Research of copper contained SAPO-34 zeolite for NH3-SCR DeNOx by solvent-free synthesis with Cu-TEPA

Abstract

With the introduction of solvent-free method, copper-contained SAPO-34 zeolite was synthesized by mixing, grinding and heating the raw materials with Cu-TEPA added in the precursor. Compared to conventional method of hydrothermal synthesis along with ion-exchange, the direct synthesis with the absence of solvent has effectively reduced the waste production, increased the yield and accelerated the crystallization period as well. The so-prepared sample exhibited absolute symmetry of isolated Cu2+ by incorporating into the cativy of SAPO-34. The ion-exchange process produced some bulk CuO on zeolite surface, and it might affect the crystallinity of zeolite. The addition of copper led to changes in surface area, pore structure, redox performance and acid sites for SAPO-34. The exchanged sample show wide active temperature and excellent low temperature NOx conversion, but the activity and selectivity decreased significantly at a high temperature. The direct synthesized sample exhibited remarkable NOx conversion rate and high N2 selectivity with a more efficient preparation, it also retained the excellent hydrothermal stability of chabazite structure.