A pilot-scale TiO2 photocatalytic system for removing gas-phase elemental mercury at Hg-emitting facilities

Cho, Jae Han; Eom, Yujin; Jeon, Seun; Lee, Tai Gyu

doi:10.1016/j.jiec.2012.07.016

Cited by 30 publications

(5 citation statements)

References 24 publications

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“…The ultraviolet (UV)-induced oxidation, also known as photocatalytic oxidation (PCO), with unique advantages of low-energy consumption and high efficiency, as well as simple and pollution-free operation, has proved to be a practical advanced oxidation technique for disposal of the pollutants. , Moreover, it is more attractive than other systems in that it can efficiently eliminate various environmental contaminants under mild conditions. , With regard to removal of SO 2 from flue gas, many studies have focused on SO 2 removal through UV/TiO 2 , UV/H 2 O 2 , or UV/DBD-O 3 systems. − However, considering the massive consumption of H 2 O 2 and the cost of O 3 formation, the UV/TiO 2 method is the most promising method for the removal of SO 2 from coal-fired power plants. Furthermore, the TiO 2 -based photocatalytic technique has great potential to remove simultaneously SO 2 , NO, and elemental mercury, − which are common gaseous pollutants in coal combustion flue gas. In our previous studies, , copper-based and cerium-based TiO 2 nanofibers showed excellent mercury removal activity under UV irradiation.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

2017

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Efficient and economical technologies are essential to the control of SO 2 , the emission of which poses serious health concerns and environmental risks. Photocatalysis is an attractive method for reducing SO 2 emissions. To reduce energy consumption for excess moisture evaporation, a dry photocatalytic oxidation (DPCO) system was used instead of a traditional gas−liquid process in this study. Considering that TiO 2 is a widely applied photocatalyst for the purification of gaseous pollutants, this study investigated the photocatalytic removal of SO 2 over different TiO 2 -based nanofibers. Results show that the reduction of SO 2 was mainly due to oxidation. Under ultraviolet irradiation, the removal of SO 2 was enhanced by the presence of NO 2 , which was formed by the oxidation of NO. More interestingly, the SO 2 removal efficiency remains 100% over cerium-based titania nanofibers with an increase in gas humidity, indicating that this sample has excellent resistance to H 2 O. This is very beneficial for application in an actual flue gas atmosphere, where H 2 O is inevitable. In contrast, H 2 O played a bifacial effect in the photocatalytic removal of SO 2 over copper-based titania nanofibers. Under low levels of H 2 O (<4%), competitive adsorption for active sites leads to the deactivation of photocatalytic activity, while addition of 8% H 2 O resulted in more SO 2 dissolution. Nevertheless, the promoting effect was limited; competitive adsorption was the major factor. Accordingly, the main reaction products are H 2 SO 4 and H 2 SO 3 . These indicate that combining photocatalysis technology with TiO 2 -based nanofibers is a promising strategy for oxidizing SO 2 during a DPCO process.

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Section: Introductionmentioning

confidence: 99%

Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

2017

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“…Main application includes exterior building materials, since 1990s several industries have installed photocatalytic filters with UV lamps inside air purifiers; applications in deodorization are implemented in hospitals and officers. Last year, both exterior and road materials have been increased [76][77][78][79][80][81]. [58] Methylene blue 27.9 30 Table 3.…”

Section: Photocatalytic Efficiency and Perspectivesmentioning

confidence: 99%

Phthalocyanines: Alternative Sensitizers of TiO2 to be Used in Photocatalysis

Vallejo¹,

Díaz‐Uribe²,

Quiñones³

et al. 2017

Phthalocyanines and Some Current Applications

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Currently, titanium dioxide is a most researched semiconductor in photocatalysis field; however, practical applications of TiO 2 are limited due to high band gap (3.2 eV). In last decades, researchers implemented several strategies to improve photoactivity of TiO 2 in visible electromagnetic spectrum. Titanium dioxide (TiO 2) sensitization for absorption of naturals and/or synthetics organic dyes is an important research subject in the field, and it is an efficient method to develop practical application in waste treatment. In this chapter, we review main theoretical aspects of sensitization process of TiO 2 by phthalocyanines and its effect in photocatalytic properties. In the last section, we review reports of photocatalytic systems.

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“…In contrast, Chen deduced that NO drastically reduced E cap of mercury under various light irradiations. A pilot-scale photocatalytic Hg 0 emission control system was installed at a real combustion facility, and results showed that lower η Hg was due to the various acid gases present . As a consequence, a systematic study of the effects of those components, including NO, on Hg 0 photocatalytic removal is essential.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Evaluation of Mercury Photocatalytic Oxidation by Cerium-Based TiO₂ Nanofibers

Wang

Zhao

Zhang

2017

Ind. Eng. Chem. Res.

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Efficient and economical technologies are essential to the control of mercury, the emission of which imposes serious health concerns and environmental risks. Photocatalysis is an attractive method for reducing mercury emissions. Considering that titania is widely applied in the photodegradation of toxic contaminants, this study investigated the removal of mercury over cerium-based titania nanofibers (CBTs) at low temperature. According to the results, in the atmosphere containing SO2, both catalyst and UV proposed adverse effect on Hg0 oxidation. The competition between SO2 and Hg0 for active sites and the formation of cerium sulfate are responsible for the deactivation of Hg0 removal capacity. More interestingly, without O2, NO and HCl still exerted a superior promoting effect on mercury removal. Entirely different from the properties under SO2, UV and catalyst both facilitated Hg0 oxidation with the existence of HCl. Meanwhile, effects of the copresence of NO and SO2 on Hg0 removal were further investigated. NO was the most dominant gas component enhancing the removal capacity. Considerable high removal efficiency (>80%) was observed in the presence of 300 ppm of NO and 400 ppm of SO2. These indicate that combining photocatalysis technology with CBTs is a promising strategy to oxidize mercury under low-rank coal combustion flue gas in which the concentration of HCl is relatively low.

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A pilot-scale TiO2 photocatalytic system for removing gas-phase elemental mercury at Hg-emitting facilities

Cited by 30 publications

References 24 publications

Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Phthalocyanines: Alternative Sensitizers of TiO2 to be Used in Photocatalysis

Comprehensive Evaluation of Mercury Photocatalytic Oxidation by Cerium-Based TiO₂ Nanofibers

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A pilot-scale TiO2 photocatalytic system for removing gas-phase elemental mercury at Hg-emitting facilities

Cited by 30 publications

References 24 publications

Photochemical Removal of SO2 over TiO2-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Photochemical Removal of SO2 over TiO2-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Phthalocyanines: Alternative Sensitizers of TiO2 to be Used in Photocatalysis

Comprehensive Evaluation of Mercury Photocatalytic Oxidation by Cerium-Based TiO2 Nanofibers

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Product

Resources

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Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Photochemical Removal of SO₂ over TiO₂-Based Nanofibers by a Dry Photocatalytic Oxidation Process

Comprehensive Evaluation of Mercury Photocatalytic Oxidation by Cerium-Based TiO₂ Nanofibers