| abstract |
Disclosed is an exhaust gas purification apparatus comprising a water-absorbing system (1) and a NOx-absorbing system (2), wherein the water-absorbing system (1) comprises a Y-type zeolite, and the NOx-absorbing system (2) is arranged downstream to an exhaust gas discharged from the water-absorbing system (1), comprises a zeolite, and contains a transition metal ion in its cation exchange site. In the NOx-absorbing system (2), the NOx-absorbing ability is increased as the decrease in the water content of the exhaust gas. Therefore, when such a NOx-absorbing system is combined with a water-absorbing system comprising a Y-type zeolite (which has a high Al2O3 content and can absorb a larger amount of water compared to other types of zeolite), the NOx-absorption ability at a lower temperature can be particularly improved. |