1.0 Abstract

The experiment is carried out to study on four different types of membranes by using Membrane Test Unit model TR14.The experiment is conducted to study characteristics based on 4 different types of membrane which are AFC99(polyamide film),AFC 40 (polyamide film),CA 202 (cellulose acetate) and FP 100 (PVDF),by using Membrane Test Unit model TR14. In plus, this experiment was made to determine the characteristics of 4 types of membranes which different in term of pore size by separation driving force is namely as reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF) and microfiltration (MF) membranes. Besides that, another aim in this experiment is to calculate the composition of solid salt at product. The experiment was run using approximately sodium chloride solution. The pressure supply for each membrane is different at maximum pressure for at which is 18 bar, 12 bar, 10 bar and 8.5 bar for membrane 1, 2, 3, and 4 respectively. For every 1 minute to 10 minutes, the permeate sample is collected and its weight was recorded for each type of membrane use. As the experiment goes, the solution will permeate through the membrane leaving only macromolecules behind. The sample of permeates were taken too made up the weight of permeates per time. The highest amount of permeate during 10 minutes is 8199.7 g that is for membrane 4 and the lowest is about 304.9 g that is membrane 3. The graph of permeate weight versus time then is plotted. From the graph, when the time increase, the permeate weight also increases. For the membrane 4, the line increases gradually. For the membrane 1, 2 and 3 the lines show sloppier with increase in the percentage of composition of salt at product. The experiment was completely and successfully conducted.

2.0 INTRODUCTION

The Membrane Test Unit (Model: TR 14) has been designed to demonstrate the technique of

membrane separations which has become widely held as it provides effective separation without

the usage of heating energy as compared to in distillation process. In this type of membrane, it is

widely used mostly in biotechnology and process industry. Fruit juices are one of the examples

of heat sensitive materials which can be separated or concentrated by virtue of their molecular

weight. The units consists of test module supplied with four different membranes, namely

reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF) and microfiltration (MF)

membranes. With these four different membranes, it allows the students and researchers to carry

out membrane separation process in which being commonly used in the food, dairy,

pharmaceutical and chemical industries. This self-contained unit on a mobile epoxy coated steel

framework, requires only connection to a suitable electricity supply and a normal cold water

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supply to be fully operational. It consists of a feed tank, a product tank, a feed pump, pressure

regulator, water bath and a membrane test module. All parts in contact with the process fluid are

stainless steel, silicon rubber or nitrile rubber. The unit comes with a high pressure feed pump for

delivering the feed to the membrane unit at the desired flow rate and pressure. The retentate line

can be either returned to the feed tank or directly to the drain. Appropriate sensors for flow,

pressure and temperature are installed at strategic locations for process of monitoring and data

acquisitions.

In the experiment that will be conducted, there is a need to study the characteristics of 4 different

types of membranes in TR 14 unit which are:

Membrane 1: AFC 99 (polyamide film)

Membrane 2: AFC 40 (polyamide film)

Membrane 3: CA 202 (cellulose acetate)

Membrane 4: FP 100 (PVDF)

The AFC 99 is rated with 99% NaCl rejection at maximum pressure and temperature which is 64

bar and 80 ℃ whereas the AFC 40 has 60% of CaCl2 rejection at 60 bar and 60℃. Both of the

membranes are being used in the operation of reverse osmosis. Meanwhile, the CA 202 is rated

with apparent retention of 2000 MWCO and the FP 100 is 100000 MWCO. These two

membranes are used in the process of ultrafiltration in which CA 202 operated at 25 bars and 30

℃ whereas the FP 100 operates at 10 bars and 80℃. There are few advantages of cross flow

membranes separations. One of the advantages is the concentrates remain in a mobile from

suitable for further processing. Besides that, it also allows the solutes to fractionate at different

sizes. Other than that, it also be able to prevent solid buildup on the membrane surfaces so that

higher overall liquid removal rate is achieved and solute content of the concentrate may be

varied over a wide range.

3.0 OBJECTIVES

The experiment is conducted in order:

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To study the characteristics of membrane by performing a characteristic study on 4

different types of membranes.

To calculate the composition of solid salt at product.

4.0 THEORY

Membrane separation is a process which the membrane acts as semipermeable barrier and

separation process occurs by the membrane controlling the movement rate of various molecules

between either two liquid phases, two gas phases, or for both liquid and gas phases. These two

fluids are usually miscible and the membrane barrier prevents actual, ordinary hydrodynamic

flow. Membranes commonly consist of a porous support layer with a thin dense layer on top that

forms the actual membrane. Membrane filtration can be a very efficient and economical way of

separating components that are suspended or dissolved in a liquid.

