BORANG PENGESAHAN STATUS TESIS OOI CHOW ERN

Transcription

1 PSZ 19:16 (Pind. 1/97) UNIVERSITI TEKNOLOGI MALAYSIA BORANG PENGESAHAN STATUS TESIS JUDUL : PERFORMANCE INVESTIGATION OF LOW PRESSURE REVERSE OSMOSIS MEMBRANE (LPROM) ON THE REJECTION OF ENDOCRINE DISRUPTING CHEMICALS (EDCs) SESI PENGAJIAN: 2006/ 2007 Saya OOI CHOW ERN (HURUF BESAR) mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah)* ini disimpan di Perpustakaan Universiti Teknologi Malaysia dengan syarat-syarat kegunaan seperti berikut : 1. Tesis adalah hakmilik Universiti Teknologi Malaysia. 2. Perpustakaan Universiti Teknologi Malaysia dibenarkan membuat salinan untuk tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan ( ) (Mengandungi maklumat yang berdarjah keselamatan atau SULIT kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972) TERHAD TIDAK TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) Disahkan oleh (TANDATANGAN PENULIS) Alamat Tetap: 50, JALAN MUHIBBAH, PARIT BUNTAR, PERAK DARUL RIDZUAN. TARIKH : 20 APRIL 2007 (TANDATANGAN PENYELIA) EN.MOHD.BINNOOR OTHMAN Nama Penyelia TARIKH : 20 APRIL 2007 CATATAN: * Potong yang tidak berkenaan. ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/ organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD. Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).

2 I declare that this thesis entitled Performance Investigation Of Low Pressure Reverse Osmosis Membrane (LPROM) on the Rejection of Endocrine Disrupting Chemicals (EDCs) is the result of my own research except as cited in the references. The thesis has not been accepted for any degree and is not concurrently submitted in candidature of any other degree. Signature: Supervisor s Name: Date:. EN. MOHD. BIN NOOR OTHMAN.

3 i PERFORMANCE INVESTIGATION OF LOW PRESSURE REVERSE OSMOSIS MEMBRANE (LPROM) ON THE REJECTION OF ENDOCRINE DISRUPTING CHEMICALS (EDCs) OOI CHOW ERN This report is submitted in fulfilment of the requirement for the award of the degree of Bachelor of Civil Engineering Faculty of Civil Engineering Universiti Teknologi Malaysia April 2007

4 ii I pledge that this thesis is my original work except the quotations and summaries that I have stated the sources clearly Signature: Name: Date:.. OOI CHOW ERN..

5 iii Dedicated to my beloved parents, sisters, Aunt Kathy, and friends. Thanks for all your love and support.

6 iv ACKNOWLEDGEMENT Firstly, I would like to express my greatest gratitude to my supervisor, Mr. Mohd. bin Noor Othman. His kind guidance, patience, valuable suggestions and advices have been a great help to me throughout the preparation and completion of this project. I also want to draw my appreciation to my supervisor for spending his valuable time to check my dissertation. Sincere thanks are extended to Mr. Azri Rasyidi Abdul Razak and Ms. Joan Dolly Chung Zie Wei for their assistances, strong backing, and knowledge sharing in conducting the experimental design and laboratory works. I would also like to thank them for their worthful advices and guidance in my dissertation writing. Deepest gratitude is expressed to my parents, families and friends because of their warmest support and encouragement throughout the study. Lastly, thank you to everyone who had contributed, either directly or indirectly for the completion and success of this study.

7 v ABSTRACT Membrane technologies are emerging as alternatives to conventional water treatment and as a means of filtering treated wastewater effluent for reuse applications. Among all the membrane technology, reverse osmosis (RO) is the most common-used process in water treatment due to its capability in removing a large variety of contaminants including organic chemicals, bacteria, particulates and etc effectively. However, low pressure reverse osmosis membrane (LPROM) recently stands out as better alternative because of its better rejection ability and operates at lower pressure compared to RO system. Because of the lower pressure requirement, the energy consumption of LPROM will be lower and thus it is more cost effective than RO system. In this study, the performance of LPROM was investigated in term of the rejection of Endocrine Disrupting Chemicals (EDCs) by varying three operating parameters: concentration, pressure, and ph. The synthetic EDCs samples used in this study are 17-beta Estradiol and Bisphenol A. In this study, it was experimentally shown that the rejection of both samples is influenced by concentration, operating pressure. The rejection of both samples increases when the values of both of the parameters are being raised. On the other hand, the flux increased as the pressure applied is being increased. The results of both samples display a high rejection percentage range indicating that membrane used has high efficiency in removing the two samples. The rejection percentages of Bisphenol A are higher than 17-beta Estradiol. This is probably due to the solubility of Bisphenol A which is lower compared to 17-beta Estradiol.

8 vi ABSTRAK Teknologi membran sedang berkembang sebagai alternatif kepada rawatan air kovensional dan sebagai suatu cara untuk menapis air sisa yang telah dirawat bagi tujuan penggunaan semula. Di antara semua teknolgi membran, osmosis songsang (RO) merupakan proses yang paling biasa digunakan disebabkan keupayaannya dalam menyahkan pelbagai jenis bahan cemar mikro termasuk bahan kimia organik, bakteria, zarah-zarah dan sebagainya secara efektif. Membran osmosis songsang tekanan rendah (LPROM) muncul sebagai alternatif yang lebih baik disebabkan kebolehan penyahan yang lebih baik and ia memerlukan tekanan yang lebih rendah untuk beroperasi dibandingkan dengan sistem osmosis songsang (RO). Disebabkan keperluan tekanan yang lebih rendah, penggunaan tenaga bagi LPROM akan menjadi lebih rendah, oleh itu ia lebih kos efektif jika dibandingkan dengan sistem RO. Dalam kajian ini, prestasi LPROM diselidik dalam konteks menyahkan Endocrine Disrupting Chemicals (EDCs) dengan mengubah-ubah tiga parameter: kepekatan, tekanan, dan ph. Sampel sintetik EDCs yang digunakan dalam kajian ini ialah 17-beta Estradiol dan Bisphenol A. Dalam kajian ini, sudah ditunjukkan secara eksperimen bahawa penyahan bagi kedua-dua sampel dipengaruhi oleh faktor kepekatan dan tekanan operasi. Penyahan bagi kedua-dua sampel meningkat apabila nilai kedua-dua parameter ditingkatkan. Di samping itu, aliran meningkat apabila tekanan dikenakan meningkat. Keputusan bagi kedua-dua sampel mempamerkan lingkungan peratus penyahan yang tinggi menunjukkan bahawa membran yang digunakan mempunyai kecekapan yang tinggi dalam menyahkan kedua-dua sampel. Peratus penyahan bagi Bisphenol A adalah lebih tinggi dibandingkan dengan 17-beta Estradiol. Ini mungkin disebabkan oleh keterlarutan Bisphenol A adalah lebih rendah dibandingkan dengan 17-beta Estradiol.

