UF Full Form

Ultrafiltration is the process whereby the water is forced through specially designed filters. This process is widely used for water desalination and wastewater treatment. The process in a high flux(low pressure)  filtration system is different from the process in a low flux (high pressure) filtration system. In the process of ultrafiltration, the main task of the membrane is to separate a feed solution from the concentrate (the permeate), while the reject is the retentate. In this case, the feed is water, and the concentrate is the solution containing more pollutants. The membrane is a barrier between separate areas and fluids. It is usually a flat sheet used to separate a liquid from a gas or a liquid.

In a typical ultrafiltration process, the feed solution is first filtered to remove particulate matter and foreign ions. If the feed solution is a solution that cannot be filtered (if the solution is too concentrated), the process is called ultrafiltration. Usually, the filtration rate is controlled to provide a constant filtrate pressure and, therefore, a constant filtrate flux. In this case, the filtered solution is concentrated by evaporation and the evaporated water is condensed and returned to the feed tank, while the concentrate is discarded.

The main goal of the ultrafiltration process is to separate the colloid (suspended solid matter) from the bulk liquid by passing the fluid through a membrane. As fluid flows through the process, the colloid particles that pass through the membrane are separated from the fluid by the membrane itself. This is due to the difference in molecular mass between the colloid and the fluid. The membrane is generally of a specific molecular weight cutoff, in moles per second.

The Principle Behind Ultrafiltration 

Ultrafiltration principle is based on the size exclusion hypothesis. This theory states that molecules larger than a certain size will not pass through a certain membrane. When the molecules are too big or too small they will not pass through but the molecules in between will pass through due to the random movement of the particles. 

The principle behind ultrafiltration is the same as reverse osmosis. Water is forced through a membrane and the unwanted solutes won’t pass through the membrane. The semi permeable membrane can be a fibre or a sheet. When the osmotic pressure is higher than the applied pressure the water flows through the membrane by being separated from the contaminated solutes until the pressure is equal on both sides of the semi permeable membrane. 

The process of Ultrafiltration partly relies on the Darcy law which claims that the removal of large particles by filtering is possible because the larger particles are less likely to diffuse through the smallest pores at the centre of the membrane.

Components of an Ultrafiltration System

An ultrafilter is a device that is used for filtration, usually to separate suspended particles like bacteria, microorganisms or colloids from a flowing liquid stream with a pore size smaller than the particles in the liquid. 

There are several parts of the ultrafiltration system, the membrane filter is the part that actually filters the fluid.It is made of two layers of synthetic polymers, one layer is hydrophilic and the other is hydrophobic. The two layers are attached to each other with an adhesive, and the two surfaces of the membrane are made to have a pore size that will allow certain components of the solution to pass through but not others.

The semi permeable membrane used in an ultra filtration system is most commonly made from cellophane polymer. 

Uses and Applications of Ultrafiltration

• Ultrafiltration in water filtration is used to remove large particles such as bacteria and other biological matter in water, and is an essential step in both water filtration and purification. Water filtration is the process of removing bacteria, microbes, and other organic contaminants from water for potable use                                    
• Ultrafiltration has various uses that may benefit a variety of industries. For example, ultrafiltration is widely utilised in the pharmaceutical and biotechnology industries. In these applications, ultrafiltration is used to remove bacteria, viruses, and particulate matter in fluids, thereby improving the quality and safety of the products

• In the past, ultrafiltration has been used in a wide range of applications including the bioseparation of proteins and purification of biocatalysts. 

• The use of ultrafiltration is common in the laboratory and in biotechnology. Ultrafiltration filtration is used to remove large molecules from solution and/or to concentrate biomolecules

• Ultrafiltration is used in many biotechnological processes, including virus inactivation, food processing, fractionation of proteins and nucleic acids, and the removal of toxic substances or particles from water and enzyme recovery

 The most important application of Ultrafiltration is in Dialysis

• Ultrafiltration membranes are used in dialysis and renal replacement therapy for treating patients with end-stage renal disease. In dialysis, a patient’s blood is passed through a membrane in a process called diffusion. In the process, water and electrolytes pass through the membrane into the patient’s blood, while waste products, including urea and other molecules, pass through the membrane back into the patient’s urine. This process is repeated several times a day, usually over a period of weeks or months

Conclusion

Ultrafiltration is the process of removing material from a liquid solution which is too large (in molecular size) to pass through a particulate-selective membrane. This membrane is designed to filter out all contaminants larger than a certain size, while allowing the solution to pass completely through. The membrane can be made from a variety of materials and materials can be combined in membrane fabrication depending on the desired application.