FABRICATION OF POLYSULFONE MEMBRANE, THE EFFECT OF ADDITIVE POLYVYNIL PYRROLIDOLE (PVP) ON MEMBRANE FLUX
AND REJECTION
AHMAD SYUKRI BIN BAHARUDIN @ ISMAIL
A report submitted in fulfillment of requirements for the award of the Degree of
Bachelor of Chemical Engineering
Faculty of Chemical Engineering and Natural Resources
University College of Engineering & Technology Malaysia
NOVEMBER 2006
“I declare that this thesis is the result of my own research except as cited references.
The thesis has not been accepted for any degree and is concurrently submitted in
candidature of any degree.”
Signature :…………………………. Name of Candidate :………………………… Date :…………………………
DEDICATION
Special dedication to my beloved father, mother,
brothers, sisters and all my friends……..
ACKNOWLEDGEMENTS
Bismillahirrahmanirrahim
Firstly, I would like to express my gratitude to my supervisor, Mr Mazrul
Nizam bin Abu Seman for his enduring guidance, trust, assistance and constructive
ideas. Do not forget also to all lecturers who involved directly or indirectly in
completing this research. Thank you very much for the knowledge and guidance.
Besides, I would like to thanks to the personnel at FKKSA clean room for
their assistance and cooperation, especially to Miss Idayu and Mr Masri.
My special appreciation is dedicated to my father, Hj Baharudin @ Ismail bin
Mohd, my mother, Madam Hajjah Zaharah binti Ahmad , brothers, Shahrul Alim,
Abdul Mukti ,Abdul Hakim and sisters, Nadiah and Nurul Husna for their patience,
moral and financial support during the course
Lastly, I would like to thank to my colleagues and friends for their moral
support and assistants. Thank you for being there.
ABSTRACT In the previous research, the characteristics of microfiltration membranes
showed by polysulfone membrane, the membrane was fabricated from the mixing of
polysulfone (Psf) powder, n-Methyl Pyrrolidone (NMP) as the solvent and polyvinyl
pyrrolidone (PVP) as an additive. The objective of that research is to find the
optimum of membrane in flux and rejection by changing additive percentage. The
percentage of polyvinyl pyrrolidone is the manipulative substance. The percentages
of polyvinyl pyrrolidone were increased until 14 % of the solution. The phase
inversion technique was used in fabrication process. The average pores size existing
on the membrane surfaces are 0.25 μm, and the numbers of pores depends on the
additive composition. The average of pore size will increase when the additive more
than 40 % of additive.
ABSTRAK
.Dalam kajian lepas, sifat-sifat membran microfiltration ditunjukkan oleh
membran polysulfone. Membran polysulfone dihasilkan daripada campuran serbuk
polysulfone , n-Methyl pyrrolidone (NMP) sebagai pelarut, dan polyvynil
pyrrolidone (PVP) sebagai bahan tambahan. Objektif utama kajian ini ialah untuk
mencari keadaan yang optimum untuk membran bagi flux dan penyingkiran. Dengan
mengubah peratusan PVP. Peratusan PVP merupakan pemboleh ubah dalam kajian
ini, dan peratusan PVP akan ditingkatkan sehingga 14% daripada larutan membran
polysulfone. Teknik penyongsangan fasa, merupakan proses penukaran fasa sesuatu
bahan, daripada pepejal kepada cecair dan kembali semula dalam bentuk pepejal.
Purata saiz liang pada permukaan membran adalah 0.25 μm dan jumlah liang
bergantung kepada komposisi polyvynilpyrrolidone. Macropores (2μm) akan
terbentuk pada permukaan membran, apabila larutan campuran polysulfone
mengandungi lebih 40% polyvynilpyrrolidone.
