Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
  • B01D67/0002—Organic membrane manufacture
  • B01D67/0004—Organic membrane manufacture by agglomeration of particles
  • B01D67/00046—Organic membrane manufacture by agglomeration of particles by deposition by filtration through a support or base layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/027—Nanofiltration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/14—Dynamic membranes
  • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
  • B01D69/148—Organic/inorganic mixed matrix membranes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/24—Rubbers

Definitions

• the invention relates to a nanofiltration membrane, a process for the preparation of this membrane and their use.
• membranes are used for the separation of solid-liquid mixtures and liquids. In terms of environmental technology, these are also used in the purification of wastewater and the production of drinking water.
• membrane separation processes are known from the prior art. These include microfiltration, ultrafiltration and nanofiltration, as well as reverse osmosis. These methods are to be assigned to the mechanical separation processes.
• the separation mechanisms are caused by different membrane structures. They separate by means of membrane pores whose diameters are smaller than those of the particles to be separated.
• Known processes for the treatment of liquids under pressure are microfiltration, ultrafiltration and nanofiltration.
• the pore sizes of the nano-, ultra- and microfiltration membranes are about 0.001 ⁇ m to 10.0 ⁇ m.
• the retention R with respect to a substance is usually used.
• the highest possible flow is sought while at the same time at least equivalent retention of the membrane. This can e.g. be achieved by a hydrophilization of the membrane material.
• Hydrophilization in addition to the corresponding chemical modification of the actual polymer material, also includes the addition of hydrophilic additives which are incorporated as uniformly as possible into the polymer matrix during membrane production.
• BWRO Brackish Water Reverse Osmosis Membrane
• SWRO Seawater Reverse Osmosis Membrane
• membranes comprising a support membrane and a release active polymer coating with inorganic and organic particles for use as a separation membrane in batteries are known from US 2010/206804.
• CN 101824118 A discloses release-active polymer coatings.
• Further composite membranes are known from EP 1254697 and EP 071 1199 Bl. A disadvantage of these membranes is further that there is no sufficient stability of the membranes under extreme pH values and that a satisfactory flow can not be achieved.
• one major problem with all known membrane synthesis methods is to control the adjustment of the pore size and the pore shape of the separation-active layer exactly and uniformly and thus to achieve a very narrow pore size distribution.
• Polymeric membranes of a wide variety of polymers are available at relatively low cost for wide pH ranges and many applications, but are mostly not resistant to organic solvents as well as very high and / or very low pHs. Also, a permanent temperature resistance at over 80 ° C is rarely given. While there are many approaches to improve these properties on polymer membranes, one of the above is often one of the above.
• Polymeric materials is the poor resistance to organic solvents or oils and the plasticizing effect of the oils on the polymers. As a result, the separation capacity of the membranes is impaired.
• Membrane technology plays an important role in the purification of liquid mixtures.
• dilute solutions are usually concentrated and separated organic solvents, water or salt solutions. Here are either recyclables or ⁇
• Pollutants obtained in more concentrated and possibly lower-salt solutions which can be cost-effective subsequent storage, transport, disposal and processing.
• wastewater treatment it is the goal of the membrane treatment to recover the largest part of the volume as permeate in a not or only slightly loaded form.
• the concentrated retentate can with less effort with respect to still existing
• Reclaimed recyclables or disposed of in this concentrated form for example by incineration, cheaper.
• nanofiltration membranes are composite membranes prepared by interfacial condensation, such as described in US 5,049,167.
• these known membranes can be prepared only very expensive and only in compliance with costly safety measures, since as starting materials z.
• carcinogenic diamines and highly reactive acrylic chlorides are used.
• Such membranes can be configured in many ways, for example as flat film modules, cassette modules, spiral wound modules or hollow fiber modules.
• Another object of the invention is also to provide a method by which it is possible to produce defined pore sizes for the respective membranes. It is known in the art that polymer particles on a porous substrate having a broader pore size distribution can be deposited to obtain a composite membrane having a narrower pore size distribution. The voids between the particles form pores with which separation from a liquid can be performed.
• the composite membranes obtained in this way can be used, for example, as ultrafiltration and micro-membranes. filtration membranes are used.
• a nanofiltration membrane of the aforementioned type wherein the surface of the support membrane produced by emulsion rubbery polymer particles having a mean particle diameter ⁇ 70 nm, preferably between 30 to 65 nm, more preferably between 40 to 50 nm and with nanoparticles at least an oxide selected from Fe 2 O 3 , FesO i, Fe (OOH), TiO 2 , and SiO 2 , and both rubbery polymer particles and oxide nanoparticles form the release active layer and the rubbery polymers are prepared from monomers; which contain as functional group at least one conjugated diene. It is here to distinguish between the filtration property of a membrane, characterized for example by the cut-off, and the structure of the filtration membrane.
