Preparation Of Mn-Cu Adsorbent With Semi-coke And The Combined Removal Of SO₂ And NO From Flue Gas

In recent years,the government has intensified the treatment of environmental pollution,and the emission of coal-fired flue gas needs to adapt to ultra-low pollutant emission standards.So,it is imperative to develop efficient and cheap flue gas pollutant removal technology.In this paper,the metal components of Mn and Cu were successfully loaded on the semi-coke support by ultrasound-assisted high-pressure impregnation method.A series of Mn-Cu adsorbents were obtained with different impregnation molar ratio,and their removal experiments of SO₂ and NO were carried out on the fixed-bed system.XRD,XPS,SEM,BET and FTIR were also used to characterize fresh and used adsorbents,which is helpful to reveal the desulfurization and denitrification mechanism.The main conclusions are as follows:The experimental results show that the bimetal Mn-Cu adsorbent has better NO removal performance than that of the single metal Mn or Cu adsorbent.The best denitration adsorbent is the M3C1,and the breakthrough time and capacity are 300 min and 10.07 mg/g,respectively.AAS tests show that the actual load ratio of Mn and Cu in M3C1 is 1:1,and each mass is about10 mg.Similarly,the SO₂ removal ability of bimetal Mn-Cu adsorbent is much higher than that of the single metal adsorbent.The optiaml desulfurization adsorbent is M4C05 with the breakthrough time of 184 minutes and the capacity of 14.62 mg/g.The effect of temperature on the removal ability of Mn-Cu adsorbent depends on the relative content of Mn and Cu.When Mn content of the adsorbent is more,the increasing temperature is beneficial to remove NO and SO₂.But,when the components of Cu content is more,the removal ability of NO and SO₂ will weak with rising temperature.CO₂ has little effect on the removal of SO₂,and it has a certain inhibitory effect on NO removal.O₂ plays a crucial role in the removal of SO₂ and NO.The increase of SO₂ and NO initial concentration will decrease the removal efficiency.XRD and XPS results shows that metal components exist in the forms of Cu,Cu₂O,MnO₂,and Mn₃O₄ in the Mn-Cu adsorbents.The removing SO₂process is divided into two stages of 100%removal zone and gradually weaken zone.SO₂ removal mainly depends on 100%removal zone.The active components of adsorbent include Mn⁴⁺and Mn³⁺.SO₂ is oxidized by O₂ and Mn⁴⁺(Mn³⁺)to sulfates,which retains in adsorbent surface to cause the failure of active components Mn and Cu.The removal of NO is divided into three stages:initial reaction zone,slow weaken zone and rapid weaken zone.The removal of NO mainly depends on the slow weaken zone.The active components are Cu⁰ and Mn³⁺.The valence of Mn³⁺decreases and the oxidative properties are exhibited.While Cu⁰ shows some catalytic properties.NO is converted to N₂（O）.