Contributed by Lovat V. C. Rees

Verified by Yingcai Long, by P. Sidheswaran, and by G. Price

Type Material (NaAlO₂)₇(SiO₂)₉

Method L V. C. Rees and S. Chandrasekhar [1]

Batch Composition Al₂O₃ : 2.2 SiO₂ : 5.28 NaF:105.6 H₂O

Source Materials

distilled water
sodium fluoride (BDH Analor)
kaolinite (Al₂O₃ : 2.2 SiO₂ : 2 H₂O) ^a

Batch Preparation (for 10 g dry product)

(1) [87.7 g water + 10.4 g sodium fluoride], stir and make a slurry
(2) [(1) + 12.7 g kaolin], mix thoroughly

Crystallization

Vessel: sealed polypropylene
Time: 60 days
Temperature: 85⁰C
Agitation: none
pH: initial 7.5, final 9-10

Product Recovery

(1) Filter and wash thoroughly with distilled water
(2) Exchange twice with NaCl solution
(3) Wash with distilled water (adjusted to pH = 10 with NaOH)
(4) Dry at 85⁰C for 24 hours
(5) Rehydrate over water vapor from saturated NaCl solution

Product Characterization

XRD: Strong zeolite P competing phases: CHA, no SOD
Elemental Analysis: NaAlO₂. 1.18 SiO₂ (by atomic absorption spectroscopy) ^b,c
Crystal Size and Habit: spherulitic particles of approximately 10 um dia.
Click here to view XRD pattern

Reference

[1] L. V. C. Rees, S. Chandrasekhar, Zeolites 13 (1993) 535

Notes

a. Kaolinite from Trivandrum, Kerela, India

b. Dissolution of the zeolite sample for atomic adsorption: 0.1 g sample was treated with 30 mL of a mixture of HCl (37%), HF (48%) and distilled water (ratio 1:1:1); the same was kept for two to three days for complete dissolution.

c. ²⁹Si MAS NMR gave five lines with chemical shifts of -86.79, -91.55, -97.19, -102.86 and -107.10 ppm. ²⁷Al MAS NMR gave two lines, intense Al (tet) at 58.58 and weak (oct) at -0.42 ppm.