A critical review on the method of simultaneous removal of multi-air-pollutant in flue gas

Simultaneous removal of multi-air-pollutant (sulfur dioxide (SO2), nitric oxide (NO) and elemental mercury (Hg-0) etc.) in flue gas, is a hot topic in the field of air pollution control due to its superiorities of highly integration, relative low-cost and easy operation. This paper comprehensively reviews the recent development of the technology for simultaneous removal of SO2, NO and Hg-0 in flue gas, which includes (1) gas-solid phase method, (2) liquid phase oxidation, (3) gas phase oxidation and (4) combined phase oxidation method. The paper focuses on the technical mechanisms, the effects of key influencing factors, and the merits and demerits of these methods. Using SCR method of gas-solid phase to remove Hg-0 and NO simultaneously has been widely studied, due to the extensive application of SCR equipment in coal-fired power plants. The radical-induced oxidation (including advanced oxidation process (AOP) and gas phase oxidation) method received considerable attention because it could deeply and cooperatively remove SO2, NO and Hg-0. The suggestions and prospects for future researches were proposed finally. This review may give some inspirations in developing novel technologies for multi-air-pollutant removal from flue gas.