Selective Catalytic Reduction (SCR) - Hot Topic IZC18

Another hot topic at the International Zeolite Conference (IZC18) was centered around the uses of zeolites for environmental applications, specifically selective catalytic reduction (SCR).  For those of you who were unable to attend or may have missed these sessions, we have selected a few talks related to this topic, summarized them and by clicking on the titles you can download the associated abstracts:

  • Next will be Oral Presentation 150: ZTS-1 Novel intergrowth of AFX/CHA structure (Tosoh Corp, Japan)
    • goal is to find a new catalyst or adsorbant by making intergrowths of 2 different 8 membered ring zeotypes (AFX and CHA)
    • intergrowth of SSZ-16 (AFX) and SSZ-13 (CHA) phases was produced by mixing the SDAs for each structure (butamethonium bis(DABCO) dibromide and TMA Adamantyl hydroxide)
    • the ratios of each SDA in the gel controls the ratio of AFX/CHA in the product, and the CHA phase does not appear until all the AFX has crystallized
    • XRD patterns showed the the product (which Tosoh refers to as ZTS-1) is a true intergrowth and does not contain separate crystalline phases
  • Lastly is the Session: Stabilized Zeotype Cu-SAPO-34 for NH3 SCR of NOx s by Subramanian Prasad (BASF Corp – USA)
    • Cu-SAPO-34 shows better reactivity and control of NOx than Cu-SSZ-13 at low temps (<200 C) by it has a short lifetime due to a high sensitivity to water vapor under SCR conditions
    • Si NMR suggests that Si islands form during post calcination ion exchange with NH4 NO3, due to hydrolysis of Si-Al bonds in the aqueous environment
    • Hydrolysis of the Si-Al bonds was avoided by converting the H+ form of calcined SAPO-34 to the ammonium form by exposing it to anhydrous NH3 gas (instead of an aqueous solution)
    • Si NMR confirmed the Si-Al bonds remained intact with this new approach and SCR tests showed the new catalyst to be more active and stable than Cu-SAPO-34 produced by the conventional method

SACHEM produces structure directing agents for zeolite synthesis.  ZeoGen™ is a portfolio of SDA designed to meet the stringent regulations of the zeolite industry.