• Separation, separation properties, separation behavior are used as synonyms.
• the separation effect is with the help of 0. g. Cut-off defined.
• Polymer particles also nanoparticles.
• emulsion polymerized rubbery polymer particles having an average particle diameter ⁇ 70 nm, preferably between 30 to 65 nm, more preferably between 40 and 50 nm, offers numerous advantages over other polymer particles, since the chemical and physical properties of the rubbery polymer particles, such as
• Particle size, particle morphology, swelling behavior, hardness, dimensional stability, and surface energy can be adjusted. This is done on the one hand by the manufacturing process, in particular by the polymerization process, as well as by the selection of suitable base monomers and on the other hand by the selection of suitable functional groups whose concentration and settlement area in the polymer particles can be selectively adjusted or tailored within wide limits.
• the release-active layer is thus the rubber-like polymer particles produced by emulsion polymerization with a mean particle diameter ⁇ 70 nm, preferably between 30 to 65 nm, more preferably between 40 to 50 nm, layer also referred to as polymer layer, the nanofiltration membrane according to the invention, which moreover at least one Contains oxide in the form of nanoparticles.
• Emulsion polymerization is understood to mean, in particular, a process which is known per se, in which water is usually used as the reaction medium, in which the monomers used are in the presence or absence of emulsifiers and free-radical-forming substances with formation r
• Particles of size less than 500 nm are generally not accessible by suspension or dispersion polymerization and therefore these particles are generally unsuitable for the purposes of the present invention.
• the flow through nanofiltration membranes can be considerably increased if the surface of the supporting membrane of a nanofiltration membrane is coated with rubbery polymer particles having an average particle diameter of ⁇ 70 nm and with nanoparticles of at least one oxide produced by emulsion polymerization and both rubber-like polymer particles and oxide particles. Nanoparticles form the separation-active layer.
• the choice of monomers sets the glass transition temperature and the glass transition width of the rubbery polymer particles.
• the determination of the glass transition temperature (Tg) and the width of the glass transition (ATg) of the rubbery polymer particles is carried out by differential scanning calorimetry (DSC), preferably as described below.
• DSC differential scanning calorimetry
• two cooling / heating cycles are carried out for the determination of Tg and ATg.
• Tg and ATg are determined in the second heating cycle.
• approximately 10-12 mg of the selected polymer particle is placed in a Perkin-Elmer DSC sample container (standard aluminum pan).
• the first DSC cycle is carried out by first cooling the sample to -100 ° C with liquid nitrogen and then heating to + 150 ° C at a rate of 20K / min.
• the second DSC cycle is started by immediately cooling the sample as soon as a sample temperature of + 150 ° C is reached.
• the heating rate in the second cycle is again 20K / min.
• Tg and ATg are determined graphically on the DSC curve of the second heating process.
• three straight lines are applied to the DSC curve.
• the 1st straight line is applied to the curve part of the DSC curve below Tg, the 2nd straight line to the curve branch with inflection point passing through Tg and the 3rd straight line to the curve branch of the DSC curve above Tg. In this way, three straight lines with two intersections are obtained. Both intersections are each characterized by a characteristic temperature.
• the glass transition temperature Tg is obtained as the mean value of these two temperatures and the width of the glass transition ATg is obtained from the difference between the two temperatures.
• the rubbery polymer particles have a glass transition temperature (Tg) of -85 ° C to 150 ° C, preferably -75 ° C to 110 ° C, more preferably -70 ° C to 90 ° C on.
• the width of the glass transition is preferably greater than 5 ° C., more preferably greater than 10 ° C., in the case of the rubbery polymer particles used according to the invention.
• Rubbery polymer particles according to the invention are prepared from monomers which contain at least one conjugated diene as the functional group.
• (meth) denotes both the respective acrylic compound and the respective methacrylic compound.
• from 1 to 80% by weight, preferably from 1 to 60% by weight, more preferably from 1 to 40% by weight, even more preferably from 1 to 30% by weight, of the stated monomers are used for the preparation of the rubbery polymer particles.
• the rubbery polymer particles may be crosslinked or uncrosslinked.
• the rubbery polymer particles may in particular be those based on homopolymers or random copolymers.
