The membrane system for one of ring worker's commonly used separation technology, especially use in separating and purifying. It is single to is it flow liquid divide into and say that liquid shed two times to enter for to make for membrane to filter, lines of liquid specific material membrane centralized and thick after contracting permeability by half have, the thickness is obviously higher than another a line of liquid flows.
Membrane system have person who dissolve material separate by oneself particle, or from ability it, so membrane system can be applied to the thick contracting or final result of purification from material oneself copy of dissolving etc.. Select the proper membrane for use, can isolate the dissolved matter of the specific size, allow other dissolving materials of kind to ooze and pass the membrane. Because the membrane has reliability and cost-effective, so use separation use of the alternative, in order to increase the getting of the result, but needn't use the garniture, glue to congeals the pharmaceutical, covers the chemical material (pre-coat chemicals) in advance ,etc.. Enter when flowing water water quality change range heavy separately, for quality that filter being for light influence of range, also by one of the advantages that the membrane filters.
Membrane kind
Is it flow liquid characteristic for choose main decisive factor, membrane of kind one of to enter, for example: Solid composition of dissolving etc., person who dissolve molecule of material serious suspending the characteristic and thickness of the material. Enter pH and temperature while flowing also for one of the factors of choosing the membrane kind.
And pursue to learn that goes against to permeate (reverse osmosis, RO) by the attached list Can filter minimum molecule, for water or purification that enter the water use its. Then filter (nanofiltration, NF) in order to endure the rice , is it strain to exceed (ultrafiltration, UF) ,And the last little filtration (mircofiltration, MF) ,Filtration that MF is used in the particle each mainly. Can know from filtration kind of the above these to separate procedure with mainly for size of separating the angstrom of counting (angstroms, 10-10m) To several microns (microns, 10-6m) ,The size of pressure is from 1,000psi of the high-pressure system to low-voltage and systematic 15psi within the membrane.
RO uses the membrane caused closely to filter most dissolving materials such as the organic matter of low molecular weight, candy and saline etc., the infiltration that its systematic pressure must be greater than water or solvent containing dissolving material is pressed, in order to pierce through half membrane completely, so daily to is it deal with if waste water bury field ooze out water or thick to contract orange juice, tea or coffee,etc. to come.
NF is a filtration way to lie between RO and UF, daily getting rid of ores (demineralization) With drawing back and getting rid of the molecular weight in the material of 10000 thick.
UF is industrial to have wide use range, such as dyeing weaving waste water and paper pulp waste water, clarification of or the fruit juice,etc..
MF apply large filtration of size to, daily material make or polymer for pottery (polymeric) ,The use is waste water treatment, food, beverage, medicines and chemical industry,etc..
Appearance of the membrane and material
　The development of the technology of the membrane is mainly two respects, first the way to pack for the membrane, such as the tube type (tubular) , spiral type (spiral) , flat (flat-sheet) And hit the empty fibre type (hollow-fiber) Wait for all kinds of geometry characteristics, another membrane material, membrane material make thing for polymer or pottery often.
It has high thickness to suspend solid viscid liquid that the major advantage of the tube type membrane can be dealt with, and all right chemistry or the mechanical way clear up the membrane. The tube type polymer membrane is usually fitted in the stainless steel or in the plastic model's group. Spiral type its advantage of membrane, in order to load the density high (high packing density) ,Will strain the material and charter covering like the sandwich, because the high cause of loading the density has the higher one and is suitable for filtering the surface area of the membrane, only need to filter (pre-filtration) in advance carefully while using Strain divided by suspend the solid, in order to avoid blocking. China getting empty fibre for empty part contain the conspicuous fibre in every membrane (extruded fibers) High load density membrane, filtering the way can be filtered or filtered inwards from outside outwards inside, can carry on back flush. Though its solid standing degree higher than spiral type to suspending, but use and get on and still often add the filter in advance, in order to protect the membrane. Membrane the pressure takes to be lighter than 30 psi when use incessantly.
At the practice, polymer make spiral membrane at spending high result output demanding on usually; And the polymer tube type membrane is suitable for needing less maintenance to operate, and contain and suspend the high viscid degree of fluids state of the material, its is often cleared up with machinery type. Polymer membrane can use or under the acid state, chemistry for instance, retrieve and discard material decrement on person who corrode. Pottery choice to make membrane restrict membrane environment, range and other factors, thickness of solvent and value of pH that practical application in, so often apply to the filtration and separation of such bigger yardstick materials as UF and MF,etc.. The establishment cost made the membrane of the pottery is higher than the traditional polymer membrane, but it operates life-span longer, so can compensate the higher establishment cost in initial stage.
Purpose according to the prevention and control of pollution, water treatment project,etc. is different, the membrane adopted is different to some extent. In practice application, can make use of the way designed by standard, design the unit of the membrane by way of test at least; Or another the engineer carry on the preliminary assessment in accordance with use of the membrane, operation mode and design criteria (preliminary assessment) And extensive test procedure, in order to determine membrane kind, capacity of the construction equipment, composition operating the cost, expecting to be leached (desired composition of the " permeate" )And the leftovers (retentate) ,etc., so how use membrane separate technology invest prevention and control of pollution, water treatment project and field that material separate effectively, still remain to contribute mental and physical efforts in the environmental protection circle. (strong in Kun yellowly)

　　　　　　　　　Comparison sheet of all kinds of membrane of technology
　　　　　　　　　　　 All kinds of thin model's sketch maps