Separation of acetic acid and water using reverse osmosis membranes
Abstract
This study focuses on utilizing the reverse osmosis membrane to separate the acetic acid
from aqueous mixture. A commercially AG membrane and three laboratory synthesized
polysulfone (PSU) membranes were used in this work. The synthesized membranes
were prepared via phase inversion-immersion precipitation method. Two types of
polymer concentrations were chosen; 17.5 wt% PSU and 20.0 wt% PSU. It was found
that the water permeate flux of the 17.5 wt% PSU was the highest. Therefore this
membrane was selected to further modified by interfacial polymerization to form a thin
polyamide coating layer on top of the polysulfone membrane; (17.5 wt% PSU (M)). All
membranes were tested in terms of its permeation flux and rejection rate in different
type operating conditions. Dead end filtration was used to examine the membrane
performances followed by, membrane morphology analysis using Field Emission
Scanning Electron Microscopy (FESEM), and membrane functional group test by
Fourier Transform Infrared Spectroscopy (FTIR). At 10.0 wt% HAc, the commercial
AG membrane shows the highest rejection rate among all the membrane, which range
from 20%26% and at pressure range of 15 bar to 25 bar. The highest water flux was
discovers when using 17.5 wt% PSU membrane. It was observed that increasing the
pressure effectively increases the flux. The result of osmotic pressure to solute
concentration ratio demonstrated that the AG membrane has the lowest osmotic
pressure range from 15.41 m2/h2 to 17.18 m2/h2. The result of top surface and cross
sectional structure morphology showed that AG membrane and 17.5% PSU (M) consist
of a thin polyamide layer on top of the polysulfone membrane. This was proven by the
FTIR analysis. However the FESEM micrograph showed the thin film polyamide on the
modified membrane was uneven. This was among the reasons for rejection and flux
membranes percent is low compared with the membrane AG (commercial membrane