DE3913772A1 - Particles for selective removal of metal complex anions from aq. soln. - has ion-pairing agent dispersed in aq. phase which is present in a gel or encapsulated - Google Patents

Abstract

Particulate agent for selective removal of metal complex anions (I) from aq. soln. comprises an ionic, non-polymeric agent (II), able to form ion pairs with (I), dispersed in a continuous aq. phase which is embedded in a hydrophilic gel, and/or a component of such a gel and/or encapsulated in a water-insoluble, ion-permeable covering. specifically (II) is an amine salt of formulae (R1,R2NH2)+x- or (R1R2R3NH)+X-R11R2 and R3 = 6-20C alkyl (opt. substd. by OR4 or SR4) or aryl (esp phenyl) opt. substd. by 1-3 lower alkyl (esp. me), x = residue of organic or inorganic acid, pref. sulphale, nitrate or halide, esp. chloride. - The agent pref. comprises (by wt.) 0.5-30% gel. forming agent, 1-50% (II); 0-40(10-30)% water-insol. solvent; 0-10% auxiliaries and 40-90% water. Partic. the continuous aq phase is embedded in a thermally-crosslinked gel and encapsulated by a covalently-crosslinked gel. The particles are of dia. 0.1-6(esp. about 15)mm. USE/ADVANTAGE - The method is used to remove (I) for environments protection or recovery of )valuable metals. The particulate agent provides better selectively, ease of handling and efficiency companed with liq-liq extn. processes. The particles have high mechanical stability, provide a large exchange surface and are easily sped. from soln.

Description

The invention relates to a for selective separation of metal complex anions from aqueous solutions particulate agent. The invention further relates to Process for the preparation of the agent according to the invention and its use.

The separation of the metal content from aqueous Has solutions in terms of protecting the environment harmful metals and with regard to the energy-saving extraction or recovery of value metals are becoming increasingly important.

Many metals, especially heavy metals like mercury silver, cadmium, chrome or lead used in industrial, municipal or agricultural waste water available are known to be toxic. It is desirable also the extraction or recovery of the precious metal salary and return to the economic cycle.

The metal ion is often present in the form of metal complex anions in the aqueous solutions. Metal complex anions are negatively charged atom groups from one or more metals, for example main group metals such as lead or tin or subgroup metals such as chromium molybdenum, tungsten, silver, gold, metals of the platinum group such as platinum, palladium, rhodium, and ligands, for example the oxo group, the halides and pseudohalides, nitrates or sulfates, in which the positive oxidation level of the metal or metals are overcompensated by the negative charge of the ligands. Examples of such metal complex anions are CrO ₄ ^2- (chromate), Cr ₂ O ₇ ^2- (dichromate), PtCl ₄ ^2- (tetrachloroplatinate II), PtCl ₆ ^2- (hexachloroplatinate IV) or HgCl ₂ ^- (dichloromercurate).

Process for the separation of metal complex anions from aqueous solutions are already known, for example from T. Sekine, Y. Hasegawa, Solvent Extraction Chemistry, Pages 217 to 235 (1977). For example, one contacts the aqueous solutions in a liquid-liquid extraction with non-polymers, dissolved in organic solvents ionic agents with metal complex anions ions form pairs. These agents are Ver bonds, the functional groups with positive charge have, for example ammonium or phosphonium groups. For example, primary, secondary, tertiary amines in protonated form or quaternary ammonium salts for example the sulfate, nitrate or halide salts, be used.

The way these agents work is known. The Cation of the agent, for example one with long chain organic alkyl groups substituted secondary ammonium group forms with that present in aqueous solution Metal complex anion the corresponding ammonium metallate. The Ion pair, which is advantageously only a solution in water possesses a few ppm in organic solutions agents, for example aliphatic hydrocarbons or kerosene, but is soluble, gets into the organic Phase extracted.  

By treating the separated organic phase with basic or saline, aqueous phase Agent regenerates and the metal complex anion in the transferred aqueous phase, the usual methods is worked.

Depending on the type of ion pair used Agent, temperature, pH and others Process conditions succeed in the selective separation of Metal complex anions.

The well-known liquid-liquid extraction processes require the intensive mixing of the aqueous and the organic phase. Difficulty in phase separation and in the subsequent separation of the formed Ion pairs from the organic phase are significant Disadvantages in this known method.

Polymeric ion exchange resins are for separation of metal complex anions usable, but unselective.

The object of the invention is to overcome the disadvantages of be known means to overcome and release agents with verbes selectivity, manageability and effectiveness develop. This task is solved by the inventions according to the invention, for the selective removal of metal complex anions from aqueous solutions suitable particulate Medium.

The inventive, for the selective removal of Suitable metal complex anions from aqueous solutions Particulate agent contains an ionic, not poly meres, forming an ion pair with metal complex anions Agent dispersed in a continuous aqueous phase se which is embedded in a hydrophilic gel and / or Is part of a hydrophilic gel and / or of one water-insoluble, ion-permeable shell is enclosed.  

"Non-polymer" is used in the context of the present Invention understood that the agent molecule a maximum of 9 itself can have repeating monomer units. Preferably the complexing agent is a monomeric substance. The molecular weight of the agent is expediently below about 1000 daltons.

In the context of the present, "ionic" is used Invention understood that the agent is a cation and a Anion includes.

In the following, a "gel" is a hydrogel Roger that.