TABLE OF CONTENTS
CHAPTER TITLE PAGE
TITLE i
DECLARATION ii
ACKNOWLEDGEMENT iv
ABTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF ABBREVIATIONS xiii
1 INTRODUCTION
1.1 Introduction 1
1.2 Objective 1
1.3 Scope 2
2 LITERATURE REVIEW
2.1 Historical Development of Membranes. 3
2.2 Basic Concept of Membrane 5
2.3 Classification of Filtration Membrane 7
2.3.1 Mircofiltration membrane 9
2.3.2 Ultrafiltration membrane 11
2.3.3 Reverse Osmosis Filtration membrane 12
2.3.334
2.4 Type of membranes. 14
2.4.1 Isotropic membranes. 14
2.4.1.1 Microporous membranes. 14
2.4.1.2 Nonporous, dense membranes. 15
2.4.1.3 Electrically charged membranes. 15
2.4.2 Anisotropic membranes. 16
2.4.2.1 Ceramic, metal and liquid membranes. 16
2.5 Module types of membranes and characteristics. 17
2.5.1 Plate and frame. 17
2.5.2 Spiral-wound 18
2.5.3 Tubular 20
2.5.4 Hollow-fiber 21
2.6 Microfiltration membranes. 22
2.6.1 Types of Microfiltration membrane. 23
2.6.2 Applications Microfiltration Membranes. 25
2.6.2.1 Sterile Filtration of Pharmaceuticals. 26
2.6.2.2 Microfiltration in the Electronics
industry. 26
2.6.2.3 Blood Microfiltration. 27
2.7 Polysulfone Membranes. 28
2.7.1 Characteristic of polysulfone membrane. 28
3 METHODOLOGY FOR FABRICATION
POLUSULFONE MEMBRANE
3.1 Introduction 29
3.2 Chemicals and equipments. 30
3.2.1 Poly vinyl Pyrrolidone 30
3.2.2 Polysulfone Powder. 30
3.2.3 n-Methyl Pyrrolidone 31
3.2.4 Glass Plate 31
3.2.5 Water Bath 32
3.2.6 Nitrogen Gas 32
3.2.7 Hot Plate with Magnetic Stirrer 32
3.2.8 Uv-Visible Spectrophotometer (UV-Vis) 33
3.2.9 Millipore Stirred Ultrafiltration cells. 33
3.3 Fabrication of Polysulfone Membrane. 34
3.3.1 Mixing process. 34
3.3.2 Casting process. 35
3.3.3 Bath process 36
3.3.4 Testing process 38
4 RESULTS AND DISCUSSIONS
4.1 Introduction 40
4.2 Result 40
4.2.1 Solution preparation 41
4.2.2. Flux 42
4.2.3 Rejection of membrane 43
5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 47
5.2 Recommendations 48
REFERENCES 49
APPENDIX 51
LIST OF TABLES TABLE NO TITLE PAGE
2.1 Technically relevant membrane separation processes, 7
their operating principles and their application
2.2 Commercially available membrane module, cost and
major application. 17
2.3 Typical membrane area and number of membrane
envelopes for 10-in long industrial spiral wound
modules. 19
2.4 Comparison between screen membrane and depth
membrane. 25
3.1 Name of parts in Millipore stirred ultrafiltration cells. 39
4.1 The percentage of component in membrane solution. 41
4.2 Flux for each membrane. . 46
4.3 Absorbent for different concentration 43
4.4 Absorbent and concentration of flux. 45
4.5 Rejection for each membrane. 45
LIST OF FIGURES FIG. NO TITLE PAGE
2.1 (a) Microporous membranes separation by molecular
Filtration. 5
2.1 (b) Dense solution-diffusion membranes separate
because of diffusion in the solubility and mobility of
permeates in the membrane material. 5
2.2 The basic membrane seperation process. 6
2.3 More clearly the membrane separation process. 6
2.4 Microfiltration process. 10
2.5 Ultrafiltration membrane process. 11
2.6 Reverse osmosis filtration membrane process. 12
2.7 Flat plate module 18
2.8 Spiral wound module. 20
2.9 Tubular membrane module. 21
2.10 Hollow fiber membrane module. 21
2.11 Screen filters membrane. 24
2.12 Depth filters membrane. 24
3.1 The overall process in fabrication polysulfone
membrane. 29
3.2 The powder of polyvinyl pyrrolidone. 30
3.3 The molecule structure of polysulfone. 30
3.4 The solution of n-Methyl pyrroldione 31
3.5 Glass plate and glass rod. 31
3.6 Hot plate with magnetic stirrer 32
3.7 Uv-visible spectrophotometer (Uv-Vis) 33
3.8 Millipore stirred ulttrafiltration cell 33
3.9 The mixed solution 34
3.10 Stirring process of polysulfone and polyvinyl
pyrrolidone in n-Methyl pyrrolidone. 35
3.11 Polysulfone solution covered with aluminum foil. 35
3.12 Polysulfone solution poured onto a flat glass. 36
3.13 The solution flattens by using glass rod. 36
3.14 The liquid take off from glass plate. 37
3.15 The membrane keeps in water with room
temperature. 37
3.16 Parts in Millipore stirred ultrafiltration cells. 38
3.17 Uv-visible spectrophotometer (Uv-vis) 39
4.1 Graph flux versus pressure 42
4.2 Graph absorbent versus concentration 44
4.3 Graph rejection vs percentage of PVP. 46
LIST OF ABBREVIATIONS
PVP = Polyvinyl Pyrrolidone
MUSC = Millipore stirred ultrafiltration cells.
Uv-vis = Uv-visible spectrophotometer.
T = Temperature
t = Time
P = Pressure
ml/cm2.s = milliliter per (centimeter square multiple second)
Chapter 1
1.1 INTRODUCTION
Membrane is a device in separation process since 1748 and until now, we have
many types of membranes, for example polymer membranes, metal membrane, ceramic
membranes and in the same time, the differences of pore size of membrane will make
differences classification of membranes, like microfiltration, ultrafiltration , reverses
osmosis and etc. The most important property of membranes is their ability to control the
rate of permeation of different species. In the membrane’s separation process, we have
permeate and retentate. Permeate are separated because of the differences in the solubility
of the materials in the membranes and the differences in the rates at which the materials
diffuse through the membranes.
1.2 OBJECTIVE
The main objective for this experimental study is, to produce polysulfone
membranes and to determine the effect of polyvinyl pyrrolidone (PVP) on flux and
rejection for polysulfone membranes.
1.3 SCOPE
i) To fabricate polysulfone membrane with polyvinyl pyrrolidone (PVP) as
additive.
ii) To study the optimum percentage of polyvinyl pyrrolidone (PVP) on
membrane performance (flux and rejection )
iii) To characterize membrane by using color solution.
CHAPTER 2
ARTICLE REVIEW 2.1 HISTORICAL DEVELOPMENT OF MEMBRANE
Systematic studies of membrane phenomena can be traced to the eighteenth
Century philosopher scientists. Abbe Nolet, for example, coined the word osmosis to
describe permeation of water through a diaphragm in 1748. Through the 19th and early
20th centuries, membranes had no industrial or commercial uses. But, membrane was
used as laboratory tools to develop physical and chemical. For example, the measurement
of solution osmotic pressure made with membranes by Traube and Pfeffer were used to
the van`t Hoff in 1887 to develop his limit law, explaining the behavior of ideal dilute
solutions. (Baker, 2000)
Early membrane investigators experimented with every type of diaphragm
available to them, such as bladders of pigs, cattle or fish and sausage casings made of
animal gut. Bechhold devised a technique to prepare nitrocellulose membranes of graded
pore size, which he determined by a bubble-test method in 1907. Other later workers,
particularly Elford, Zsigmondy and Bachman, and Ferrys, improved on Bechhold’s
technique. By the early 1930s micro porous collodion membranes were commercially
available. During the next 20 years this early microfiltration membrane technology was
expanded to other polymers, particularly cellulose acetate, and membranes found their
first significant applications in the filtration of drinking water samples at the end of
World War II. (Baker 2000)
European countries, especially Germany, they have many problem about water,
water pollution, disease for drinking water and etc. This problem was affecting the water
supplies for large communities, for drinking water and for using everyday. Us army
sponsored many of capital for research in developing filters and exploited by the
Millipore Company and they can produces the largest microfiltration membrane. In early
of developing membrane technology, only a few and small laboratories used the
membrane.
The membrane technology was developing successful in 20 years, from 1960 until
1980. The original Loeb- Sourirajan membrane technology and other process were
developed for making ultra thin, high performance membrane. Interfacial and multilayer
composite casting and coating was used. In that time, to make membrane with thin 0.1
pm is impossible accept a number of company.
Methods of packaging membranes into large-membrane-area spiral-wound.
Hollow-fine-fiber, capillary and plate-and-frame modules were also developed, and
advances were made in improving membrane stability. As a result, by 1980
microfiltration. Ultrafiltration, reverse osmosis and electrodialysis were all established
processes with large plants installed around the world. The principal milestone in the
1980s was the emergence of industrial membranes gas separation processes. The first
major development was the Monsanto Prism membranes for Hydrogen separation,
introduced in 1980s, this information are in A I Schafer (2005).
2.2 BASIC CONCEPT OF MEMBRANE
The important things of membrane are their ability to control the rate of
permeation of different species. It has two models in mechanism of permeation and
Figure 2.1 (a) and 2.1 (b) show mechanism of model. One model is the solution-diffusion
model, in which permeate dissolve in the membranes material and then through the
membrane down a concentration gradient. The permeants are separated because of the
differences in the solubilities of the materials in the membrane and the differences in the
rate at which the material diffuse through the membrane. The other model is the pore
flow model, in which permeants are transported by pressure-driven convective flow
through tiny pores. In Leos J.Zeman said, separation occurs because one of the permeants
is excluded (filtered) from some of the pores in the membrane through which other
permeants move. Both models were proposed in the 19th century, but the pore flow
model, because it was closed to normal physical experiences, was more popular until
mid-1940s.
Figure 2.1 (a) Microporous membranes Figure 2.1 (b) Dense solution-diffusion separation by molecular filteration membranes separate because of diffusion in the solubility and mobility of permeants
in the membranes material
(Source: Baker 2000)
Membrane also known as selective barrier between two phases that have thin
barrier that permits selective mass transport and the phase that acts as a barrier to prevent
mass movement, but allows restricted and / or regulated passage of one or more species.
x Driving force
ΔP ΔC ΔE ΔT
FluxPermeate
Figure 2.2 The basic membrane separation process.
(Source: Lecture note, Membrane technology, 2005)
We can see more clearly in Figure 2.2 for some basic understanding on membrane
process.
Figure 2.3: shown more clearly the membrane separation process
(Source: Lecture note, Membrane technology. 2005)
We have 4 separation processes according to their pore size diameter and there
are reverse osmosis, ultrafiltration, microfiltration, and conventional filtration Membrane
was be classified according to their pore size diameter refer Figure 2.3. The pore diameter
size for reverse osmosis is 1A to 10A, Ultrafiltration is from 10A to 1000A,
microfiltration is from 1000A to 10micrometer, and lastly is conventional filtration that is
from 10micrometer to 100micrometer.
2.3 CLASSIFICATION OF FILTRATION MEMBRANE
There are some of levels for filtration membrane. Each of them has different
character such as mechanisms of separation, physical morphology and chemical nature.
Generally, there are 3 main classifications of filtration membrane. There are
microfiltration membrane, ultrafiltration membrane, and reverse osmosis filtration
membrane. Table 2.1 show the technically relevant membrane separation processes, their
operating principles, and their application.
Separation
Process
Membrane Type
Used
Applied
Driving Force
Mode of
Separation
Applications
Microfiltration symmetric porous
structure, pore radius
0.05-5 μm
hydrostatic
pressure
0.5-4 bar
filtration
(size exclusion)
water purification,
sterilization
Ultrafiltration asymmetric porous
structure, pore radius
2-10 nm
hydrostatic
pressure
1-10 bar
filtration
(size exclusion)
Separation &
fractionation of
molecular mixtures
Diafiltration asymmetric porous
structure, pore radius
2-10 nm
hydrostatic
pressure
1-10 bar
filtration &
dialysation
(size exclusion)
purification of
molecular mixtures
artificial kidney
Reverse osmosis asymmetric skin-type
solution-diffusion
structure
hydrostatic
pressure
10-100 bar
solution-
diffusion
mechanism
sea & brackish
water desalination
Dialysis Symmetric porous
or gel-type
concentration
gradient
diffusion artificial kidney
structure
Electrodialysis symmetric ion-
exchange membrane
electrical
potential
migration
Donnan-exclusion
water desalination
Donnan Dialysis symmetric ion-
exchange membrane
concentration
gradient of
individual ions
diffusion
Donnan exclusion
water softening
Electrodialytic
Water Dissociation
bipolar
membrane
electrical
potential
migration,
Donnan-exclusion
acid & base
production from
salts
Gas Separation
homogeneous
symmetric structure
vapor pressure
gradient
solution-
diffusion
oxygen/nitrogen
separation
Pervaporation homogeneous
symmetric structure
vapor pressure
gradient
solution-
diffusion
separation of
azeotropic mixtures
Vapor Permeation homogeneous
symmetric structure
vapor pressure
gradient
solution-
diffusion
recovering of
organic vapors
from air
Membrane
Distillation
symmetric porous
hydrophobic structure,
vapor pressure
gradient
diffusion liquid/solid
separation
Membrane
Contactores
symmetric porous
structure, or liquid
membrane
chemical
potential
gradient
diffusion
solution
Solvent extraction
Table 2.1: Technically relevant membrane separation processes, their operating principles, and their application. (Source: Lecture note, Membrane technology. 2005)
2.3.1 Microfiltration Membrane
Microfiltration (MF) with pore size between 0.1 and 10μm ,as figure 2.4 refers
to filtration processes that use porous membranes to separate suspended particles. Thus,
microfiltration membranes fall between ultrafiltration membranes and conventional
filters. Like ultrafiltration, microfiltration had its modern origins in the development of
collodion (nitrocellulose) membranes in the 1920s and 1930s.
