Membrane sepration processes

The driving force of the separation process is differences in concentration or pressure between the two sides of the membrane. Membrane separation process is a process where a membrane is used to separate the components in a solution by rejecting unwanted substances and allowing the others to pass through the membrane. Schematic of Membrane separation Membranes are semi-permeable barriers, used to separate two phases (permeate and retentate) on the basis of particle size, electric charge. Membrane Separation Methods Reverse osmosis (RO) : Concentration of solution by removal of water. Nanofiltration (NF) : Concentration of organic components by removal of part of monovalent ions like sodium and chlorine (partial demineralization). Ultrafiltration (UF) : Concentration of large and macromolecules. Microfiltration (MF) : Removal of bacteria, separation of macromolecules. s e i g o l o n h c e t d n a e n a r b m e M f o s e p y T Driven by a pressure gradient, in which the membrane separates the solvent (generally water) from other components of a solution. Applicable for water purification, recovery of sugar from candy, recovery of oil-seed protein, and concentration of dilute solution (fruit and vegetable juices, milk). Particle size range: 5×10−3 μm to 10−4 μm Source: https://www.researchgate.net/publication/334390850_Applications_of_membrane_separation_technology_in_food_industry Ultrafiltration: In ultrafiltration technique, Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. Applicable in dairy industry mainly for two purposes i.e production of protein concentrates from whey and cheese from milk. Particle size range: 0.15 μm to 5×10−2 μm Source: https://www.researchgate.net/publication/334390850_Applications_of_membrane_separation_technology_in_food_industry Nanofiltration: The nano filtration technique is mainly used for the removal of two valued ions and the larger mono-valued ions such as heavy metals. Applicable for pre-concentration of thin juices in the production of sugar from sugarcane and beet, desalting of lactose, production of protein concentrates, the demineralization and de-acidification of whey obtained from ultrafiltration. Particle size range: 5×10−2 μm to 5×10−3 μm Microfiltration Microfiltration (MF) is a pressure-driven separation process, which is widely used in concentrating, purifying or separating macromolecules, colloids and suspended particles from solution. Applicable for clarification of beer and wine i.e. for removal of yeasts, microorganisms, pretreatment of cheese whey, removal of oil droplets and fat globules, wastewater treatment. Particle size range: 0.15 μm to 0.15 μm Advantages Able to recover minor but valuable components from a main stream without substantial energy costs. Very simple flowsheet. Extremely high selectivities. Potentially better for the environment. Source: http://www.separationprocesses.com/Membrane/MT_Chp01 Disadvantages Cannot be easily staged compared to processes such as distillation. Can have chemical incompatibilities with process solutions. Temperature limitation. Can be saddled with major problems of fouling of the membranes.