what is meant by ultrafitration?

Answer 1

It should be ultrafiltration and also known as nanofiltration and the details are shown below.

Nanofiltration is a pressure driven separation process. The filtration process takes place on a selective separation layer formed by an organic semipermeable membrane. The driving force of the separation process is the pressure difference between the feed (retentate) and the filtrate (permeate) side at the separation layer of the membrane. However, because of its selectivity, one or several components of a dissolved mixture are retained by the membrane despite the driving force, while water and substances with a molecular weight < 200 D are able to permeate the semipermeable separation layer. Because nanofiltration membranes also have a selectivity for the charge of the dissolved components, monovalent ions will pass the membrane and divalent and multivalent ions will be rejected.
VR

Answer 2

Ultrafiltration (UF) is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. This separation process is used in industry and research for purifying and concentrating macromolecular (10^3 - 10^6 Da) solutions, especially protein solutions. Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains.
Industries such as chemical and pharmaceutical processing, food and beverage processing, and waste water treatment, employ UF in order to recycle flow or add value to later products. UF's main attraction is its ability to purify, separate, and concentrate target macromolecules in continuous systems. UF does this by pressurizing the solution flow, which is tangential to the surface of the supported membrane (cross-flow filtration). The solvent and other dissolved components that pass through the membrane are known as permeate. The components that do not pass through are known as retentate. Depending on the Molecular Weight Cut Off (MWCO) of the membrane used, macromolecules may be purified, separated, or concentrated in either fraction. Currently, the study of UF processing occurs mainly in laboratory setups because it is very prone to membrane fouling caused by increased solute concentration at the membrane surface (either by macromolecular adsorption to internal pore structure of membrane, or aggregation of protein deposit on surface of membrane), which leads to concentration polarization (CP). CP is the major culprit in decreasing permeate flux. Ultrafiltration is used in reverse osmosis processes in many Middle Eastern countries to produce fresh water as there is little fresh water available in those areas.

Answer 3

Ultrafiltration is a process where the ultrafilter used is generally rated to have pores capable of retaining molecules between a molecular weight of 1,000 to 1,000,000.

The filters are made so, for example, molecules with molecular weight of 100,000 will be retained (industry speak: molecular weight cutoff [MWCO] is 100K) allowing the separation of molecules of 130K from molecules, say, below 50 K.

Nanofiltration is something else and should not be mixed here.

Answer 4

this is a method of filtering out impurities out of colloidal substances.
the sample is taken in a cellophane bag and it is kept in a
stream of fast flowing water and impurities having greater
dimensions than that of colloidal particles are carried away by water.if this is done under the aid of electricity ,the process become faster and this is called ultrafilteration

Answer 5

Ultrafiltration (UF) is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. This separation process is used in industry and research for purifying and concentrating macromolecular (10^3 - 10^6 Da) solutions, especially protein solutions. Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains.

Industries such as chemical and pharmaceutical processing, food and beverage processing, and waste water treatment, employ UF in order to recycle flow or add value to later products. UF's main attraction is its ability to purify, separate, and concentrate target macromolecules in continuous systems. UF does this by pressurizing the solution flow, which is tangential to the surface of the supported membrane (cross-flow filtration). The solvent and other dissolved components that pass through the membrane are known as permeate. The components that do not pass through are known as retentate. Depending on the Molecular Weight Cut Off (MWCO) of the membrane used, macromolecules may be purified, separated, or concentrated in either fraction. Currently, the study of UF processing occurs mainly in laboratory setups because it is very prone to membrane fouling caused by increased solute concentration at the membrane surface (either by macromolecular adsorption to internal pore structure of membrane, or aggregation of protein deposit on surface of membrane), which leads to concentration polarization (CP). CP is the major culprit in decreasing permeate flux. Ultrafiltration is used in reverse osmosis processes in many Middle Eastern countries to produce fresh water as there is little fresh water available in those areas.

Ultrafiltration (UF) is a pressure-driven barrier to suspended solids, bacteria, viruses, endotoxins and other pathogens to produce water with very high purity and low silt density. It serves as a pretreatment for surface water, seawater, and biologically treated municipal effluent before reverse osmosis and other membrane systems. GE ultrafiltration membranes are supplied with molecular weight cutoffs (MWCO) from 13,000 to 200,000 Daltons and achieve:

Greater than 6-Log (99.9999%) removal of Cryptosporidium and Giardia lamblia
Highest certified removal, 4-Log (99.99%), of viruses and pathogens


Ultrafiltration is also used in industry to separate suspended solids from solution. Industrial applications include power generation, food and beverage processing, pharmaceutical production, biotechnology, and semiconductor manufacturing.


for more pl. visit:
http://en.wikipedia.org/wiki/Ultrafiltration
http://www.gewater.com/library/tp/835_Ultrafiltration_.jsp

Answer 6

open ur 10th class book & u'll come 2 know.