Membrane Experiment

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Separation processes by using the application of membrane have become highly demand in various industries. In this newly separation process , the membrane function as a semi-permeable barrier and the separation process occur by the membrane controlling the rate of movement of various molecules between two liquid phases , two gas phases or a mixture of a gas phase and liquid phase. In industries, many companies have high demand on both quality and quantity of water for production. Membrane process can be used to separate chemical substances in various types and sizes from microscopic to molecular level. The objective of this experiment is to study the characteristic of four different types of membrane. The membranes used in this experiment are polyamide film ( AFC 99 ) as membrane one , polyamide film ( AFC 40 ) as membrane two , cellulose acetate (CA 202 ) as the third membrane and PVDF (FP 100 ) that act as the fourth membrane. In order to identify the characteristic of all four membranes, experimental procedures should be done. The variable for this experiment is the membrane maximum inlet pressure, where different membrane maximum inlet pressure is set for each of the membrane. Then after the experiment has run for specific time, an amount of sample called permeates which is actually the water is taken from every membrane. The weight for the permeate for all four membrane are recorded and compared in order to study the characteristic of the membrane. In addition, this experiment has shown that the pressure gradient will give some effect to the membrane. The pressure gradient must be suitable with the pore size of each membrane because the loss of permeate flow is an undesirable condition for this experiment. After finishing the experiment, the volume of water collected increases according to the sequence of reverse osmosis, nanofiltration, microfiltration and ultrafitration.

Membrane separation is a type of modern technology that is selectively separates, clarifies and fractionates materials from a solution in a wide variety of industries. This technology has been used over the past decade because it has many advantages that give benefits human as users. Membrane can be illustrates as a wall that separates two different segments, allowing fluid and some small particles or chemicals to pass through it via pores on the membrane itself. But, in this experiment, the membranes used are come up with hollow tube in shape. The sodium chloride and water solution flows from the feed tank by applied pressure to pass through the respective membrane. Some of the sodium chloride caught in the membrane while the others pass through the pore.

Membrane can be classified into four major categories which are Microfiltration, Ultrafiltration, Nanofiltration and Reverse Osmosis. Some other categories are gas diffusion in porous solid, liquid permeation or dialysis and gel permeation chromatography. The classification is based on the molecular size of particles that can pass through the membrane or by the separation driving force.

Refer to K. L. Tung (2010), microfiltration (MF) is the oldest separation technique among the pressure-driven membrane separation processes today. These membranes are absolute filters typically rated the 0.1 to 3.0 micron range. For ultrafiltration, the pore size is range between 0.01 to 0.03 microns. It is often used to remove high molecular-weight substances, colloidal materials, and organic and inorganic polymeric molecules. Nanofiltration membrane pore size is between 0.001 to 0.0001 microns that can typically removes 50% to 90%, depending on the material and manufacture of the membrane. The pore size of reverse osmosis membrane is less than 0.0001 microns and hence, this is the best membrane in term of percent of rejection.

In this experiment, there are four types of membrane...
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