9 vii TABLE OF CONTENTS CHAPTER TITLE PAGE TITLE OF PROJECT DECLARATION DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF APPENDICES i ii iii iv v vi vii x xi xiii xiv 1 INTRODUCTION Research Background Objectives Scope of Study Significance of Study 4 2 LITERATURE REVIEW General Description of Endocrine Disrupting Chemicals (EDCs) Action Mechanism of EDCs Effects of Endocrine Disrupting Chemicals (EDCs) 10

10 viii 2.2 Previous Study Membrane Technology Reverse Osmosis Low Pressure Reverse Osmosis Membrane Factors Affecting Performance of LPROM Effects of Feed Concentration Effects of Operating Pressure Effects of ph Future application of LPROM 21 3 METHODOLOGY Experimental Set Up Design of Experiments Preparation of Synthetic Polluted Water Experimental Procedures Data Analysis Flux Rejection Recovery Rate 34 4 RESULTS AND ANALYSIS Introduction Results and Discussion of 17-beta Estradiol Effects of Operating Pressure Effects of Concentration Effects of ph Results and Discussion of Bisphenol A Effects of Operating Pressure Effects of Concentration Effects of ph Comparison on the Rejection of 17-beta Estradiol and Bisphenol A 48 5 CONCLUSIONS AND RECOMMENDATIONS 50

11 ix 5.1 Conclusion Recommendations 51 REFERENCES APPENDICES 58-60

12 x LIST OF TABLES TABLE NO. TITLE PAGE 2.1 Sources of EDCs and Their Pathway to Waterways General descriptions of RO, NF, UF and MF Membranes Specifications of LPROM unit Coding System Experimental Run Order for Both Samples (17-beta Estradiol and Bisphenol A) Experimental results in terms of flux and rejection of 17-beta Estradiol Experimental results in term of flux and rejection of Bisphenol A Comparison of Rejection Range of Both Samples 48

13 xi LIST OF FIGURES FIGURE NO. TITLE PAGE 2.1 Showing Hormone Agonist / Antagonist / Mimic Membrane Concept Schematic Diagram of the experimental set up of LPROM LPROM System in Laboratory Schematic Diagram of C10-T module and the Illustration of the Membrane Arrangement Methodology of Performance Investigation Experiment of Low Pressure Reverse Osmosis Membrane The Effect of Pressure on Flux for 17-beta Estradiol The Effects of Pressure on Rejection Percentage for 17-beta Estradiol The effects of Concentration on Rejection Percentage for 17-beta Estradiol 40

14 xii 4.4 The Effects of ph to Rejection Percentage for 17-beta Estradiol Effects of Pressure on Flux for Bisphenol A Effects of Pressure on Rejection Percentage for Bisphenol A Effects of Concentration on Rejection Percentage for Bisphenol A Effects of ph on Rejection Percentage for Bisphenol A 47

15 xiii LIST OF SYMBOLS LPROM - Low pressure reverse osmosis membrane MF - Microfiltration UF - Ultrafiltration NF - Nanofiltration RO - Reverse osmosis EDCs - Endocrine discupting chemicals P - Operating pressure Cf - Feed concentration NACl - Sodium chloride Cp - Permeate concentration PCBs - Polychlorinated biphenyls DDT - Dichloro-diphenyl-trichloroethane PAH - Polycyclic aromatic hydrocarbon HCB - Hexachlorobenzene CDC - Centers for disease control and prevention EDTA - Ethylenediaminetetraacetic acid Zn 2+ - Zinc Cu 2+ - Copper zpc - Zero potential charge COD - Chemical oxygen demand TSS - Total Suspended Solid UV - Ultraviolet HCL - Hydrochloric acid pka - Acid dissociation constant

16 xiv LIST OF APPENDICES APPENDIX TITLE PAGE A Pressure Gauge 58 B Membrane ES20 mounted in the crossflow module C-10T 58 C Magnetic Sterile 59 D Pump 59 E Flow Meter 60 F ph Meter 60

17 CHAPTER I INTRODUCTION 1.1 Research Background Water or can be known as universal solvent is a tasteless, odorless substance in its pure form. Water plays a crucial role in daily life of all known forms of life. However today, the global is facing the severe stress on clean and sustainable water availability. Natural aquatic system, including sources of drinking water in many places, especially in developing countries, have been contaminated by various kind of recalcitrant or hazardous substances such as natural organics, pesticides, endocrine disrupting chemicals and toxic organics, due to insufficient domestic and industrial sewage treatment to illegal dumping (Ozaki et al., 2002). Those contaminating substances can be classified as micropollutants. Among the various groups of micropollutants identified, scientific and environmental attention is currently focused on endocrine disrupters chemical (EDC) an exogenous substance or mixture that alters functions of the endocrine system and causes adverse health effects in an intact organism, or its progeny, or (sub) populations. By way of addition, EDCs are also exogenous substances that can affect the normal

18 2 function of organism's hormonal system at very low concentrations in human bodies (Ozaki, 2004). The existence of EDCs in nature water sources will threaten the health of humans and wildlife. In general, the developing organisms are more susceptible to the effects of EDCs than adults. The adverse health effects caused by EDCs including abnormalities in reproduction, feminization, growth and development, impairs the functions of immune and nervous system, and cancer. These health effects also exist in animal studies which are conducted on a variety of invertebrates, reptiles, birds, fish, and mammals. For instance, Dioxin, a type of EDC which can cause liver to produce a kind of metabolic enzyme where its induction at certain level will cause immune system toxicity in mice and reproductive effects in rats (McKinney JD and Waller CL, 1994) Due to the harmful effects induced by the micropollutants, water treatment technology is focusing on producing clean and sustainable water supplies. Conventional water treatment system cannot remove the micropollutants effectively because it is not designed to attain such treatment objective. Therefore, new technology is demanded to produce high quality drinking water. Membrane technologies are receiving special recognition as alternatives to conventional water treatment and as a means of polishing treated wastewater effluent for reuse applications. Due to the imposition of new water quality requirements that exceed the capabilities of existing treatment processes, membranes are now costcompetitive alternatives for many treatment applications. In addition, membrane technology operates without the addition of chemicals, with relatively low energy consumption, and easy and well-arranged process conductions. Membrane technology utilizes a semi permeable membrane for the separation of suspended and dissolved solids from water. Basically, the pressure driven membrane technologies consists four types which are microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO).

19 3 Among all the membrane technology, reverse osmosis (RO) is the most common-used process in water treatment. RO system can remove a large variety of contaminants including organic chemicals, inorganics, bacteria and particulates effectively. However, RO system consumes high energy because of the high operating pressure and requires extensive pretreatment. The disadvantages of RO membrane have eventually led to the development of Low Pressure Reverse Osmosis Membrane (LPROM) which is a more cost effective system. LPROM has the ability to remove almost all the micropollutants in the water bodies. It operates effectively in the range of below 100 psi, which is considered as low pressure. LPROM operates at a very low pressure but provide a high flux and at the same time maintaining a very good salt and organics rejection (Hofman et al., 1997; Ozaki and Li, 2002). The energy consumption of LPROM system will be definitely lower since the operating pressure is lower. The improvement of LPROM will cause the membrane technology becomes more affordable and its application will be wider. 1.2 Objectives The main purpose of this proposed study is to investigate the performance of LPROM system which is used to remove the Endocrine Disrupting Chemicals from contaminated water sources in order to produce the harmless and high quality drinking water. The objectives are listed as below: i. To investigate the performance of LPROM under 3 operating experimental parameters, which are pressure, concentration, and ph on the rejection of 17- beta Estradiol.