• homopolymers and random copolymers are known to the person skilled in the art and are explained, for example, by Vollmert, Polymer Chemistry, Springer 1973. The following may be used in particular as the polymer base of the rubbery, crosslinked or uncrosslinked rubbery polymer particles containing functional groups:
• BR polybutadiene
• SBR styrene-butadiene random copolymers having styrene contents of 1-60, preferably 5-50 wt%
• FKM fluororubber
• ACM acrylate rubber
• NBR polybutadiene-acrylonitrile copolymers having acrylonitrile contents of 5-60, preferably 10-60, weight percent,
• EVM ethylene / vinyl acetate copolymers.
• rubbery polymer particles are thermoplastic and those based on methacrylates, in particular methyl methacrylate, styrene, alpha-methylstyrene and acrylonitrile.
• the rubbery polymer particles preferably have an approximately spherical geometry.
• the rubbery polymer particles used according to the invention have an average particle diameter of less than 70 nm, preferably between 30 and 65 nm, particularly preferably between 40 and 50 nm.
• the average particle diameter is determined by ultracentrifugation with the aqueous latex of the rubbery polymer particles from the emulsion polymerization.
• the method gives a mean value for the particle diameter taking into account any agglomerates. (HG Müller (1996) Colloid Polymer Science 267: 1113-1116 and W. Scholtan, H. Lange (1972) Kolloid-Z and Z. Polymere 250: 782).
• Ultracentrifugation has the advantage of characterizing the total particle size distribution and calculating various means such as number average and weight average from the distribution curve.
• the average diameter data used according to the invention relate to the weight average. Diameter data such as dio, d 5 o and dgo can be used.
• the rubbery polymer particles are prepared by emulsion polymerization, wherein the particle size is adjusted in a wide diameter range by varying the starting materials and emulsifier concentration, initiator concentration, liquor ratio of organic to aqueous phase, ratio of hydrophilic to hydrophobic monomers, amount of crosslinking monomer, polymerization temperature, etc. After polymerization, the latices are treated by vacuum distillation or by stripping with superheated steam to separate volatile components, especially unreacted monomers.
• Polymer particles are at least partially crosslinked in a preferred embodiment.
• Crosslinking of the rubbery polymer particles may be achieved directly during emulsion polymerization, such as by copolymerization with crosslinking multifunctional compounds or by subsequent crosslinking as described below. Direct crosslinking during emulsion polymerization is preferred.
• 2- to 4-valent C 2 to C 10 alcohols such as ethylene glycol, 1,2-propanediol, butanediol, hexanediol, polyethylene glycol having from 2 to 20, preferably 2 to 8 oxyethylene units, neopentyl glycol,
• the crosslinking during the emulsion polymerization can also be carried out by continuing the polymerization up to high conversions or in the monomer feed process by polymerization with high internal conversions. Another possibility is to carry out the emulsion polymerization in the absence of regulators.
• Suitable crosslinking chemicals in this case are organic peroxides, in particular dicumyl peroxide, t-butylcumyl peroxide, bis (t-butyl-peroxy-isopropyl) benzene, di-t-butyl peroxide, 2,5-ditmethylhexane-2,5-dihydroperoxide, 2,5-dimethylhexine-3,2,5-dihydroperoxide, dibenzoyl peroxide, bis (2,4-dichlorobenzoyl) peroxide, t-butyl perbenzoate and organic azo compounds, in particular azo-bis-isobutyronitrile and azo-bis-cyclohexanenitrile and di- and Polymercaptoeducationen, in particular dimercaptoethane, 1,6-dimercaptohexane, 1,3,5-trimercaptotriazine and mercapto-terminated polysulfide rubbers, in particular mercap
• the optimum temperature for carrying out the postcrosslinking is naturally dependent on the reactivity of the crosslinker and can be carried out at temperatures from room temperature - about 23 ° C - to about 180 ° C optionally under elevated pressure (see Houben- Weyl, Methods of the organic Chemistry, 4th Edition, Volume 14/2, page 848).
• Particularly preferred crosslinking agents are peroxides.
• degree of crosslinking is defined by the swelling index [dimensionless] and the gel content [wt%].
• the rubber-like polymer particles which are at least partially crosslinked in a preferred embodiment according to the invention therefore have insoluble fractions (gel content) in toluene at 23 ° C. of at least about 50% by weight, preferably at least about 80% by weight, particularly preferably 90% by weight. more preferably at least about 98% by weight.
• the insoluble in toluene content is determined in toluene at 23 ° C.
