A dielectric barrier discharge based low pressure narrow band far UV-C 222 nm excimer lamp and its efficiency analysis

Abstract

Far UV-C light at wavelength 222 nm is gaining popularity nowadays due to its properties that it cannot penetrate even the outer dead skin of humans and the tear layer of the eyes. This wavelength has been proven to be much safer for human health. In this paper, a dielectric barrier discharge (DBD) based Far UV-C excimer lamp with a very narrow and intense spectrum peaking at a wavelength of 222 nm has been reported. Optimization of high voltage electrodes has been carried out to minimize the lamp heating without using any external cooling. The discharge produced in this configuration is diffused discharge at a low pressure of 140 mbar. Generally, at low pressure, a very wide band of spectra having full-width half maxima (FWHM) of 8-15 nm is obtained. In this case, due to the confined gas gap and bi-polar pulse power arrangements, the spectra obtained are very narrow, having an FWHM of 1.7 nm. Applied voltage, frequency and gas pressure are optimized to get high electrical-to-optical conversion efficiency of the lamp. The measured radiated intensity at the applied input electrical power of 31 W from the optimized lamp is ~ 2.5 mW/cm2, which results in the electrical to optical conversion efficiency as high as 12.5%. The bacterial efficiency of the developed lamp is also examined on pathogenic gram-positive (S. aureus) and gram-negative (E. coli) bacteria. Complete inactivation of S. aureus and E. coli has been achieved at a UV dose of 3 mJ/cm2 and 12 mJ/cm2, respectively. Morphological studies of treated bacteria have also been performed to correlate the results.

Environmentally Friendly UV-C Excimer Light Source with Advanced Oxidation Process for Rapid Mineralization of Azo Dye in Wastewater

“…All of the stock solutions were prepared in deionized (DI) water and artificial wastewater. A mercury-free modified XeI*-excimer UV-C (253 nm) lamp was developed using standard laboratory practices …”

“…A mercury-free modified XeI*-excimer UV-C (253 nm) lamp was developed using standard laboratory practices. 39 2.2. Excimer UV Source Design.…”

Indoor air disinfection by non thermal atmospheric pressure plasma: a comparative study of performance in low and high humidity environments

“…It is reported as an efficient, energy-saving, and environmentally friendly method for removing contaminants [32,33]. In these plasma systems, highly energetic electrons collide with gaseous molecules, leading to ionization and excitation of gaseous molecules, which in turn results in the generation of electrons, radicals, ions, and excited molecules [34,35]. Recently, the use of plasma in conjunction with catalysts, known as plasma catalysis, has garnered a lot of attention for the purposes of air purification and environmental cleanup [36,37].…”