Volume 7, No. 1, March 2007, Pages 79-94 PDF(339 KB)
Application of Soft X-rays in the Decomposition of Polycyclic Aromatic Hydrocarbons (PAHs) in Smoke Particles from Biomass Fuel Burning
Yunhe Bai1, Masami Furuuchi1, Perapong Tekasakul2, Surajit Tekasaku3, Thitiworn Choosong1, Masaya Aizawa1, Mitsuhiko Hata1, Yoshio Otani1
1 Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
2 Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
3 Department of Chemistry, Faculty of Science 90112, Prince of Songkla University, Hat Yai, Songkhla, Thailand
Soft X-rays with a wave length of 1.3 × 10-4 – 4.1 × 10-4 m were tested for use in studying the decomposition of polycyclic aromatic hydrocarbons (PAHs), widespread hazardous and carcinogenic pollutants that are emitted during biomass burning. Both size-fractionated and -unfractionated smoke particles, after irradiation by the soft X-rays, were collected on quartz-fiber filters using two different residence times through the irradiating zone to determine the effect of the soft X-ray irradiation on particle-bound PAH concentration. Smoke particles produced by rubberwood burning had a single modal size distribution consisting of fine particles less than 2 m and a large mass fraction of PAHs in particles that were about 5 times higher than the urban ambient particles. The PAHs in the rubberwood smoke were decomposed by soft X-ray irradiation up to about 30%, essentially independent of the duration of the irradiation (0.022-0.067 sec) and with a slight dependence on the boiling temperature of each PAH composition. From the irradiation test for the size fractionated particles, PAHs in finer fraction particles were found to be decomposed more effectively. Soft X-rays have the potential for use as an effective device for pollution control.
PAHs; Decomposition; Biomass burning; Irradiating duration; Particle size; Rubberwood.