• 250 mg of the rubbery polymer particles are swollen in 25 ml of toluene for 24 hours with shaking at 23 ° C.
• the insoluble fraction is separated and dried.
• the gel content results from the quotient of the dried residue and the weight and is given in percent by weight.
• the rubber-like polymer particles which are at least partially crosslinked in a preferred embodiment therefore also have a swelling index of less than about 80, more preferably less than 60, even more preferably less than 40, in toluene at 23 ° C.
• the swelling indices of the rubbery polymer particles (Qi) are between 1 and 20, more preferably between 1 and 10.
• the swelling index is calculated from the weight of the solvent-containing rubbery polymer particles swollen in toluene at 23 ° C for 24 hours (after centrifugation at 20,000 rpm) and calculated on the weight of the dry rubbery polymer particles:
• Qi wet weight of the polymer particles / dry weight of the rubbery polymer particles.
• the release-active layer preferably consists of at least one monolayer of the rubber-like polymer particles to be produced by emulsion polymerization and of at least one oxide likewise in the form of nanoparticles, ie at least one oxide whose particle size is typically in the range from 1 to 100 nanometers.
• Nanoparticulate oxides preferred according to the invention are those of the elements Al, Si, Ca, Fe, Mn, Cr, Ti, V, Zn, Zr, Sn. "
• nanoparticulate oxides of the elements Fe, Al, Zn, Ti, Zr or Si are particularly preferred.
• the nanoparticulate oxides are randomly distributed in the separating active layer.
• the content of nanoparticulate oxides in the separation-active layer is preferably 0.1 to 75% by weight, more preferably 0.5 to 60% by weight, most preferably 1 to 50% by weight.
• the application / incorporation of the nanoparticulate oxides on the support membrane or in the separation-active layer is preferably carried out by the mixing of oxides with the suspension of the rubbery polymer particles and the subsequent application of the mixture as a layer on a porous support membrane.
• ZnO, Al 2 O 3 and ZrO 2 nanoparticles which are suitable according to the invention are obtainable, for example, from Sigma-Aldrich (St. Louis, MO). Nanoparticles of S1O 2 are available as Aerosil® 380 from Evonik Industries AG, Dusseldorf. Nanoparticulate, Ti0 2 is available from Kronos Titan (Leverkusen).
• the supporting membrane of the nanofluid membrane consists of an inorganic or organic material.
• the porous support membrane is chemically and / or mechanically stable. It should be pH-stable and also in organic solvents, such as aldehydes, ketones, monohydric and polyhydric alcohols, benzene derivatives, halogenated hydrocarbons, ethers, esters, carboxylic acids, cyclic hydrocarbons, amines, amides, lactams, lactones, sulfoxides, Alkanes, alkenes.
• organic solvents such as aldehydes, ketones, monohydric and polyhydric alcohols, benzene derivatives, halogenated hydrocarbons, ethers, esters, carboxylic acids, cyclic hydrocarbons, amines, amides, lactams, lactones, sulfoxides, Alkanes, alkenes.
• a support membrane is selected which is chemically stable in the following solvents: acetone, toluene, benzene, water, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, N-ethylpyrrolidone, pyridine, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentane , Hexane, heptane, octane, nonane, decane, methyl ethyl ketone, diethyl ether, dichloromethane, tetrachloroethane, carbon tetrachloride, methyl tert-butyl ether,
• Chlorobenzene Chlorobenzene, dichlorobenzene, trichlorobenzene, nitrobenzene, ethyl acetate, cyclohexane.
• the nanofluid membrane according to the invention is stable, in particular also in the pH range of 10 to 16 and / or in the pH range of 2 to 4.
• the support membrane consists of a material which is thermally stable both at room temperature and in typical application process temperatures.
• an inorganic, permeable supporting membrane preferably micro-glass fiber fleeces, metal fleeces, dense glass fiber fabric or metal fabric, but also ceramic or carbon fiber nonwovens or fabrics are used.
• ceramic or carbon fiber nonwovens or fabrics are used as support membranes.
• Composite materials can be used, in particular inorganic support materials of an oxide selected from Al 2 O 3 , titanium oxide, zirconium oxide or silicon oxide.
• the inorganic support membrane comprises a material selected from ceramic, SiC, S1 3 N 4 , carbon, glass, metal or semimetal.
• organic polymer materials having sufficient chemical and thermal resistance can be used as the supporting membrane, particularly polyimide, polytetrafluoroethylene, polyvinylidene fluoride, polyetherimide, polyetherketone, polyetheretherketone, polyethersulfone, polysulfone, polybenzimidazole, polyamide.