20 4 ii. To investigate the performance of LPROM under 3 operating experimental parameters, which are pressure, concentration, and ph on the rejection of Bisphenol A. iii. To compare the effectiveness of LPROM on rejection of 17-beta Estradiol and Bisphenol A. 1.3 Scope of Study The scope of this study is on the performance investigation of LPROM in rejecting EDCs under three varying parameters which are feed concentration, operating pressure, and ph. The experiments will be conducted by using two synthetic polluted water samples which containing EDCs (17-beta Estradiol and Bisphenol A). The rejection of other organic or inorganic substances besides the two EDCs samples will not be included in this study. For the comparison of both samples, the main focus will be on the percentage of rejection of each substance. 1.4 Significance of Study: The deficiency of clean and safe water supplies is now becoming a global concern. This phenomenon is eventually caused by the human activities such as industrial development, producing a great amount of hazardous wastes which eventually leads to water pollution. Besides these waste materials, natural water is also contaminated by numerous types of fractious substances (i.e. EDCs, pesticides, and toxic organics) which can be classified as micropollutants.

21 5 The significances of the study are listed as below: i. The removal of micropollutants using conventional water treatment system is less efficient because the system does not design to fulfill such purpose. ii. The membrane technology, especially RO system is gaining popularity due to the increasing demand for effective water treatment system to produce high quality drinking water. iii. RO system needs to operate under a fairly high pressure, thus it can be deemed as uneconomical in term of cost. In addition, the maintenance of the system is costly too. iv. The LPROM system is capable in removing various contaminants including micropollutants due to the fact that it has RO filtration range. v. The LPROM system is more affordable and cost effective with lower energy consumption.

22 CHAPTER II LITERATURE REVIEW 2.1 General Description of Endocrine Disrupting Chemicals (EDCs) Water pollution is a global plague that affects all the life forms on this earth. Natural water resources such as rivers and lakes have been contaminated by many types of pollutants. These pollutants contain many synthetic chemicals which will seriously affect the health of either human or animals. Some of these synthetic chemicals interfere with endocrine system of the organism which is exposed to those pollutants. These types of synthetic chemicals are known as EDC. EDC can be defined as the anthropogenic compounds that are able to mimic, antagonize, alter or modify normal hormonal activity (Kretschmer and Baldwin, 2005). Besides, EDC can enter human and animal body through the food and water intake and can interfere with the normal function of hormones even at very low concentration (Ozaki, 2004). After the publication of Rachael Carson s Silent Spring in 1962, EDCs which have significant impact on human and ecological health has captured the public s attention.

23 7 Some of the most well-known examples of EDCs are 17-alpha ethinyl oestradiol (the contraceptive pill), Dioxins, PCBs, PAHs, furans, phenols and several pesticides (most prominent DDT and its derivatives). EDCs enter the environment through the disposal or release of human use and production. Then certain processes like agricultural runoff, wastewater discharges, and atmospheric deposition may bring EDCs into groundwater basin, rivers, food products, soil, and etc.

24 8 8 Table 2.1 : Sources of EDCs and Their Pathway to Waterways Category Prescription and non-prescription drugs Household products Industrial chemicals and metals Fungicides Herbicides Insecticides Examples Birth control pills, steroid-based medications, chemotherapy medications Detergents, surfactants, and their breakdown products Polybrominated diphenyl ethers, bisphenol-a, PCBs, phthalates, styrenes, mercury, lead, dioxins Hexachlorobenzene, maneb, tributyltin 2,4-D, 2,4,5-T, atrazine Carbaryl, chlordane, dieldrin, lindane, parathion Primary Pathway to Waterways Drugs partially metabolized in the body. Remaining drug and metabolites excreted in urine and feces. Wastewater treatment facilities may partially remove or breakdown these chemicals. Remainder of drugs and metabolites discharged to surface water. Improper disposal of leftover medication. Commonly rinsed down sinks and flushed down toilets. Wastewater treatment facilities may partially remove or breakdown these chemicals. Remainder of compounds and breakdown products discharged to surface water. Discharged to the sewer from industrial and commercial facilities and from households. Wastewater treatment facilities may partially remove and/or breakdown these chemicals. Remainder of compounds and breakdown products discharged to surface water Outdoor uses lead to runoff into storm drains which drain directly to surface waters in subsequent rainstorms. Indoor uses or the cleaning of contaminated equipment and clothing leads to discharge to the wastewater treatment plant where partial removal or breakdown may occur. Remainder discharged to surface water. Outdoor uses lead to runoff into storm drains which drain directly to surface waters in subsequent rainstorms. Indoor cleaning of contaminated equipment and clothing leads to discharge to the wastewater treatment plant where partial removal or breakdown may occur. Outdoor uses lead to runoff into storm drains which drain directly to creeks and the Bay. Indoor uses or the cleaning of contaminated equipment and clothing leads to discharge to the wastewater treatment plant where partial removal or breakdown may occur. Remainder discharged to surface water. Animal husbandry products Steroid-based supplements to increase milk, egg and meat production Drugs are partially metabolized in animal s body. Remaining drugs and metabolites are excreted in urine and feces where they run off to surface waters. (Source : Watershed Management Initiative, Information Sheet 2003)

25 Action Mechanism of EDCs Hormone is a chemical messenger circulating in bloods produced by an endocrine gland. It regulates certain critical biological functions via intricate signaling mechanism. Many different hormones are produced in body but each of them has its own receptor on specific cells. Hormone-receptor attachment can be described as a key fits into a particular lock. For normal condition, such attachment will initiate certain responses which will lead to a biochemical reaction or chemical production in the cell. EDCs are able to mimic or block a naturally-occurring hormone. A hormone mimic is a chemical which is very similar to natural hormone and able to create a hormone-like effect. It creates this effect by attaching to the receptor and triggers the same sequences of events like the natural hormone. Even if the hormone mimic not succeed in initiating a biochemical response, the attachment will block the receptor from occupancy by the natural hormone, acting as a hormone antagonist (as shown in Figure 2.1). Figure 2.1 : Showing Hormone Agonist / Antagonist / Mimic (Generation at Risk)

26 Effects of Endocrine Disrupting Chemicals (EDCs) The last two decades, in particular, has witnessed a growing scientific concern, public debate, and media attention over the possible deleterious effects in humans and wildlife, which may result from exposure to chemicals that have the potential to interfere with the endocrine system or which is also known as EDCs. There are lots of articles written on the adverse impacts causing by EDC on the health and biological growth of animals. Previous study in 1930 had discovered that EDC is a substance that able to mimic the endogenous hormones in animals (Cook et al., 1934; Walker and Janney, 1930). Besides, synthetic substances such as DDT has caused deformation of sex organ and skewed sex ratios of gull population living in areas contaminated with DDT (Fry and Toone, 1981; Fry et al., 1987). A growing body of scientific evidence indicates that a number of chemicals to which humans are in contact with, including PCBs, DDT, dieldrin, toxaphene, mirex, methylmercury, benzo[a]pyrene, HCB, furans, dioxins, and alkylated lead, many of which are found in high levels in the Great Lakes, may interfere with the endocrine system, potentially causing adverse effects to both wildlife and humans (Solomon and Schettler, 2000). There are indications for an increase in the incidences of some hormonally sensitive carcinomas, decrease in sperm count and quality, and increased obesity and earlier puberty occurring in girls, as well as altered physical and mental development in children (Solomon and Schettler, 2000). The levels of chemicals in the environment and the consequent burden of exposures appear to coincide with the incidence and trends of many of these adverse health outcomes. There is growing evidence to suggest that exposure to endocrine disrupting chemicals may be associated with a predisposition to obesity later in life (Heindel, 2003; Sakurai et al., 2004).

