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UNESCO Centre for Membrane Science and Technology |
Analytical Equipment
The Centre is equipped with a wide range of analytical instrumentation for membrane characterisation and sample analysis. Some of these facilities include:HOLLOW FIBRE MANUFACTURE:
1. Polymeric hollow fibre membrane fabrication unit: Dry-jet, wet spinning
technique is adopted for polymeric hollow fibre fabrication, and the dope and
bore fluid are co-extruded from the spinneret into the air gap with ambient
conditions. Once passing through the air gap, the nascent fibres are immersed
into a coagulation bath filled with tap water at room temperature. After passing
over one wheel-guide, fibres are collected on a take-up drum with a perimeter of
1 meter and ready for further treatments.
2. Gas permeation test unit: The permeation properties of hollow fibres are measured in a high pressure set up by using the variable pressure method. This type of apparatus allows straightforward determination of membrane permeability and selectivity over a wide range of feed pressure and composition and can be applied on both pure gas permeation and mixed gas permeation. Permeate flow rate is measured by an Agilent Technologies Optiflow570 digital flow-meter while feed and permeate pressures are measured by MKS Barathron750B and 722A respectively. Gas mixture compositions are measured by a Shimadzu GC-8A gas chromatograph.
ELECTROKINETIC (STREAMING POTENTIAL) ANALYSER:
The SurPASS electrokinetic analyser (Anton Paar,
www.anton-paar.com) is
used in surface analysis to investigate the zeta potential of macroscopic
solids, and is based on streaming potential and current measurements. The zeta
potential is related to the surface charge at a solid/liquid interface and is a
powerful indicator for the surface chemistry (pH titration) and liquid phase
adsorption processes. SurPASS is used to obtain membrane surface properties and
thus assessing the effect of different operating conditions on membrane surface
charge. Zeta potential measurements have various applications in membrane
technology field, including membrane fouling characterization and modification
studies.
MEMBRANE CASTING:
In order to produce membranes by phase inversion method, it is necessary to cast
consistent films of a known, uniform thickness that can subsequently be immersed
in coagulation bath and dried or cured by the appropriate method. Historically,
hand operated applicators using casting knife have been used to apply such
films, but it is difficult to accurately judge the traverse speed of the
applicator and also maintain a constant speed, resulting in an uneven film
thickness and variation in membrane performances. The Sheen 1133N Automatic Film
Applicator provides a motorised method of driving a range of film applicators at
a known constant speed. The speed range of this instrument is from 50-500 mm/s
in increments of 10 mm/s. Using a block applicator with a gap of 0.1mm (0.004")
at 500 mm/s, shear rate of 5000 sec-1 can be obtained.
TOTAL ORGANIC CARBON ANALYSER V-CSH:
The total organic carbon (TOC) analyser (Shimadzu
TOC-VCSH & Auto-sampler ASI-V) is a fully automated and controlled device,
providing high sensitivity and productivity, capable of performing both the
“total carbon - inorganic carbon” and the “non-purgible organic carbon” method
of TOC analysis. The sample oxidation is by combustion method, offering the
choice of analysing difficult sample matrices. Auto sampler tray is capable of
accommodating 68 x 40mL vials, for uninterrupted measurement. Auto-Diluter
allows the user to create a 10-point TOC calibration curve from one standard.
High-concentration samples can automatically be reduced from 2-50 times to
reduce matrix problems and maintenance cost. The external sparge kit helps to
simultaneously analyse a sample and sparge the following sample in a NPOC
analysis.
CAPILLARY FLOW POROMETER:
Capillary Flow Porometer (model no: CFP-1200-AEXL) from PMI Porous Materials
Inc. (www.pmiapp.com) is
available in our lab. Capillary flow porometry analysis assesses membrane mean
flow pore size, bubble point, cumulative flow, and pore size distribution. The
machine can test for both flat sheet and hollow fibre samples by using different
adapter plates. The pore size range which can be detected ranges from 60 micron
down to 35 nanometres. The dry-up/wet-up mode is the most commonly used protocol
used for the porometry test.
UV-VISIBLE SPECTROPHOTOMETER:
