Enhanced photocatalytic oxidation of gaseous elemental mercury by TiO2 in a high temperature environment.
The photo-oxidation of Hg(0) in a lab-scale reactor by titanium dioxide (TiO2) coated on the surface of glass beads was investigated at high temperatures. TiO2 was calcinated at four different temperatures of 300 °C, 400 °C, 500 °C and 600 °C (noted as Ti300, Ti400, Ti500 and Ti600) and characterized for its physicochemical properties. The calcinated TiO2 coating on the glass beads was then tested to compare the photo-oxidation efficiencies of Hg(0) with an incident light of 365 nm. The results showed that the oxidation efficiencies of Hg(0) for Ti400 and Ti500 were higher than those of Ti300 and Ti600. To enhance the photo-oxidation efficiency of Hg(0), Ti400 was selected to examine the wave lengths (λ) of 254 nm, 365 nm and visible light with various influent Hg(0) concentrations. The effects of irradiation strength and the presence of oxygen on the photo-oxidation efficiency of Hg(0) were further investigated, respectively. This study revealed that the wave length (λ) of 254 nm could promote the photo-oxidation efficiency of Hg(0) at 140 and 160 °C, while increasing the influent Hg(0) concentration and could enhance the photo-oxidation rate of Hg(0). However, the influence of 5% O2 present in the flue gas for the enhancement of Hg(0) oxidation was limited. Moreover, the intensity of the incident wave length of 365 nm and visible light were demonstrated to boost the photo-oxidation efficiency of Hg(0) effectively.
Institute of Environmental Engineering, National Sun Yat-Sen University No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan.
Huazhen
H
Shen
Institute of Environmental Engineering, National Sun Yat-Sen University No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan.
Iau-Ren
IR
Ie
Institute of Environmental Engineering, National Sun Yat-Sen University No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan. Electronic address: ycsngi@mail.nsysu.edu.tw.
Chung-Shin
CS
Yuan
Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology No. 2, Juoyue Road, Nantz District, Kaohsiung 811, Taiwan.
Chung-Hsuang
CH
Hung
Institute of Environmental Engineering, National Sun Yat-Sen University No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan.
Wei-Hsiang
WH
Chen
College of the Environmental & Ecology, Xiamen University, Xiamen, Fujian, PR China.
Jinjing
J
Luo
Institute of Environmental Engineering, National Sun Yat-Sen University No. 70, Lian-Hai Road, Kaohsiung 804, Taiwan.
Yi-Hsiu
YH
Jen
D002384:Catalysis; D004777:Environment; D005740:Gases / Q000737:chemistry; D006358:Hot Temperature; D008628:Mercury / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D011210:Power Plants; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction
D005740:Gases; C009495:titanium dioxide; D014025:Titanium; D008628:Mercury
Calcination temperature; Irradiation strength; Oxygen content; Photo-oxidation of Hg(0); Titanium dioxide