27 11 A recent literature survey on the 48 EDCs classified by the Centers for Disease Control and Prevention (CDC) was conducted to systematically analyze the toxicological characteristics of EDCs in pesticides, industrial chemicals, and metals (Choi et al., 2003). The result of the survey concluded that EDCs produce developmental toxicity, carcinogenicity, mutagenicity, immunotoxicity, and neurotoxicity (Choi et al., 2004). Regarding the hormone-disrupting effects of the 48 EDCs, estrogenic effects were the most predominant in pesticides, while effects on thyroid hormone were found for heavy metals. EDCs showing estrogen-modulating effects were closely related to carcinogenicity or mutagenicity with a high degree of sensitivity (Choi et al., 2003; Datson et al., 2003). According to the study of Choi et al, 2004, exposure to chemical toxicants plays a significant role in negative reproductive effects in humans. In men, hypospadias, cryptorchidism, cancer of the prostate, testicular cancer, and semen quality, while in women breast cancer, cystic ovaries, and endometriosis have all been suggested as indicators of adverse trends in reproductive health (Choi et al., 2004). In addition, exposure to certain EDCs (2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin and PCBs) has been associated with endometriosis, yet a clear association remains equivocal (Mayani et al., 1997). Although endocrine disruption in humans by pollutant chemicals remains largely undemonstrated, the underlying science is solid and the potential for such effects is real. 2.2 Previous Study The membrane technology appears to be a possible as well as reliable, safe and economically justified alternative for conventional water treatment and reuse system due to its advancement and reduction of its costs. The experimental investigation of Ujang and Anderson (1996) illustrated the feasibility of using a low pressure RO process for the removal of Zn 2+ and Cu 2+ from wastewater with EDTA as a chelating

28 12 agent. The study of Redondo (2002) presented the trends of using RO to treat low quality feed water and discussed alternatives and problems seen in implementing some of the possibilities. The development of membrane technology has led to the creation of a lower pressure driven membrane. The study of Nemeth (1998) stated that LPROM was the new developments introduced in the late 1980s and the mid-1990s which eventually becoming popular and known as softening membrane with high rejection ability. A study was done has illustrated the feasibility of using LPROM system (below 100 psig) for the removal of metal ions (Zn2+ and Cu2+) form their solvents with the presence of EDTA as a chelating agent (Ujang and Anderson, 1996). In addition, Ozaki et al. (2005) studied the removal of EDCs from the feed water using LPROM. Based on the results obtained, it showed that the rejection of EDCs increased with relatively loose membrane with the increases of solution ph. Another experimental investigation done by Ujang and Anderson (1998) illustrated the performance of LPROM for separating mono and divalent ions. The result shows that the higher the operating pressure, the permeate flux for heavy metals from both monoand divalent anions will be greater. Apart from that, Ujang and Anderson (2000) also studied about the application of LPROM for removal of heavy metals. The investigation particularly focused on the effects of operating parameters on the separation of metal chelates. The result shows that the most decisive parameters that affect the permeate flux variation are temperature, operating pressure and concentration of EDTA in the feed solution. All the studies scientifically proved that membrane technology is a better alternative in wastewater treatment compared to conventional water treatment system in term of efficiencies, cost, and energy consumption.

29 Membrane Technology Membrane technology is the application of a positive barrier or film in the separation of unwanted particles, micro-organisms and substances from water and effluents. Membrane technology is gaining popularity due to its ability to remove organic and inorganic substances, micropollutants such as EDCs, pathogen, and some harmful chemicals which cannot be removed by conventional water treatment system. A membrane is a thin, typically planar structure or material that selectively controls the mass transport between two environments or phases. Organic polymers, metals, ceramics, layer of chemicals, liquids and gases can be membrane. The basic concept of a membrane is illustrated in Figure 2.2. First of all, feed stream enters the membrane system. Then a driving force (e.g. pressure, concentration, electromagnetic field, etc) is applied across the membrane. This will cause certain components to permeate through the membrane while other components stay or permeate very slowly. Figure 2.2 : Membrane Concept (Charles M.Mohr et al., 1989)

30 14 The main characteristics that provide transport across the barrier (membrane) are flux and selectivity properties. Flux is the rate of flow of energy or particles across a given surface such as membrane while selectivity can be defined as ratio of permeation rates (from a more permeable material to the less permeable one). These two characteristics also used to determine the effectiveness of any membrane process. The permeation of the membrane is influenced mainly by the physical structure of the membrane and the chemical potential gradient. Membrane separation processes have various advantages compared to the conventional treatment processes according to Cartwright (1992) and Rachwal et al. (1994). Firstly, the operations of membrane system are simple, reliable and automated. Apart from that, the system can be upgraded easily with low maintenance requirements and minimum sludge disposal. The system also has compact and modular construction with minimum of moving parts. Therefore it is suitable to small systems and distributed locations. Nevertheless, the membrane itself is an absolute barrier to particles and pathogens so the system able to produce constant filtered water quality irrespective of feed water quality. Lastly, no chemicals are required to be added during the membrane separation processes. Normally, the most common pressure-driven membrane processes for water treatment are Reverse Osmosis (RO), Nanofiltration (NF), Ultrafiltration (UF), and Microfiltration (MF). Table 2.2 below will describe some characteristics of these four types of membranes

31 15 Table 2.2 : General descriptions of RO, NF, UF and MF membranes. Particulars Reverse Osmosis (RO) Nanofiltration (NF) Ultrafiltration (UF) Microfiltration (MF) Pore Size No-detectable pore size 2-5 nm 3-10 nm 10 nm-1 um Retain Particulars (MW) <350 >150 1, ,000 >300,000 Applied Pressure 1-10 MPa MPa MPa MPa Material Aromatic polyamide Cellulose acetate Aromatic polyamide Polyvinyl alcohol Polysulfone Polyimide Polyacrynitrile Ceramics Polyethylene Polyplopylene Polyvinylidenflouride Ceramics Main Function Desalination of backish and seawater. Production of ultra pure water. Removal of micropollutants. Desalination of backish water. Concentration on chemicals. Drinking water production. Clarification of fruit juice. Membrane bioreactor. Home water purifiers. Removal of fine particles and bacteria. Pre-treatment for RO and UF. Membrane bioreactor. (Source: Ozaki, 2004) 2.4 Reverse Osmosis Reverse osmosis is a process that reversing the natural phenomenon of osmosis with the pressure applied on the concentrated solution permeating through a semipermeable membrane. An ideal semi-permeable membrane is a membrane which is

32 16 permeable to solvent but not to solute. In osmosis process, net movement of solvent is from the less-concentrated (hypotonic), to the more-concentrated (hypertonic) solution under normal osmotic pressure, which tends to achieve equilibrium in term of concentration. If a pressure greater than the osmotic pressure is applied to the solution, the solvent will flow through the membrane from the solution side to the pure solvent side. Thus, this process will result in a dilute solution to be appeared on the opposite side of the membrane while the solution at the side where the pressure is applied to will become more concentrated. However, no permeation will occur through the membrane if the applied pressure is equal to the solution s natural osmotic pressure. If the pressure applied is less than its natural osmotic pressure, there will be flow from the dilute solution to the concentrated solution which it is the normal osmosis process. Basically, the permeation rate of water flux through the membrane depends on several criteria such as membrane properties, the difference in applied pressure across the membrane, less the difference in osmotic pressure between the concentrated and dilute solutions, and lastly is the temperature of the solution. 2.5 Low Pressure Reverse Osmosis Membrane Traditional RO system is an effective water treatment technology in removing organic matters from water bodies, especially the organic compounds which are low concentration and with low molecular weight. Nevertheless, the operation of this system requires high pressure and consumes high energy. Furthermore, the high operation cost and maintenance are also the factors limiting the application of RO system.