The properties determining the membrane performances are high selectivity and fluxes, good

thermal stability, chemical and mechanical and cost effective and good compatibility with the

operating environment. The membranes are commonly used in the production of potable water

and separation of industrial gases, and can also be used in filtration of particulate matter from

liquid suspension, air, industrial flue gas and the dehydration of ethanol azeotropes. For more

specialized applications, include the ion separation in electrochemical processes, blood dialysis

and urine dialysis, artificial lungs, and controlled release of therapeutic drugs.

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Figure 4-1 Types of Membrane filtration processes based on membrane pore sizes.

Membrane processes can be classified into porous membrane and non-porous membrane. Porous

membrane divided into five categories which are gas diffusion, microfiltration (MF),

ultrafiltration (UF), reverse osmosis (RO) and dialysis. For gas diffusion, the diffusion rate

depends on the pore sizes and molecular weights. Next, microfiltration is used to filter suspended

particles, bacteria or large colloids from solution. The pores diameter of the membranes ranges

from 0.1 to 10 µm. While for ultrafiltration, the diameter size of the pores is in the range of 20 to

1000 Å. It is used to filter dissolved macromolecules such as proteins and polymers from

solution. The membrane pores diameters of reverse osmosis membrane are in the range of 5 to

20 Å which are within the thermal motion of the polymer chains.

While for the non-porous (tight) membrane, the permeants are adsorbed into the membrane

material under the influence such as thermodynamics potential and the driving force exerted. The

examples of the driving forces are gradient of vapour pressure, temperature gradient, pressure,

concentration gradient and gradient in electrical potential electro dialysis. The advantages of

membrane processes are the membrane does not require any phase change and this can resulted

in low energy requirement. Next, the membrane processes are able to recover minor and valuable

components without substantial energy costs. Furthermore, the selectivity of the membrane is

higher compared to the volatility selectivity in distillation process.

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5.0 APPARATUS AND MATERIALS

TR 14 Model (Membrane Test Unit), Digital Weighing Balance, Jars, Stopwatch, 20 L Of Tap

Water, Sodium Chloride Solution, Water, Polyamide Film, Cellulose Acetate, PVDF.

6.0 PROCEDURES

General Start-Up Procedures:

1. Ensure all valves are initially closed.

2. A sodium chloride solution was prepared by adding 100 gram of sodium chloride into

20L of water.

3. The feed tank was filled up with salt solution prepared in step 2. The feed shall always be

maintained at room temperature.

4. The power was turned on for the control panel. All sensors and indicators are checked for

functioning properly.

5. The thermostat was switched on and make sure the thermo oil level was above the coil

inside thermostat. Thermostat connections are checked so that they are properly fitted.

6. The unit is now ready for experiment

Experimental Procedure:

1. The valves V2, V5, V7, V11 and V15 were opened.

2. The plunger pump (P1) was switched on and the maximum working pressure was

adjusted at the pressure gauge until it reached 20 bars, and valve V5 was slowly closed.

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3. Valve V5 was then opened and the membrane maximum inlet pressure was set to 18 bars

for Membrane 1 by adjusting the retentate control valve (V15).

4. The system was allowed to run for 5 minutes and the samples were started to collect from

permeate port. The samples were recorded every 1 minute for 10 minutes and were

weight by using weighing balance.

5. Step 1 to 5 was repeated for Membrane 2, 3 and 4. Open and close the respective sets of

valves and the membrane maximum inlet pressure was adjusted for every membrane.

Membrane Open Valves

(step 2)

Sampling Valves Retentate

Control Valve

Membrane

maximum inlet

pressure (bar)

1 V2,V5,V7,V11

and V15

Open V19 and

close V11

V15 18

2 V2,V5,V8,V12

and V16

Open V20 and

close V12

V16 18

3 V2,V5,V9,V13

and V17

Open V21 and

close V13

V17 18

4 V2,V5,V10,V14

and V18

Open V22 and

close V14

V18 18

6. Graph of permeate weight versus time were plotted.

General Shut-Down Procedure:

1. The plunger pump was switched off (P2)

2. Valve V2 was closed.

3. Valve V3 and V4 was opened and the liquid in the feed and product tank were drained.

4. The piping was flushed with clean water. V3 and V4 was closed and the feed tank was

fill until it is 90% full.

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5. The system was run with the clean water until the feed tank is nearly empty for cleaning

purpose.

