Experimental Study On SO₂ Autocatalytic Desulfurization And Denitrification By Peroxymonosulfat

Coal combustion is a major source of sulfur dioxide（SO₂）and nitric oxide（NO）in the atmosphere and poses serious harms to both the environment and human health.At present,wet desulfurization and selective catalytic reduction denitration are mostly used in industry.This kind of step-by-step and series removal of pollutants has the problems of high investment,high operation cost and large floor area.Therefore,the development of efficient and green flue gas simultaneous desulfurization and denitration technology has become a research hotspot.In this paper,green and efficient potassium peroxymonosulfate（PMS）is used as the oxidant,and nitrogen（N₂）,SO₂ and NO are used as simulated flue gas.The effects of different reaction conditions,such as SO₂:NO concentration ratio,reaction solution temperature and PMS concentration,on the simultaneous desulfurization and denitrification of PMS were analyzed.In order to further improve the denitration efficiency,a superhydrophobic guide rope was used to enhance the directional transport of NO in the solution and improve the oxidation efficiency.The results show that SO₂ has a promoting effect on the removal of NO.When the concentration of SO₂increases from 350 ppm to 1700 ppm,the removal efficiency of NO increases by 35%;increasing the temperature and increasing the concentration of PMS can make PMS produce more active substances and improve desulfurization and denitrification efficiency,but too high temperature and PMS concentration are not conducive to the reaction of gas and active substances.The other components CO₂ in the flue gas had no effect on desulfurization and denitrification,while O₂ promoted the removal of NO.When the content of O₂ increased from 0%to 15%,the removal efficiency of NO was increased by 14.6%.The analysis of the quenching experiment of the PMS oxidation system shows that there are hydroxyl radicals（·OH）,sulfate radicals(SO₄^·-)and singlet oxygen（¹O₂）in the PMS solution,and·OH is the main active substance for removing SO₂.;¹O₂dominates the removal of NO.The higher the O₂ concentration,the more favorable it is for the generation of NO₂^-,which increases the efficiency of NO removal.In the PMS reaction system,there are NO₂^-,NO₃^-,SO₃^2-and SO₄^2-ions in the solution,the concentrations of SO₄^2-and SO₃^2-in the solution are mainly affected by the concentration of SO₂,and the removal efficiency of NO has a great influence on the concentration of NO₃^-;SO₂ And the final products of NO oxidation are SO₄^2-and NO₃^-.The high concentration of O₂ is beneficial to the formation of NO₂^-and increases the NO removal efficiency.In the PMS reaction system,there are NO₂^-,NO₃^-,SO₃^2-and SO₄^2-ions in the solution,the concentrations of SO₄^2-and SO₃^2-in the solution are mainly affected by the concentration of SO₂,and the removal efficiency of NO has a great influence on the concentration of NO₃^-;SO₂ And the final products of NO oxidation are SO₄^2-and NO₃^-.SO₂ dissolves in water to generate SO₃^2-and HSO₃^-which can react with SO₄^·-and·OH to form SO₃^·-.SO₃^·-can quickly generate SO₅^·-under the promotion of O₂,SO₅^·-can generate SO₄^·-through self-decomposition,forming a free radical cycle;NO₂ generated by NO oxidation can also react with SO₃^2-and HSO₃^-in solution to generate SO₃^·-and HSO₃^·-radicals,which participate in the autocatalytic cycle of SO₂.SO₂ can promote the removal of NO,which means that there is a synergistic effect between SO₂ and NO gas.The difficulty of NO being soluble in water is the current problem of wet denitrification.A guide rope made of superhydrophobic material is added to the reactor.The superhydrophobic guide rope has aerophilicity and can fix and directionally transmit bubbles under water.Compared with the original PMS solution,the NO removal efficiency increased by 13%under the optimal experimental conditions.The addition of superhydrophobic guide rope to the PMS reaction system not only significantly improved the NO removal effect,but also had a significant impact on the simultaneous desulfurization and denitrification.Under the same reaction conditions,the removal efficiency of SO₂ was 100%,and the removal efficiency of NO was 7%higher than that of the original PMS reaction system,and22.6%higher than that of single denitrification.The addition of superhydrophobic guide rope improves the removal efficiency of PMS advanced oxidation for the simultaneous removal of SO₂ and NO.PMS liquid-phase advanced oxidation process is a green,safe and promising gas pollutant control method.