33 17 Apart from that, RO membrane has high susceptibility to fouling (Gerard et al., 1998). That means extensive pre-treatment is needed for water with high fouling potential before it is treated using RO membrane. This will eventually increase the operation cost. Even after going through a complete pre-treatment, the dissolved organic compounds remain in the water will cause problems to the conventional RO membranes. In addition, the product water lack of hardness and has an adverse effect on taste and tends to increase the rate of corrosion in pipes (Minett, 2003). Thus, ph adjustment is demanded for the treated water. Due to the disadvantages displayed by the conventional RO membrane, LPROM a type of membrane which is more cost effective with lower pressure requirement is developed. LPROM, which can be classified as a new type of NF membrane, have received attention especially for their application in the field of water purification and wastewater treatment (Ozaki, 2004). According to the studies of Ozaki and Li (2002), the LPROM mostly are multilayer thin film composites of polymers and its active surface layer normally consist of negatively charged sulphone or carboxyl group. The active surface layer helps the membranes in improving the fouling resistance against hydrophobic colloids, oils, proteins, and other organics. LPROM operates at a very low pressure but provide a high flux and at the same time maintaining a very good salt and organics rejection (Hofman et al., 1997; Ozaki and Li, 2002). In order to increase water flux, a charged support membrane is attached to a hydrophobic UF support membrane (Raman et al., 1994). Besides that, LPROM normally has the corrugated skin surface that can improve flux significantly (Ozaki and Li, 2001). Under low operating pressure ( MPa), ULPRO produces specific flux of more than 60 l/m 2 h MPa (flux per membrane area and per net driving pressure) (Ozaki and Li, 2001). This flux rate is about double the flux of previous generations of composite RO membrane (Minett, 2003).

34 18 Due to the lower pressure required, the energy consumption of LPROM system will be definitely lower. According to the calculations done based on the specifications of LPROM, the result indicates that the energy consumption could be 30-40% lower than conventional RO membranes (Hofman et al., 1997). For the same membrane surface area, under the same driving pressure, the LPROM produced twice as much permeates as the conventional membrane (Nemeth, 1998). The improvements of the LPROM will help to produce cleaner and safer drinking water which will be able to meet the stringent standards or regulations. In addition, the lower energy requirement and fouling resistance improvement will reduce the cost correspondingly. 2.6 Factors Affecting the Performance of LPROM There are several operating parameters or factors need to considered and controlled to investigate the performance of LPROM in order to produce high water flux and high rejection rate of organic substances. The efficiency of LPROM is basically under the influence of parameters like operating pressure, ph, feed concentration, and types of membrane used Effects of Feed Concentration Based on the previous study done by Ozaki et al., (2002), it can be ascertained that the effect of concentration polarization is more pronounced in the high feed

35 19 concentration. Furthermore, the effect of intermolecular repulsion is higher. These two effects will result in high removal rate but produce lower solute flux. Concentration polarization refers to the build up of solute species at the membrane surface that adversely affects the membrane performance (Wu et al., 2004). Concentration polarization increases the osmotic pressure at the membrane surface, which causes a reduction in water flux and increase in salt transport across the membrane (Bhattacharya and Williams, 1992; Lee et al., 2004; Peeva, 2004). If the concentration of sparingly soluble salts in the boundary layer exceeds their solubility limits, precipitation or scalling will occur on the membrane surface (Baker, 2000). At such higher concentration, colloidal materials become less stable and may agglomerate and cause fouling on the membrane surface (Lee et al., 2004). Higher feed concentration produces high rejection but the permeate concentration is also high. In a conclusion, removal rate increases with an increase in feed concentration (Ozaki et al., 2002) Effects of Operating Pressure The rejection rate of LPROM increases when the operating pressure applied is increased (Ozaki et al., 2002). The study of Wu et al. (2004) had also reviewed that the increment in operating pressure will result in the increases of efficiency of the NF membrane in term of rejection and the flux will increase as well. The permeate flux for heavy metals from both mono and divalent anions will be greater when higher pressure is applied (Ujang and Anderson, 1998). The study of Ku et al., (2004) also showcased that the permeate flux increases linearly with the increasing of pressure applied.

36 20 Besides that, the permeate flux is proportional to the trans-membrane pressure or the membrane operating pressure. At higher pressure, the average pore size on the membrane surface decreased and the preferential sorption of pure water increased (Ozaki et al., 2002). Another previous study also presented that the solvent permeability increases compared to solute at high pressure resulting in increased rejection (Sourirajan, 1970) Effects of ph The LPRO membrane layer consists of charged chemical groups which are carboxyl and amine groups (Ozaki and Li, 2001; Ujang et al., 2005).The membrane is negatively charged at a ph above than 5 due to the dissociation of the carboxyl group but positively charged at a ph lower than 5 as a result of the dissociation of the amine groups in the skin layer (Ujang et al., 2005).Other than that, Ozaki et al. (2002) mentioned that LPROM also has the isoelectric point or zero potential charge (zpc) in a certain ph range Thus the rejection will decrease with feed ph and then increased after a minimum point was reached. This phenomenon happens probably due to the surface charge effect of the membrane. At higher ph, metal ions are capable of forming complexes with OH- ions and lead to the formation of the insoluble hydroxide (Ozaki et al., 2002). As the result of that, the molecules of the solute become larger and will face more difficulties in permeating through membrane surface.

37 Future Application of LPROM In Malaysia, LPROM still appears as a new technology and its application is not obvious. In foreign country, this technology has been applied extensively in cleaning production fields. For instance, in Heemskerk, Netherlands, LPROM is chosen as the water treatment technology utilized at the water treatment plant (Hofman et al., 1997). LPROM is found to be capable in removing various types of micropollutants including EDCs. There are several potential fields of which the application of LPROM will be included have been identified (Mohammad et al., 2004). The first potential application is on the treatment of wastewater produced in the fish industry. From the study carried out, LPROM was able to remove COD and TSS up to 93 % and 87 % respectively. Furthermore, the recovery of protein was also proven to be possible without causing any severe membrane fouling. It is recommended that the membrane treatment system is incorporated with conventional pre-treatment or post treatment process in order to reduce the COD and TSS in the wastewater produced in fish industry more effectively. The second potential application of LPROM is for the treatment of wastewater generated by plating plant. The wastewater from a particular plating industry was found to contain several cations including nickel, zinc, and sodium (Mohammad et al., 2004). Based on the previous study, LPROM has been proven to be capable in rejecting heavy metals effectively (Ujang and Anderson, 1998). The other identified possible application of LPROM is for the treatment of leachate generated from landfill site (Mohammad et al., 2004). In this study, several samples of leachate from various landfills had been analyzed to cognize their compositions. The leachate was found to contain high COD, ammonia-nitrogen, and conductivity content. The membrane was able to remove more than 85 % of TSS, heavy metals, conductivity content and COD. However, the rejection of nitrate and ammonia

38 22 is lower which was found to be 45.4% and 20.4% respectively. Based on the results displayed, LPROM can be applied to treat leachate incorporated with other suitable conventional treatment system.

