Synthesis and characterization of NOx adsorbents

The aim of this study is to develop the Ba-based, MCM41 supported adsorbent that has a high adsorption capacity for removing the NO2 emission which is one of the NOx gases. MCM-41 is a member of mesoporous M41S family, noticed with having high surface areas and narrow pore-size distributions. Due to superior properties, MCM-41 become a candidate as a support material. By using different preparation methods metals incorporated MCM-41 adsorbent/catalysts can be synthesized. It?s known that having a molecular sieve property, nano structural materials have an important application in selective reactions. So that, absorption capacity of Ba-based adsorbents can be improved by using MCM-41 as a support material.In this study, Ba-based MCM-41 supported adsorbents were prepared by using both direct hidrothermal synthesis method and wet imregnation method. XRD, nitrogen asdorption-desorption analysis (BET-BJH), TGA-DSC, FTIR and SEM-EDS analysis were used for determining the structural and physical properties of synthesized materials. As a result of characterization test, XRD patterns show that cystal structure of MCM-41 was achieved and high surface areas (1150-1278 m2/g) were obtained. With an increasing amount of Ba incorporation, surface areas of adsorbents decreases. XRD analysis shows that in Ba-based adsorbents, there are barium oxide and barium species, besides silicate formation.In impregnation method in order to increase the surface area of the Ba-based adsorbents, citric acid was added to the imregnation solution in different amounts. Characterization analysis shows that adsorbents that were prepared by addition of citric acid have higher surface areas and more homogeneous pore size distrubution were obtained. And also with addition the citric acid higher pore volume was achieved, so that the barium clusters that are seen in the imregnation method were hindered.