• the porous support membranes have a pore size of less than 500 nm. With particular preference, they have a pore size of less than 100 nm and very particularly preferably less than 50 nm.
• the pore size of the porous support membrane is particularly preferably smaller than the mean particle diameter of the polymer particles or of the nanoparticulate oxides.
• the thickness of the support membrane 20 to 200 ⁇ more preferably from 40 to 150 ⁇ , most preferably from 50 to 140 ⁇ .
• the rubbery polymer particles prepared by emulsion polymerization are at least partially functionalized by the addition of polyfunctional monomers in the polymerization.
• Polyols and maleic acid, fumaric acid, and / or itaconic acid are examples of polyols and maleic acid, fumaric acid, and / or itaconic acid.
• the separation-active layer of the nanofiltration membrane according to the invention preferably has at least one monolayer of the mixture of nanoparticulate oxides and polymer particles having the average particle diameter ⁇ 70 nm, preferably between 30 and 65 nm, particularly preferably between 40 and 50 nm. ⁇
• a preferred embodiment of the nanofluid membrane according to the invention has a separation-active layer with a thickness of from 0.1 to 20 ⁇ m, with several layers of the polymer particles lying on top of one another.
• the thickness of the separation-active layer is at most as thick as the support membrane.
• Another invention is the production process of the nanofiltration membrane according to the invention, wherein a dispersion (latex) of rubbery polymer particles prepared by emulsion polymerization is applied to the support membrane together with at least one nanoparticulate oxide and a polymer layer (release active layer) is formed on the support membrane.
• a dispersion (latex) of rubbery polymer particles prepared by emulsion polymerization is applied to the support membrane together with at least one nanoparticulate oxide and a polymer layer (release active layer) is formed on the support membrane.
• the dispersion of rubbery polymer particles prepared by emulsion polymerization is largely monodisperse, i. H. According to the method of dynamic light scattering, 95.4% of the polymer particles are in a size class with a deviation of ⁇ 7 nm.
• the nanoparticulate oxides are preferably incorporated by addition and mixing in the polymer suspension.
• the process is carried out continuously.
• the aqueous dispersion preferably comprises rubbery polymer particles having a mean particle diameter ⁇ 70 nm, preferably between 30 and 65 nm, particularly preferably between 40 and 50 nm, the dry rubber content after the polymerization being at least 20%, preferably at least 25%, more preferably at least
• the concentration of latices to a dry rubber content of not more than 65% based on the total volume of the polymer is conceivable for the production of the membrane as well as a dilution of up to 1%.
• the dry rubber content is determined as follows: The dry rubber content is determined with a halogen moisture meter, such as the Mettler Toledo Halogen Moisture Analyzer HG63. Here, a latex is dried at a temperature of 140 ° C and weighed continuously. The measurement is considered complete when the weight loss is less than 1 mg / 50 sec.
• the dry rubber content after the polymerization is preferably at most 65%, based on the total volume of the polymer.
• the latex with the rubbery polymer particles is applied to the support membrane by means of a nozzle.
• the nanofiltration membrane formed in this way is dried.
• the nanofiltration membrane formed in this way can additionally be crosslinked, whereby the rubber-like polymer particles with one another and / or with the
• Supporting membrane to be connected.
• chemical (covalent and / or ionic) as well as physical types of crosslinking are induced by electromagnetic (e.g., UV), thermal, and / or radioactive radiation. All conventional crosslinking aids can be used. This further reduces the pore size and modifies the filtration properties.
• Another invention is the use of rubbery polymer particles prepared by emulsion polymerization with average particle diameters ⁇ 70 nm, preferably between 30 to 65 nm, more preferably between 40 to 50 nm together with at least one nanoparticulate oxide for producing a nanofiltration membrane.
• rubbery polymer particles prepared by emulsion polymerization with average particle diameters ⁇ 70 nm, preferably between 30 to 65 nm, more preferably between 40 to 50 nm together with at least one nanoparticulate oxide for producing a nanofiltration membrane.
• Invention is the use of the nanofiltration membrane for the food industry, for the chemical industry and for the biochemical industry. This list is not limiting.
• nanofiltration membrane comprising at least one porous support membrane, which with, prepared by emulsion polymerization rubbery polymer particles having an average particle diameter smaller than 70 nm and with
• Nanoparticles at least one oxide of the elements Al, Si, Ca, Fe, Mn, Cr, Ti, V, Zn, Zr, Sn is coated for the filtration of water and wastewater and for the purification of drinking water.
