Catalytic combustion of isopropanol over Co-Mn mixed oxides modified ZSM-5 zeolite membrane catalysts coated on stainless steel fibers

Abstract

Abstract A novel gradient porous Co-Mn mixed oxides modified ZSM-5 zeolite membrane/PSSF (paper-like stainless steel fibers) catalyst was prepared for catalytic combustion of isopropanol in a membrane reactor. First, the paper-like sintered stainless steel fibers (PSSF) support was fabricated by wet lay-up papermaking method and sintering process. Then, ZSM-5 zeolite membranes were synthesized on the surface of stainless steel fibers by using secondary growth process. Finally, the cobalt and manganese mixed oxides modified ZSM-5 zeolite membrane catalysts were prepared by wet impregnation method. These novel modified membrane catalysts were characterized by using SEM, XRD, N2 adsorption–desorption isotherms and XPS, respectively. The catalytic activity test was carried out over a membrane reactor filled with ZSM-5 zeolite membrane catalysts and granular catalysts, respectively. The experimental results showed that the junctures of stainless steel fibers were completely sintered together to form a three-dimensional network structure and ZSM-5 zeolite membrane was fabricated on the PSSF support with the thickness of 1.78 μm. The cobalt element existed as Co3+and Co2+, maganese element existed as Mn4+ and Mn3+. The results of catalytic activity tests showed that catalytic activity for isopropanol over ZSM-5 zeolite membrane catalyst was superior to that over granular ZMS-5 catalyst, the reaction temperature of 50% and 90% conversion of isopropanol over ZSM-5 zeolite membrane catalyst dramatically decreased. The Co-Mn(1:4)/ZSM-5/PSSF catalysts presented the most excellent catalytic activity for isopropanol combustion, compared with Co/ZSM-5/PSSF and Mn/ZSM-5/PSSF catalysts, respectively.