A COMPARATIVE-STUDY OF MEAPO MOLECULAR-SIEVES WITH AFI STRUCTURE TYPE

MeAPO molecular sieves (Me: Co, Mn, and Zn) with the AFI structure typ e and an AlPO4-5 for reference were synthesized. The products were cha racterized by X-ray fluorescence, XRD, thermodielectrical analysis, NH 3 adsorption, and temperature-programmed reduction (t.p.r). It was sho wn that the cell parameters and the adsorption volume of MeAPO-5 molec ular sieves are higher than those for AlPO4-5. Thermodielectrical data are consistent with the fact that the charge of the anionic framework of the as-synthesized MeAPO-5 is compensated by (HTEA)+. T.p.r. resul ts show that Co, Zn, and Mn are included in the molecular sieve framew ork of CoAPO-5, ZnAPO-5, and MnAPO-5.