在中孔材料上催化还原及可逆吸附氮氧化物

NOx can contribute significantly to acid precipitation or urban photochemical smog. Both selective catalytic reduction (SCR) of NOx with hydrocarbons and adsorption of NOx in the presence of oxygen were investigatated for the abatement of NOx emissions from stationary or mobile sources.Firstly, a series of mesoporous aluminosilicate materials were synthesized and tested for nitric oxide (NO) reduction by propene in the presence of oxygen on their Cu ion-exchanged forms. The experimental results revealed that NO reduction activity was not decreased but slightly increased above 400℃ on Cu-Al-MCM-41 in the presence of water vapor as compared to that on Cu-ZSM-5, which indicated Cu-Al-MCM-41 was more water resistant than Cu-ZSM-5. In addition, NO reduction activity was also investigated on the Ni, Co or Mn ions doped Cu-Al-MCM-41 samples in the absence or the presence of water vapor. It was found that NO conversion on Ni doped Cu-Al-MCM-41 was increased below 350 oC in the absence of water vapor, and NO conversion was also enhanced above 400 oC upon introducing water vapor into the feed gas.Secondly, TiO2, ZrO2 and their mixtures were prepared by templating method, sol-gel techniques and microemulsion method. Specially, Ce or Mn doped ZrO2 prepared in reverse microemulsions or conventional precipitation were tested for NOx adsorption experiments. The prominent results show that the amount of NOx adsorbed was increased with increasing MnO2 content in the different MnO2/ZrO2 samples. The maximum uptake value of 18 mg NOx /g sorbent was available on the 15% Mn-Zr sample at 200 oC, while the value of 32.5 mg NOx /g sorbent was obtained on the 5% Mn-Zr sample at 100 oC. TPD results shows that the temperature for the desorption of NOx was decreased with addition of CO and C3H6 into the argon desorption streams.

氮氧化物可导致酸雨和城市光化学烟雾，已成为我国大城市的主要大气污染物。本研究拟采用柱撑脱土等中孔材料，开展对氮氧化物净化的催化还原和可逆吸附的实验研究。并考察二氧化硫和水对催化剂的中毒机理及吸附剂的吸附特性的影响。此研究可为严格控制氮氧化物从固定源和流动源的排放提供技术依据，具有很强的研究价值和应用背景。