In 1926 Membranes filter GmbH was founded and began to produce collodion
microfiltration membranes commercially. (Baker, 2000)
The water treatment activities are used microfiltration membranes. The objectives
of treatment is used to culture microorganism in drinking water, this remain a significant
application. The test was developed in Germany during World War II, as a rapid method
to monitor the water supply to contamination.
Microfiltration membranes are often used in applications for which penetration of
even one particle or bacterium through the membrane can be critical. Thus, the
membrane integrity, the absence of membrane defects or oversized pores, is extremely
important. From Leos J.Zeman, the characteristics of pore size for microfitration are a
problem for manufactories. Most microfiltration membranes are depth filter. The average
pore diameter of these membranes appears to be about 5 μm, yet the membranes are
complete filters for particles or bacteria of about 0.5-μm diameter. The ability of
membranes to filter bacteria from solutions depends on the pore size of the membrane,
the size of the bacteria being filtered, and the number of organisms used to challenge the
membrane.
Applications examples include:
• Water treatment (filtration of particulates and microorganisms).
• Clarification /Sterilization of beer and wine
• Cell recovery from broths.
• Removal of bacteria from milk and other food products.
• Removal fat and oil.
• Fractionation of proteins.
• Pharmaceutical sterilization.
• Clarification of juice
Figure 2.4: Microfiltration Processes
(Source: Lecture note, Membrane Technology, 2005)
2.3.2 Ultrafiltration Membrane
Ultrafiltration which have the average pore diameter of membranes from 10 to
1000 Å the pressure requirements are moderate at 1-10 bar as figure 2.6. Using a porous
ultrafiltration membrane to separate water and microsolutes from macromolecules and
colloids. The first synthetic ultrafiltration membranes were prepared by Bechhold from
collodion (nitrocellulose). Bechhold was probably the first to measure membrane bubble
points and he also coined the term ultrafilter. By the mid-1920s, collodion ultrafiltration
and microfiltration membranes were commercially available for laboratory use.
Collodion membranes were widely used in laboratory studied, no industrial
application existed until 1960s. (Baker, 2000)
From Loeb-Souriranjan process with anisotropic structures is the concept in
Ultrafiltration. They have a finely porous surface layer or skin supported on a much more
open microporous substrate. The finely porous surface layer performs the separation; the
microporous substrate provides mechanical strength. The membranes discriminate
between dissolved macromolecules of differences sizes and are usually characterized by
their molecular weight of the globular protein molecule that is 90 percent rejected by the
membranes.
Salt, Sugar
Macromolecules
Figure 2.5: Ultrafiltration Membrane Process
(Source: Lecture note, Membrane Technology, 2005)
2.3.3 Reverse Osmosis Filtration Membrane Many company of drinking water in our country used the concept of Reverse
Osmosis (RO). Reverse Osmosis (RO) is a process for desalting water that uses
membranes that are permeable to water but essentially impermeable to salt. Pressurized
water containing dissolved salts contacts the feed side of the membrane; water depleted
of salt is withdrawn as a low-pressure permeates. The ability of membranes to separate
small solutes from water has been known for a very long time. Pfeffer, Traube and other
studied osmoric phenomena with ceramic membranes as early as the 1950s. (Leos
J.Zeman)
In 1931the process was patented as a method of desalting water and the term
reverse osmosis was coined. This Reverse Osmosis has the smallest pores 0.0001- 0.001
microns and has the highest-pressure requirement 10-100 bar. Figure 2.6 show the
process of reverse Osmosis Membrane.
RO
Salt, sugar Macro-molecules
Suspensions particulates
Water
Figure 2.6: Reverse Osmosis Filtration membrane Process.
(Lecture note, Membrane Technology. 2005)
