Absorption of NO from simulated flue gas using citric acid complexed ferrous ion/heat coactivated persulfate system

Persulfate liquid-phase advanced oxidation technology (AOP) has become a feasible and effective choice in wet flue gas desulfurization (WFGD) technology due to its efficient oxidation capacity and environmentally friendly characteristics. This paper proposes a new process for removing NO from simulated flue gas using FeⅡCA/heat co-activated persulfate system. The main influencing factors, active components, reaction products and reaction process of NO purification system were mainly studied. The results show that in the process of purifying NO in the system, active substances such as S2O82-, •OH and •SO4- will be produced, among which •OH is the main free radical that oxidizes NO. The liquid phase products after the system absorbs and oxidizes NO are mainly NO3- and SO42-, and the material balance before and after the reaction is satisfied. In the process of purifying NO, by increasing the concentration of persulfate and selecting an appropriate Fe2+/CA ratio, the NO purification effect of the system can be promoted. In addition, the purification effect is closely related to temperature. However, if the pH value of the solution is increased or the NO concentration is too high, the NO purification effect of the system will be reduced. For this reason, under suitable process conditions, the NO purification rate of the system can reach 71.1%. The experimental results confirmed the feasibility of FeⅡCA/heat co-activated persulfate to remove NO from flue gas, and provided a theoretical basis for further research and practical application of this system.