Zeolite science

S. Chandra MohanZEOLITE SCIENCEIntroductionMicroporous (aperture diameter less than 2 nm),Mesoporous (aperture diameter of 250 nm),Macroporous (aperture diameters larger than 50 nm) materials,

Microporous to mesoporous to macroporous

From Natural Zeolites to Synthesized ZeolitesFrom Low-silica to High-silica ZeolitesFrom Zeolites to Aluminophosphate Molecular Sieves and OtherMicroporous Phosphates12-Membered-ring Micropores to Extra-large MicroporesExtra-large Micropores to MesoporesEmergence of Macroporous Materials

Microporous MaterialsMicroporous materials with regular pore architectures comprise wonderfully complex structures and compositions.Zeolites - microporous materials.crystalline aluminosilicate or silica polymorph based on corner-sharing TO4, T-atoms (Si, Al, P, Ga, Ge, B, Be, etc.)Zeolites have the ability toact as catalysts for chemical reactions which take place within the internal cavities

Structural Building Units of ZeolitesPrimary Building Units

T= Si,Al,P,B, Ga, Be, etc

Secondary Building Units (SBUs)18 SBU 16 T

D4r

Cage-building Units

n-rings

Characteristic Chain- and Layer-building Units

Periodic Building Units (PBUs)

Composition of ZeolitesLowensteins ruleAl(4 Si)Si(0Al, 4Si) , Si(1Al, 3Si), Si(2Al, 2Si), Si(3Al, 1Si), Si(4Al, 0Si)Si/Al ratio -1 to Si neutral no cationsSi4+ and Al3+ balanced by cations, Na, Li, K etc

Small-pore - LTA, SOD, and GIS 8 - 4 A . Medium pore MFI 10-ring - 5.5A .Large pore FAU, MOR, and *BEA -12 - 7.5 A .

Linde Type A ( LTA )| Na 12 (H 2 O) 27 | 8 [Al 12 Si 12 O 48 ] 8Three - dimensional eight - ringlinking sodalite cages through double four - rings

Faujasite ( FAU )| (Ca,Mg,Na) 29 (H2O) 240 | [Al 58 Si 134 O 384 ]Three - dimensional 12 - ringlinking sodalite cages through double six - rings supercage

| Nan (H 2 O) 16 | 8 [Al n Si 96-n O 192 ]

comprising pentasil chains

ZSM 5Mesoporous 2-50nmMCM-41 (MCM stands for Mobil composite of matter) MCM-48 and SBA-15 (SBA stands for University of California, Santa Barbara)Based on the diffraction characteristics, porous materials may be divided into three types: amorphous, sub-crystal, and crystal. amorphous solid does not give any diffraction peakssub-crystal gives no diffraction peaks or very few broad diffraction peakscrystalline solid can produce a set of characteristic diffraction peaks which correspond to its crystallographic system and symmetry. macroporous materials,ceramics and cement - irregular pores and wide pore-size distribution.MCM 41MCM 48 SBA 15

propertieswell defined pore sizes and shape, narrow pore-size distribution;highly ordered pore (or channel) structure system at the nanometer level;adjustable pore size in the range of 1:3 to 30 nm;various structures, wall compositions, and pore shapes;high thermal and hydrothermal stability if properly prepared or treated;high surface area, large pore volume various controllable regular morphologies at different scale from nanometers to micrometers;

control the mesostructures change various reactant concentrations, reaction temperature, and reaction-mixture composition;adjust the surfactant effective-packing parameter, g by using different structured surfactants, adding additives, or changing synthesis conditions.

MCM- 41adjustable in the range of 1.510 nm and 4.0 nmhexagonal or cylindrical?

Porous HostGuest assembley zeolites with encapsulated metal clusters or metal ion clusters, and occasionally in the clusters there are nonmetal ligands such as carbonyl groups. Zeolites with dye moleculesPolymers or carbons such as fullerenes and carbon nanotubes in zeolitic materialsInorganic semiconductor particles in zeolitesMetal -complex-encapsulating zeolites. Thank you