氮氧化物排放是造成大气污染的重要原因，我国众多行业工况不同的烟气排放都面临着严格的脱硝要求。对于气相还原法难以适用的工业烟气，氧化-吸收法是控制氮氧化物排放的重要手段，但其所存在的共性问题是：适度氧化产物NO2的吸收效率不高，并伴有NO再释放，导致脱硝效率降低；氮氧化物的吸收过程中缺乏必要调控，导致脱硝产物最终仍以硝酸盐形式存在，易造成二次污染等问题。为此本研究充分利用烟气脱硫所产生的亚硫酸根S(IV)，通过探索适当的调控添加剂，运用适宜的氧化还原电位进行调节，构建优化的吸收-还原体系，实现氮氧化物的高效吸收，并对脱硝中间产物进行同步形态调控。通过研究探索出经济有效的阻氧/还原剂配伍，提高S(IV)的脱硝利用率。揭示液相相关还原作用机制，在有效抑制NO再释放的同时，实现脱硝产物高效无害化还原。通过研究阐明相关动力学问题及化学作用机制，为解决湿法脱硝技术的关键问题及其应用提供理论依据。

Nitrogen oxides emission is one of the major reasons to cause air pollution. Many industries will face the challenge of stricter regulations on flue gas denitrification. For flue gas that is not suitable to be treated with reduction method (SCR or SNCR), oxidation-absorption method has illustrated its potential. However, oxidation-absorption method still has its drawbacks including: (1) Removal efficiency of NOx needs to be increased. Absorption of NO2 would produce new-generated NO which could decrease removal efficiency of flue gas denitrification. (2) Lack of control on N forms that may cause secondary pollution (nitrate discharge). Herein, a novel absorption-reduction process is built to achieve high efficiency removal of NOx from flue gas. Based on the principle of “waste controlled by waste”, desulfurization by-product sulfite (S(IV)) would be utilized as absorbent. Additives would be screened and parameters including ORP and pH value of the solution would be adjusted in order to promote the transformation of NOx into NO2- against NO3-. Compatibility of additives and their effect on inhibition of sulfite oxidation would also be investigated to improve the availability of absorbent for denitrification. Moreover, reduction mechanism of nitrite would be studied to guide the achievement of two goals: (1) inhibit the re-emission of NO. (2) transform NOx absorption product into harmless N2. Reaction mechanism and relevant kinetic equations during NOx absorption and nitrite reduction would be inferred to provide theoretical guidance for flue gas denitrification by absorption method.