7.0 RESULTS

Table 7.1 : Weight of water collected over time for 4 different membranes

Time (min) Weight of permeates (g)

Membrane 1 Membrane 2 Membrane 3 Membrane 4

1 49.0 130.0 29.8 937.8

2 91.2 225.2 60.2 1748.5

3 134.5 321.6 90.7 2555.3

4 177.7 417.1 120.2 3344.2

5 221.1 514.5 151.7 4141.8

6 264.0 613.2 181.9 4956.0

7 307.8 718.0 212.6 5803.1

8 351.6 822.0 242.9 6606.4

9 395.6 929.1 273.8 7418.1

10 439.1 1034.2 304.9 8199.7

Graph 7.1 : Graph of weight of permeates against time

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0 2 4 6 8 10 120

1000

2000

3000

4000

5000

6000

7000

8000

9000

Chart Title

membrane 1Linear (membrane 1)membrane 2Linear (membrane 2)membrane 3Linear (membrane 3)membrane 4Linear (membrane 4)

TIme (min)

Wei

ght o

f per

mea

tes (

g)

8.0 DISCUSSIONS

Membrane separation process is transport of substances between two fractions with the

help of permeable membranes. Membrane separations are classified by pore size and by

separation driving force. These classifications are microfiltration (MF), ultrafiltration (UF),

nanofiltration (NF) and Reverse Osmosis (RO). This experiment was conducted to study the

characteristic of membrane by performing a characteristic study on different membranes. The

membranes used for this experiment were ;

Membrane 1 : AFC 90 (polyamide film)

Membrane 2 : AFC 40 (polyamide film),

Membrane 3 : CA202 (cellulose acetate)

Membrane 4 : FP 100 (PVDF)

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Based on the results obtained membrane 3 collected the least permeates over 10 minutes

period of time, which is only 304.9 g. On the other hand, membrane 4 collected the most

permeates over the 10 minutes period of time, which is 8199.7g. From the graph plotted,

membrane 1 and membrane 3 shows almost same slope of line. While for membrane 4, the

weight of permeates increases gradually as time passes.

As membrane 3 collected the least permeates, it can be say that membrane 3 was used in the

reverse osmosis process. The result obtained shows that membrane 3 has the smallest pore size

compared to the other 3 membranes. This result was acceptable since that in reverse osmosis

process, the membrane only allows water molecules to pass through it.

On the other hand, membrane 1 and membrane 2 collected 439.1 g and 1034.2 g permeates

respectively. Although both of the membranes are polyamide film, the results shows a large

difference in the weight of permeates, which is 595.1 g. This is may due to the different pore

sizes of both membranes. As membrane 2 collected more permeates, it can be say that membrane

2 has larger pore size compared to membrane 1, thus it allows more molecules to pass through it.

Different from other membranes, membrane 4 shows rapid increase in permeates weight in

the 10 minutes period of time. As the weight of permeates, it can be says that membrane 4 has

the biggest pore size compared to other 3 membranes. It can be concluded that membrane 4 was

used in microfiltration process. In the microfiltration process, more molecules were allowed to

pass through the membrane such as water molecule and macromolecules (protein and enzyme). It

explains the weight of permeates recorded by membrane 4.

9.0 Conclusion

This experiment was a quite success and conclusions can be made. Firstly, based on the theory,

the weight of permeates collected from membrane 1 to 4 can be different due to different

maximum inlet pressure of each membrane. The highest amount of permeate at product is 8199.7

g and the lowest is about 304.9 g. It can be seen that the forth membrane carried the largest value

of weight of the collected. This shows that every membrane will give out the same pattern at the

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outlet however, only the values of the weight were different from each other. Therefore, this

shows that the separation process was the fastest in the forth membrane and the first membrane

was the slowest. From the graph, the permeate weight increases while the time increases. For the

membrane 4, the line increases steadily. For the membrane 1, 2 and 3 the lines show sloppier

with increase in the percentage of composition of salt at product. Therefore, the objectives of this

experiment are successfully achieved.

Characteristics of membrane have been determined throughout this experiment. Directly

could be said that; bigger size of pores, greater rate of mass transfer occurs in the membrane.

Most of the graph that plotted is linearly and directly proportional. Hence, the calculation for

slope of each graph can be determined easily. Thus hypothesis of this experiment is accepted.

10.0 Recommendations

There are several recommendations during conduct this experiment:

Ensure that all membrane whether it can be function properly. The liquid cannot flow

through the pipe membrane when the membrane is blocked. Thus, the sample from

permeates cannot be collected completely and the result will be affected.

During adjusted the pressure value at pressure gauge, the eye of observers should be

placed to the scale of pressure gauge to get an accurate desired pressure values for the

experiment.

11.0 REFERENCES

1. http://www.egr.msu.edu/~hashsham/courses/ene806/docs/Membrane%20Filtration.pdf

2. http://ihome.ust.hk/~kexhu/ceng576/576-04.pdf

3. http://www.separationprocesses.com/Membrane/MT_Chp01c.htm

4. http://www.separationprocesses.com/Membrane/MainSet6.htm

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5. http://www.nitto.com/in/en/products/group/membrane/about/

12.0 APPENDICES

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