• Another invention is the use of the nanofiltration membrane according to claim 1 for the filtration of water and wastewater and for the purification of drinking water. The invention will be explained below with reference to at least one example, which, however, is in no way limiting.
• HEMA Hydroxyethyl methacrylate
• Disproportionated rosin acid (abbreviated as HS) - calculated as the free acid starting from the amount of Dresinate® 835 used (Abieta® DR 835A from Arizona Chemical BV /
• Dresinate® 835 batch used was characterized by the solids content and by the emulsifier components present as the sodium salt, as the free acid and as the neutral.
• the solids content was determined according to the procedure described by Maron, S. H .; Madow, B.P .; Borneman, E. "The effective equivalent of certain rosin acids and soaps" Rubber Age, April 1952, 71-72.
• the mean value of three aliquots of the Dresinate® 835 batch used was found to be 71% by weight solids.
• the emulsifier components present as the sodium salt and as the free acid were determined by titration according to the method described by Maron, S.H., Ulevitch, I.N., Eider, M.E., Fatty and Rosin Acids, Soaps, and Their
• Dresinate® 835 (71%) was dissolved in a mixture of 200 g of distilled water and 200 g of distilled isopropanol, treated with an excess of sodium hydroxide solution (5 ml 0.5 N NaOH) and with 0.5 N hydrochloric acid back titrated. The titration course was followed by potentiometric pH measurement. The evaluation of the titration curve was carried out as described in Analytical Chemistry, Vol. 21, 6, 691-695.
• Dresinate® 835 batch Three aliquots of the Dresinate® 835 batch used were averaged:
• FS Partially hydrogenated tallow fatty acid - abbreviated as FS (Edenor HTiCT N from Cognis Oleo Chemicals, CAS No. 61790-37-2).
• the Automatemulgatorgehalt and the average molecular weight of Edenor ® HTiCT used N-batch were titrimetrically determined using the following methods: Maron, SH, Ulevitch, IN, Elder, ME "Fatty and Rosin Acids, soaps, and Their Mixtures, Analytical Chemistry, Vol 21, 6, 691-695; Maron, SH; Madow, BP; Borneman, E.
• Free Acid FS
• Rongalit C ® Na formaldehyde sulfoxylate 2-hydrate
• Trigonox ® NT 50 from Akzo-Degussa CAS-No.
• Trigonox ® NT 50 from Akzo-Degussa CAS-No.
• styrene-containing Type 5 and g for the acrylonitrile-type 1.7g p-menthane hydroperoxide used which in 200 ml the emulsifier solution prepared in the reactor were emulsified.
• the temperature control during the polymerization was carried out by adjusting the coolant quantity and the coolant temperature in the temperature ranges indicated in the tables.
• the latex was subjected to steam distillation at atmospheric pressure.
• the polymer particles thus prepared are used for a nanofiltration membrane according to the invention.
• Table 2 shows the recipe of the rubbery polymer particles produced; the following indexes are used:
• the support membrane used was an ultrafiltration membrane made of polysulphone which was placed in isopropanol for 30 minutes in a solution of 20% by weight of polyethylene glycol at 400 g / mol prior to processing. This membrane was coated by means of a spiral doctor with an aqueous dispersion.
• the dispersion consisted solely of rubbery polymer particles as described above.
• the mixture of the rubber-like polymer particles consisted by above preparation together with nanoscale particles of type SiC Bindzil ® cc301 and Levasil ® 200/30 [Akzo Nobel Chemicals Holding GmbH, Aachen, (Bindzil ® cc301 CAS No. 141029-67. 7631-86-9)] in a concentration of 5 and 10 -6) (Levasil ® 200/30 CAS-No.%., based on the solids content of the polymer dispersion urpsrün Mi.
• the support membrane was coated at a rate of 20 mm / sec.
• the wet film thickness of the dispersion layer results from the type of spiral doctor blade with about 6.7 ⁇ , resulting in a dry film thickness of the separating active layer of about 1.9 ⁇ results.
• the drying was carried out at about 60 ° C under atmospheric pressure for 30 minutes.
• the filtration properties of the nanofiltration membranes according to the invention were measured with a solution of 2000 ppm MgSÜ 4 in water. This feed solution was applied to the membrane in cross flow under a feed pressure of 5 bar at 20 ° C. and a flow rate of 4 l / min. The salt concentration remaining in the permeate was determined by the conductivity of the solution and related to the concentration in the feed in order to obtain the retention of the membrane.

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