39 CHAPTER III RESEARCH METHODOLOGY 3.1 Experimental Set Up The objective of this experiment is to evaluate the efficiency of commercial LPRO membrane (ES20) in rejecting EDCs. ES20 membrane which was used throughout the experiment is a multi-layer thin film composite of aromatic polyamide manufactured by Nitto Denko company. The membrane used was supplied in a flat sheet form. It was mounted in the crossflow module C-10T and the effective membrane surface area of the module is 60cm 2. There are charged chemical groups (carboxyl groups and amine groups) exist at the active membrane layer. The dissociation of the carboxyl group in the skin layer will cause ES20 membrane becomes negatively charged at ph above 5. On the other hand, dissociation of the amine group in the skin layer will cause the membrane becomes positively charged at low ph. The flux of ES20 membrane is almost twice as compared to the conventional RO membrane because of a thicker top layer. The experiments rig consisted of 7 components (feed and permeate container, pump, pressure gauge, flow meter, pressure regulating valve, test cell) and was set up as

40 24 illustrated in Fig Basically, filtration experiment will be carried out for one set of solution condition, for instance ph, feed concentration and operational pressure which had been determined using MINITAB TM version 14 software. Before the starting and ending of every experiment, Sodium Chloride (NaCL) with a concentration of 500 mg/l was used to examine the efficiency of the membrane. During the experiment, the retentate was circulated back into the feed solution in order to increase the concentration of organic substances in the feed solution. For every experiments, permeate of each sample was collected after 30 minutes. After that, the permeate volume was measured and a portion of it was stored. The permeate flux is then determined based on the volume data measured. The experiment was repeated until the stable permeate was obtained. In this experiment, the study was focused on the polluted synthetic water samples containing endocrine disrupting chemicals (EDCs). The laboratory procedures of preparing the solution are discussed in section 3.3.Two chemical substances below were used to prepare the synthetic polluted water samples in this study: beta Estradiol (C 18 H 24 O 2 ) 2. Bisphenol A d 14 (C 15 H 2 D 14 O 2 ) Overall flux and the percentage of removal of specific substances are the two parameters that used to evaluate the performance of LPRO membrane. Normally, the percentage of removal of the substances is expressed in terms of rejection indirectly. The concentration of permeate and initial feed was obtained using UV spectrophotometer.

41 25 Table 3.1: Specifications of LPROM unit Terms Membrane type Membrane material Membrane configuration Description ES20 Aromatic Polyamide Flat-sheet Effective surface area 60 cm 2 ph 2-10 Charge Negative at ph above 5 Positive at ph below 5 Operating pressure Maximum of 0.90 MPa Operating temperature Maximum of 40 C Manufacturer Nitto Denko Co.

42 26 Figure 3.1 : Schematic Diagram of the experimental set up of LPROM Flow Meter Pressure Regulating Valve Test Cell C-10 T Pump Feed Solution Pressure Gauge Permeate Figure 3.2 : LPROM System in Laboratory

43 27 Figure 3.3 : Schematic Diagram of C10-T module and the Illustration of the Membrane Arrangement.

44 28 Preparation of Experimental rigs. Design of experiment using MINITAB TM version 14 software. Membrane efficiencies test using various samples Study conducted using synthetic samples Performance efficiency test Data collection, comparative and analysis Report Writing Figure 3.4 : Methodology of Performance Investigation Experiment of Low Pressure Reverse Osmosis Membrane.

45 Design of Experiments All the run orders of the experiment were designed with the aid of MINITAB TM Version 14 software. The Box Behnken design was chosen. The experiment for each sample consisted of 15 runs. Three operating variables included in this study were operating pressure, feed concentration, and ph. The range for each variable is shown in Table 3.2. Table 3.2 : Coding System Factor Name Low High A Operating Pressure (psi) B Feed Concentration (mg/l) C ph The ranges of the parameters were chosen based on the suitability of the operation of LPROM process. LPROM can function well in feed ph range of ph 2 to ph 9 and the suitable operating pressure is from 80 psi to 120 psi. Thus, the chosen ph and pressure ranges were considered suitable for the functionality of LPROM in this study. These ranges were entered into the software and the run order in the form of Table 3.3 was generated. The run orders were in randomized condition. The determined run order list was used as the reference for experiments of both samples.

46 30 Table 3.3 : Experimental Run Order for Both Samples (17-beta Estradiol and Bisphenol A). Feed Operating Run Order Concentration Pressure ph (mg/l) (psi)

47 Preparation of Synthetic Polluted Water First of all, a stock solution of synthetic polluted water sample (using 17-beta Estradiol or Bisphenol A) with a concentration of 10 mg/l was prepared. This stock solution will be used to prepare the solution with required concentration by dilution process. The steps of preparing the stock solution are shown as follow:- 1) 10 mg of sample substances (17-beta Estradiol or Bisphenol A) were weight using a digital weighing scale. 2) The samples were placed into a 1000 ml bottle. 3) Distilled water was added into the bottle to produce a 1000 ml solution and the bottle was closed. 4) The solution then was stirred using electronic stirrer to ensure the conformity of the solution. After the stock solution was prepared, dilution process was carried out to prepare the solution with desired concentration. Then either Hydrochloric acid (HCL) or Sodium Hydroxide (NaOH) was used to adjust the ph value of the solution. The volume of stock solution required to achieve the desired concentration can be determined by applying the formula below:- M1 x V1 = M2 x V2 3.1 Where M1 = the concentration of the stock solution (mg/l) M2 = the concentration of the feed solution of each run (mg/l) V1 = volume of the stock solution required (ml) V2 = volume of the feed solution desired (ml)

48 32 Both samples (17-beta Estradiol and Bisphenol A) and Sodium Chloride (NaCL) were prepared using the same methods and utilizing the same equation. 3.4 Experimental Procedures The procedures of the experiment of evaluating the efficiency of LPROM (ES20) were carried out as below: 1. Sodium chloride with concentration of 500mg/L was prepared and it was used to permeate the membrane for 1 hour. 2. The volume of permeates was collected and measured every 20 minutes and the permeation was run for 1 hour. 3. The synthetic polluted water sample was prepared with desired concentration by using synthetic sample of EDCs (17β-estradiol (C 18 H 24 O 2 ) or Bisphenol A (C 15 H 2 D 14 O 2 )) which will be the feed solution. 4. A portion of feed solution was stored after preparation. 5. The permeation of feed solution through the membrane system was run for 2 hours and 30 minutes. 6. The volume of permeates was collected and measured every 30 minutes. 7. A portion of permeate was stored after being measured. 8. The concentration of stored feed solution and permeates were measured by using UV spectrophotometer which the data will be used to calculate the rejection of EDCs after that.

49 Data Analysis Experimental data obtained were calculated using the equations in the section 3.4.1, and respectively. The performance of LPROM is evaluated in term of rejection and flux Flux Flux can be defined as the volume or mass transfers through the membrane surface per unit time. For each run, an average value of permeate flux was obtained from the total samples collected. It can be calculated using the equation below: Average Permeate (ml) 1L F = A X t X 1000 ml 3.2 Where: F = Permeate flux (L/m 2.h) A = Effective area of membrane (60cm2) t = Interval time when each permeate is collected (0.5 hours)

50 Rejection Rejection can be defined as the reduction in percentage of concentration of feed stream relative to permeate stream. It can be calculated using equation below: C f - C p R (%) = C f X 100% 3.3 Where: R = Rejection (%) Cf = Feed concentration (mg/l) Cp = Permeate concentration (mg/l) Recovery Rate Recovery rate is the percentage of feed solution that flows through the membrane as permeate. It can be calculated using equation below: Q p Recovery (%) = Q f X 100% 3.4

51 35 Where: Q p = Flow rate of the permeate (ml/min) Q f = Flow rate of the feed (ml/min) Flow rate of the feed, Q f can be obtained using the corresponding mass balance equation as below: Q f = Q p + Q c 3.5 Where: Q f = Flow rate of the feed (L/min) Q p = Flow rate of the permeate (L/min) Q c = Flow rate of the concentration (L/min)

52 CHAPTER IV RESULTS AND ANALYSIS 4.1 Introduction In this chapter, results and analysis from the laboratory works conducted will be presented. All the discussion will be focused on the efficiencies of LPROM. The efficiency of the LPROM will be evaluated in terms of flux and rejection by varying three operating parameters which include:- 1. Concentration of Feed (C f ). 2. Operating Pressure (P). 3. ph of Feed. The experiments are conducted on two samples which are 17-beta Estradiol and Bisphenol A d 14. The data obtained will be presented in a graphical manner (graphs). In the next few sections, discussions of the results of two experiments which is the determination of removal of 17-beta Estradiol and removal of Bisphenol A will be made. The factors that influence the rejection of the targeted chemicals will be discussed as well. The comparison of the two samples will be displayed in section 4.4.

