Article,
Estimation and comparison of pore charge on titania and zirconia membranes prepared by sol-gel route using zeta potential measurement
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, 28 (3): 327-333 (November 2003)
Abstract
An attempt has been made to synthesize ceramic titania and zirconia
membranes by sol-gel process by filtering respective viscous colloidal
sol through microporous alumina support and gelling followed by sintering
at 400degreesC and 470degreesC respectively. The static charge on
the pores of the so formed membranes and the pore size distribution
determine the applicability in filtering colloidal solution. The
mean pore size from SEM were found to be 0.65 mum and 0.54 mum for
titania and zirconia membranes respectively with 1.47 x 10(7)/cm(2)
as pore density for both. The filtration characteristics during membrane
layer formation showed that the membrane layer formation started
after 35 minutes in the case of titania membrane and 40 minutes in
the case of zirconia membrane. From the gravimetric estimation of
water content of the membranes the thickness of the membrane was
found out to be 3 mum and the porosity was found out to be 0.30 for
both the cases. The particle charge density was estimated from the
zeta potential and the particle size. The pore charge density was
estimated from the particle charge density, pore density, pore diameter
and the thickness of the membrane layer. The membrane pore charge
density was found to vary between 3 to -1 mu Coulombs/cm(2) in the
case of titania membrane and 7 to - 0.5 mu Coulombs/cm(2) in the
case of zirconia membrane in the pH range 1-12.
