Gas-phase elemental mercury removal in a simulated combustion flue gas using TiO2 with fluorescent light

• Published in: Journal of the Air & Waste Management Association (1995) 2012-10, Vol.62 (10), p.1208-1213
• Main Authors: Cho, Jae Han, Lee, Tai Gyu, Eom, Yujin
• Format: Article
• Language: English
• Subjects: Air Pollutants - chemistry; Air Pollution - prevention & control; Applied sciences; Atmospheric pollution; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Environmental Restoration and Remediation - methods; Exact sciences and technology; Gases - analysis; Gases - chemistry; General and physical chemistry; General processes of purification and dust removal; Mercury - analysis; Mercury - chemistry; Photolysis; Pollution; Prevention and purification methods; Reactors; Republic of Korea; Spectrophotometry, Atomic; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titanium - chemistry
• ISSN: 1096-2247; 2162-2906
• DOI: 10.1080/10962247.2012.700901

A previously proposed technology incorporating TiO 2 into common household fluorescent lighting was further tested for its Hg 0 removal capability in a simulated flue-gas system. The flue gas is simulated by the addition of O 2 , SO 2 , HCl, NO, H 2 O, and Hg 0 , which are frequently found in combustion facilities such as waste incinerators and coal-fired power plants. In the O 2 + N 2 + Hg 0 environment, a Hg 0 removal efficiency (η Hg ) greater than 95% was achieved. Despite the tendency for η Hg to decrease with increasing SO 2 and HCl, no significant drop was observed at the tested level (SO 2 : 5-300 ppm v , HCl: 30-120 ppm v ). In terms of NO and moisture, a significant negative effect on η Hg was observed for both factors. NO eliminated the OH radical on the TiO 2 surface, whereas water vapor caused either the occupation of active sites available to Hg 0 or the reduction of Hg 0 by free electron. However, the negative effect of NO was minimized (η Hg > 90%) by increasing the residence time in the photochemical reactor. The moisture effect can be avoided by installing a water trap before the flue gas enters the Hg 0 removal system.