53 Results and Discussion of 17-beta Estradiol Table 4.1 : Experimental results in terms of flux and rejection of 17-beta Estradiol Feed Operating Run Concentration, Pressure, P ph Flux, F Rejection, R Order C f (mg/l) (psi) (L/m2/hr) (%) Table 4.1 presents the experimental results for the rejection of 17 beta-estradiol using LPROM. Based on the tabulated results, the range of removal percentages of this sample is from 87.20% to 93.56%. The high removal percentages indicate the high efficiency of membrane ES20 in rejecting this chemical substance. The highest rejection is achieved at pressure 120 psi, at ph 6.0 and with concentration 1.00 mg/l (order 2).

54 38 The variation of the pattern of rejection is mainly affected by feed concentration and operating pressure. On the other hand, the range of flux for this case is from L/m2/h to L/m2/h. The highest flux is achieved under pressure 120 psi, at ph 6.0 with concentration 0.10 mg/l (refer to run order 13). From the data obtained, it shows that the operating pressure is the most significant factor affecting the flux. The higher the operating pressure, the flux is observed to be higher as well. Several data will be taken and presented in graphical manner to show the pattern of flux and rejection for 17-beta Estradiol Effects of Operating Pressure 25 Flux (L/m2.h) ph 6, at concentration 0.1 mg/l ph 6, at concentration 1.0 mg/l Pressure (psi) Figure 4.1 : The Effect of Pressure on Flux for 17-beta Estradiol

55 39 Figure 4.1 shows the relationship of operating pressure and the flux of the generation for 17-beta Estradiol. The pattern of the graph indicates that the flux increases with the increase of operating pressure. For instance, the samples with concentration 0.10 mg/l at ph 6.0, under pressure 80 psi to 120 psi show increment in flux from L/m2/h to The result is similar to Ujang and Anderson (1998), Ozaki et al. (2002), Wu et al. (2004) and Ku et al. (2004), which concluded that the higher the operating pressure, the greater the permeate flux will be. LPROM is a pressure driven membrane. That means pressure is applied to force the feed solution which is more concentrated to flow across the membrane to produce permeate which is less concentrated. In other words, the flux will increase when the LPROM is under higher operating pressure. One of the advantages of LPROM compared to the conventional RO membrane is it lower pressure requirement to produce the higher flux. Rejection (%) Pressure (psi) Concentration 1.0 mg/l, at ph 6.0 Concentration 0.55 mg/l, at ph 6.0 Concentration 0.1 mg/l, at ph 6.0 Figure 4.2 : The Effects of Pressure on Rejection Percentage for 17-beta Estradiol Figure 4.2 shows the correlation of pressure and rejection percentage for 17-beta Estradiol. The figure shows that the rejection percentage increases as the operating

56 40 pressure increased. For example, the sample with concentration 0.55 mg/l at ph 6.0, under pressure 80 psi to 120 psi show increment in rejection percentage from % to %. The possible cause of this phenomenon is the decreases of the average pore size of the membrane surface and increases in the preferential of pure water sorption when higher operating pressure is applied. Thus the molecules of the sample will be more difficult to permeate through the membrane under a higher pressure Effects of Concentration 96 Rejection (%) Concentration (mg/l) Pressure 120 psi, at ph 6.0 Pressure 100 psi, at ph 6.0 Pressure 80 psi, at ph 6.0 Figure 4.3 : The effects of Concentration on Rejection Percentage for 17-beta Estradiol Figure 4.3 shows the pattern of rejection percentage under effect of different concentration. The graph indicates that the higher the concentration, the rejection tends to increase as well. From the samples at ph 6.0 and operating pressure is 100 psi, it is

57 41 observed that the increment in term of rejection percentage from % to %. This result is probably due to the effect of concentration polarization. This effect causes reduction in the degree of dissociation of the chemical substances in water, and simultaneously resulted in the formation of more ion-pairs. The size of the ions will be increased due to the formation of ion-pair. Finally, the size increment of the ions will decrease the permeability of ions through the pores of LPROM. This phenomenon is called steric effect. Concentration polarization is more pronounced when the feed solution s concentration is higher. In addition, the effects of intermolecular repulsion will be greater under the condition of higher feed concentration. This effect will increase the rejection rate Effects of ph Rejection (%) ph concentration 0.1 mg/l, at pressure 100 psi concentration 1.0 mg/l, at pressure 100 psi Figure 4.4 : The Effects of ph to Rejection Percentage for 17-beta Estradiol

58 42 Based on the figure 4.4, it was observed that there is an increase of rejection percentage when the pre-determined ph increases. The probable explanation for this phenomenon is the relation of pka value of the chemical substance to its removal rate at different ph. pka value can be termed as the readiness of a substance to dissolve and to produce charged ions at certain ph value. This means that if a substance has a higher pka value, it will dissolve and produce charge at higher ph range. Since the pka value of 17-beta Estradiol is 10.08, it is more likely to dissociate and produce charged ions under the ph value of 9.5 and 6.0 than at ph 2.5. Therefore, the rejection rate is seemed to be increased when the ph is getting higher which is from 2.5 to 9.0. The dissociation of the chemical substance will create charged ions which will be rejected by the membrane with counter ions. Consequently, the higher pka value which means more ions are produced at higher ph range will lead to higher rejection rate at the particular ph range.

59 Results and Discussions of Biphenol A Table 4.2 : Experimental results in term of flux and rejection of Bisphenol A Feed Operating Run Concentration, Pressure, P ph Flux, F Rejection, R Order C f (mg/l) (psi) (L/m2/hr) (%) Table 4.2 presents the experimental results for the rejection of Bisphenol A using LPROM. From the tabulated results displayed, it shows that the range of rejection percentage is from % to % which is slightly higher than the results obtained for 17-beta Estradiol. However, the high removal range indicates the high efficiency of membrane ES20 in removing Bisphenol A.

