The crystallization of zeolite NaA in the presence of various surfacta
nts (sodium dodecyl sulfate, Aerosol OT, cetyltrimethylammonium bromid
e, Nonidet P40) and of poly(ethylene glycol) was studied and compared
to a control crystallization with no additive present. Crystalline-gro
wth curves were determined by quantitative X-ray diffraction studies o
f samples removed periodically from the hydrothermal system. Crystal-s
ize distributions and linear crystal-growth rates were determined by s
canning electron microscopy, and from these data, nucleation profiles
were constructed. Changes in the concentrations of soluble aluminum an
d silicon in the aqueous phase of the hydrothermal system during cryst
allization were monitored by inductively coupled plasma atomic emissio
n spectroscopy. The additives were shown to lengthen the prenucleation
period, shorten the nucleation period, and increase the linear rate o
f crystal growth. All but Aerosol OT increased the total number of nuc
lei produced and gave crystals with a reduced mean size and narrower s
ize distribution. These effects may be attributed to an effective redu
ction in the water content of the hydrothermal system. Aerosol OT redu
ced the number of nuclei produced and gave larger crystals, an effect
that may be attributed to a specific interaction with aluminum species
. In general, the aluminum concentration in the aqueous phase was foun
d to decrease dramatically during the period of crystal growth.