TAVARES, I. F.; TAVARES, Izolda Freitas.
Resumen:
The pervaporation became an atractive separation process in the last years, mainly after
the discovery of new membranes. However, to project and improve pervaporation system is
important to develop membranes with a good thermaland chemical estability and high selectivities
and permeabilities. In this work it was used two types of ceramic membranes: alumina and zirconia
membranes. These membranes was submited to a modification process with the aim to became
dense and permeable. It was used two polymers: polydimethylsiloxane and polymethylmetacrilate.
It was used infra-red spectroscopy to confirm the presence of the siloxane on the surface of the
membrane. After the modification of the membranes it was a pervaporation system to measure the
selectivity and flux of the membranes by using mixtures of ethanol-water and isopropanol-water as
a feed solution. It was observed after alumina membranes modifications with PDMS and zirconia
membrane modification with PDMS and PMMA both membranes presents hydrophilic
characteristics, i.e., with water afinity. All membranes showed an increasing in the flux with the
increasing of water content in the feed solution. To alumina membrane modified by PDMS and
using ethanol with 95%, 48% and 23% in concentration, it was observed flux of 3.3, 5.6 and 10.4
Kg.h"1.m"2, respectively. For isopropanol with 95%, 53% and 33% in concentration, the flux were
1.3, 1.6 and 3.8Kg.h"1.m'2, respectively. For zirconia membrane modified by PDMS and using
ethanol as a feed solution with 95%, 52% and 30% in concentration, it was obtained a flux of 3.8,
8.8 and 8.7Kg.h~1.m"2, respectively. For isopropanol with 95%, 48% and 26% in concentration, it
was obtained flux of 5.3, 7.8 and 9.8Kg.h"1.m"2, respectively. For zirconia membrane treated with
PMMA and using ethanol as feed solution with 95%, 48% and 27% in concentration it was obtained
a flux of 2.9, 4.6 and 7.6 Kg.h"1.m"2, respectively. For isopropanol with 95%, 38% and 17% in
concentration it was obtained flux of 4.7, 5.6 and 6.3 Kg.h'Vm"2, respectively. Alumina membranes
modified by PDMS presented high selectivity to water in relation to ethanol, with value of 200. The
same behavior was obtained to zirconia membrane modified by PMMA. For zirconia membrane
modified by PDMS it was observed no selectivity for ethanol-water and isopropanol-water. This
happen due to some cracking found on the zirconia surface by scanning electron microscopy.