60 44 The highest rejection percentage is attained at pressure 120 psi, at ph 6.0 and with concentration 1.00 mg/l (refer to run order 2). From the pattern of the results, it can be said that the feed concentration and the operating pressure are the significant factors to rejection. Apart from that, the results displayed that the flux is ranged from 7.13 L/m2/h to L/m2/h. The highest flux value is achieved under pressure 120 psi, at ph 6.0 with concentration 0.10 mg/l (refer to run order 13). The data showcase that the flux increases as the operating pressure applied is increased. This indicates that the flux is significantly affected by pressure, which this pattern is similar to the results obtained for 17-beta Estradiol. The reduction of flux by comparing two run orders which utilized the same feed concentration, operating pressure and ph (run order 8 and 9) is caused by the membrane fouling. Several data will be taken and presented in graphical manners to show the pattern of flux and rejection for 17-beta Estradiol Effects of Operating Pressure 25 Flux (L/m2.h) ph 6, at concentration 0.1 mg/l ph 6, at concentration 1.0 mg/l Pressure (psi) Figure 4.5 : Effects of Pressure on Flux for Bisphenol A

61 45 Figure 4.5 shows how the operating pressure interacts with the flux for Bisphenol A at ph 6, with different concentration. The pattern of the graph showcases that the flux increase when the operating pressure applied is increased. It can be seen from samples with concentration 0.1 mg/l, at ph 6.0 displayed increases in flux from 7.64 L/m2/h to L/m2/h. The conclusion for this result indicates that the operating pressure is the significant factor to flux is similar to the results of 17-beta Estradiol. Thus the explanation is same to what have been written in section However, the overall flux of the Bisphenol A is lower compared to the results of last sample. Rejection (%) Pressure (psi) ph 6, at concentraion 0.1 mg/l ph 6, at concentraion 1.0 mg/l ph 6, at concentraion 0.55 mg/l Figure 4.6 : Effects of Pressure on Rejection Percentage for Bisphenol A Figure 4.6 shows the pattern of rejection percentage under the effect of operating pressure. From the relationship displayed, it can be said that the rejection percentages are getting higher when the pressure increased. For instance, the samples with ph 6.0, at concentration 1.0 mg/l shows increment in rejection from % to % when subjected to pressure ranged from 80 psi to 120 psi. The increase of

62 46 pressure will enhance the increase in preferential of pure water sorption and decrease of membrane pore size. Thus rejection percentage will increase Effects of Concentration 96 Rejection (%) Concentration (mg/l) ph 6, at pressure 80 psi ph 6, at pressure 100 psi ph 6, at pressure 120 psi Figure 4.7 : Effects of Concentration on Rejection Percentage for Bisphenol A Figure 4.7 shows the correlation of how the concentration interacts with rejection percentage. From the graph, the rejection is increasing as concentration is getting higher. As for example, the removal percentages of samples at ph 6.0 which subjected to pressure 100 psi increase from % to %. The displayed result is due to the concentration polarization. This effect will result in decreasing the permeability of ions of substances through membrane when the solution concentration is higher. The other possible cause is the intermolecular repulsion which its effect is greater at higher concentrations.

63 Effects of ph Rejection (%) ph concentration 0.1 mg/l, at pressure 100 psi concentration 1.0 mg/l, at pressure 100 psi Figure 4.8 : Effects of ph on Rejection Percentage for Bisphenol A Figure 4.8 displays the results regarding the relationships of ph to rejection percentages. It shows that when the ph is increasing, the rejection percentage will increase as well. For this phenomenon, pka value of the specified chemical substance is the significant factor to the removal rate at certain ph. The lower the pka value means that the particular substance will dissolve and produce ions at lower ph. The effect is in contrast to the substances with high pka value. The pka value of Bisphenol A is , so it can be concluded that this substance will dissociate and produce charged ions under the ph value of 9.5 and 6.0 than at ph 2.5. This is shown in the graph where for the samples with concentration 0.1 mg/l and at pressure 100 psi, the rejection increases from % to % at ph ranged from 2.5 to 9.5.

64 Comparison on the Rejection of 17-beta Estradiol and Bisphenol A Table 4.3 : Comparison of Rejection Range of Both Samples Sample Rejection (%) Range Bisphenol A beta Estradiol Both experiments are conducted using the same membrane (ES20), same equipments and based on the same run order. From Table 4.3, the range of rejection percentage of Bisphenol A is from % to % while for 17-beta estradiol is from % to %. Both experiments exhibit a high percentage of removal which indicates that this membrane has high effectiveness in rejecting these two substances. However, results of Bisphenol A show a higher rejection percentage which is % compared to 17-beta Estradiol with the highest percentage is This result can be evaluated based on the molecular weight or solubility of both substances. The molecular weight of 17-beta Estradiol is 272 g/mol while the molecular weight of Bisphenol A is 228 g/mol. Nevertheless the solubility of Bisphenol A (1.20 mg/l) is much lower than 17-beta Estradiol (3.60 mg/l). The percentage of differences of both substances in term of solubility is % while the percentage of differences in term molecular weight is only accounted for 16.18%. Thus the solubility will become the governing factor of the rejection in this case. Since the solubility value of Bisphenol is lower than 17-beta Estradiol, this implies that the Bisphenol A is less soluble when solute in particular solvent compared to 17-beta Estradiol. Thus Bisphenol A solution will be more concentrated compared to the solution of 17-beta Estradiol when both samples are solute in the same solvent.

65 49 In this case, molecular polarization will be affecting the rejection rate. Molecular polarization effect is more pronounced in the higher concentration. Hence, the molecules of Bisphenol A will be more difficult to permeate through the membrane compared to molecules of 17-beta Estradiol due to the effects of concentration polarization. As the result of that, the rejection rate of Bisphenol A will be higher than the rejection rate of 17-beta Estradiol.

66 CHAPTER V CONCLUSIONS AND RECOMMENDATIONS 5.1 Conclusion In this chapter, the summary on what have been learned and found from the study will be presented. All the pre-determined objectives listed in chapter 1 have been achieved. Based on the results and analysis of the experiments conducted, several conclusions can be drawn as below: 1) LPROM has high efficiency in rejecting both organic substances with the rejection percentage of Bisphenol A is from % to % while the rejection percentage of 17-beta Estradiol is from % to % which both range are considered as high removal percentage. 2) From the pattern of graphs for both samples displayed, the rejection is influenced by feed concentration as well as operating pressure. 3) The rejection increases when the feed concentration is increased. This phenomenon is probably due to the effect of molecular polarization. The

67 51 rejection increases when higher pressure applied is because of the increases in preferential of pure water sorption and decreases of membrane pore size. 4) Based on the analysis conducted for both samples, the flux increases as the operating pressure applied is increased. The overall flux for Bisphenol A is lower compared to the results of flux for 17-beta Estradiol. 5) The rejection percentage range of Bipshenol A (87.85 % %) is higher than 17-beta estradiol (87.20 % %). This is because of the solubility of Bisphenol A (1.2 mg/l) is lower than 17-beta Estradiol (3.6 mg/l). Solubility is the more influencing factor in affecting the rejection. 5.2 Recommendations Although the study has fulfilled the predetermined objectives, there are certain improvements which can be made to amend the study and obtain a better result. Modification or improvements can be done occasionally and keep abreast to the latest technology available. Statements below are the recommendations for future study: 1) For future study, more organic samples should be used for better investigation of the efficiency of LPROM in term of rejection. 2) In this study, only synthetic samples were used. Therefore, it is encouraged that raw polluted water samples which contain EDCs to be utilized in the future study. Comparison among synthetic and raw polluted water can also be carried out as well.

68 52 3) Membrane should be changed often especially after a few runs to ensure the consistency of the membrane besides preventing the membrane from being affected by the rejected materials accumulated on its surface and to avoid membrane fouling. 4) Several safety measures should be carried out like wearing a protective mask, and always ensure good ventilation in the laboratory. This is because EDCs is a hazardous substances which will cause adverse effects to human health, thus safety is the priority in conducting the experiments to avoid direct contacts with EDCs.

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74 58 Appendix A : Pressure Gauge Appendix B : Membrane ES20 mounted in the crossflow module C-10T

75 59 Appendix C : Magnetic Sterile Appendix D : Pump

76 60 Appendix E : Flow Meter Appendix F : ph Meter