RF) plasmas in water under ultraviolet (UV) irradiation was studied experimentally. When the methylene blue solution was exposed to RF plasma, UV irradiation from a mercury vapor lamp enhanced degradation significantly. A lamp without power supply also enhanced degradation since weak UV light was emitted weakly from the lamp due to the excitation of mercury vapor by stray RF power. Such an enhancement is explained by the fact that after hydrogen peroxide is produced via the recombination process of OH radicals around the plasma, OH radicals reproduced from hydrogen peroxide via the photolysis process degrade methylene blue.