Difference between revisions of "Membrane filtration"

Membrane filtration can be carried out by means of two operating modes: dead-end filtration and cross-flow filtration. In dead-end filtration, the feed stream flows perpendicular to the membrane and is forced through the membrane. In consequence, the retained components accumulate on the membrane surface forming a cake layer, resulting in a decrease of the filtration rate due to the additional resistance to filtration of this cake layer. Dead-end operation mode is mostly employed in MF and is commonly used for separation of solid biomass from different feedstocks withing pre-treatment process. In cross-flow filtration (CFF), the feed flows parallel to the membrane surface. The tangential flow allows drag of the accumulated rejected solutes on the surface of the membrane, limiting the thickness of the cake layer and helping to maintain the permeate flow. CFF is widely used for concentration, purification or fractionation of target compounds from liquid streams.

Membrane filtration can be carried out by means of two operating modes: dead-end filtration and cross-flow filtration. In dead-end filtration, the feed stream flows perpendicular to the membrane and is forced through the membrane. In consequence, the retained components accumulate on the membrane surface forming a cake layer, resulting in a decrease of the filtration rate due to the additional resistance to filtration of this cake layer. Dead-end operation mode is mostly employed in MF and is commonly used for separation of solid biomass from different feedstocks withing pre-treatment process. In cross-flow filtration (CFF), the feed flows parallel to the membrane surface. The tangential flow allows drag of the accumulated rejected solutes on the surface of the membrane, limiting the thickness of the cake layer and helping to maintain the permeate flow. CFF is widely used for concentration, purification or fractionation of target compounds from liquid streams.

The membrane module is also a key parameter in the performance of a membrane separation process. The modules are designed with the objective of increasing turbulence on the surface of the membrane to reduce the mass transfer resistance and the concentration effects. The most used modules are plate and frame, spiral, tubular and hollow fibres.  

The membrane module is also a key parameter in the performance of a membrane separation process. The modules are designed with the objective of increasing turbulence on the surface of the membrane to reduce the mass transfer resistance and the concentration effects. The most used modules are plate and frame, spiral, tubular and hollow fibres.