Those that can be used in the present invention ionic, non-polymeric, with metal complex anions Agents forming ion pairs are from the prior art Technology known. The mode of operation of this in the invention according to dispersed agents changes present agents in principle not. From the cation and the respective Metal complex anions form ion pairs in water are sparingly soluble and / or in organic solvents are better than soluble in water and as a result aqueous solutions can be extracted.

The cation can precede one or more, up to nine preferably a positively charged functional group point. For the positively charged functional groups For example, it can be nitrogenous, phos act groups containing phosphorus or sulfur. Quality Results are, for example, with primary, secondary, tertiary or quaternary ammonium or phosphonium compound achieved, where branched or unbranched, optionally substituted alkyl with bis to 30 carbon atoms, optionally substituted aryl, esp special phenyl or tolyl. Good results nisse are also with ammonium or phosphonium compound received in which the nitrogen or phosphorus  atom component of aliphatic or aromatic ring systems with 5 to 7 carbon atoms, for example with Piperidinium or pyridinium compounds or the corresponding phosphorus analog groups.

Anions are organic or inorganic Acid residues in question. Acid residues of inorganic acids, especially sulfate, nitrate, halide or pseudohalo genid are preferred. Is particularly suitable as an anion Chloride.

Particularly good results are achieved if that with metal complex anions an agent forming an ion pair is selected from compounds of the general formula (I)

(R¹R²NH²) ⁺X ^- (I)

and the general formula (II),

(R¹R²R³NH) ⁺X ^- (II)

wherein R ¹ , R ² and R ^{3 can be the} same or different and can independently mean: alkyl having 6 to 20 carbon atoms; branched alkyl having 6 to 20 C atoms, optionally substituted by OR ⁴ or SR ⁴ alkyl, where R ^{4 is} alkyl having 1 or 10 C atoms; Aryl, especially phenyl, optionally substituted with 1 to 3 lower alkyl groups, especially methyl; and X ^- organic or inorganic acid residues, preferably as sulfate, nitrate or halide, in particular chloride.

The contained in the agent according to the invention Agent can consist of one, with metal complex anions Compound forming ion pair or from mixtures of several such connections exist.

The skilled worker is aware that the selectivity of the usable agents in the separation of metal complex anions from aqueous solutions essentially depends on the chemical structure of the agent as well as possibly of the pH and the temperature of the aqueous solution.

The person skilled in the art is also aware of the conditions under which conditions in terms of pH and temperature known agents selectively select certain metal complex anions can cut off.

Since the selectivity of the agents in the The use in the agent according to the invention has not changed, the person skilled in the art knows which agents are used need to be a means of separating a desired one To produce metal and under what conditions in terms of pH and temperature, the means for selective separation of metal complex anions used becomes.

The metal complex anions can be the Metal complex anions of main group metals, e.g. from Lead or tin, of transition metals, e.g. of chrome, Molybdenum, tungsten, mercury and precious metals, e.g. trade silver, gold or platinum group metals.  

It should be pointed out again that the above-mentioned, with metal complex anions ions pair-forming agents only an incomplete selection of the agents known to those skilled in the art put. Requirement for usability in the invent Agent according to the invention is that the respective agent in water is sufficiently poorly soluble. Turn out to be cheap agents, for example, whose solubility in water is less than about 10 mg / l water.

The agent can be emulsified or suspended in the aqueous phase per se. A solution of the agent is preferably dispersed in a water-insoluble solvent in the aqueous phase. Particularly suitable solvents for the agent are aromatic-free aliphatic or cycloaliphatic hydrocarbons with a higher boiling point, for example from about 120 ° C. to about 300 ° C., in pure form or as a mixture, for example of C ₁₁ -C ₁₃ hydrocarbons. Kerosene, for example, is also suitable. The agent according to the invention can contain the solvent in an amount of up to about 40% by weight, preferably 10 to 30% by weight, based on the total weight of the finished agent.

If a water-insoluble solvent in the invent is included, the ratio of Amounts of solvent and agent in a wide range fluctuate, for example from about 0.1: 1 to about 20: 1, preferably from about 1: 1 to about 10: 1.

If desired, the agent can also be attached to solid supports substances coupled, for example physically by hydro phobic interaction over longer carbon chains, in the aqueous phase is suspended. This ver driving style is particularly suitable for such agents, which are weakly water-soluble per se and agents whose solubility in water is up to about 1000 mg / l can. By coupling these agents to the fixed  Carrier can bleed out of the invention Means can be prevented.

Known solids with a hydrophobized surface come into consideration as carriers. For example, very fine, for example to a particle size of about 0.01 to 10 micrometers, in particular from 0.1 to 2 micrometers, ground ceramic materials, in particular based on silicon dioxide, can be used. Hydrophobicized silicon dioxide aerogels are very suitable. Such aerogels contain, for example, alkyl, dialkyl or trialkylsilyl groups on the surface which are chemically bonded to the support via three, two or one oxygen atom. Alkyl can be C ₁ to about C ₁₂ alkyl. A silicon dioxide airgel in which octylsilyl groups are chemically bonded to the surface of the support is particularly suitable. Such an airgel is available under the name Aerosil R 805® from Degussa AG, Frankfurt.

In the particles according to the invention, the agent dispersed continuous aqueous phase Be part of a hydrogel or in a hydrophilic Be embedded in gel. So the continuous phase can freely movable in the gel or essentially stationary be bound.

According to the invention, all ver used inorganic or organic hydrogels that are not changing with the agent unwanted effect. It is advantageous to use gels which are stable in the acidic pH range. Organic hydro phile cross-linked gels are preferred.

Organic, hydrophilic gels include covalent and not covalently cross-linked gels and are known to the expert known, e.g. from B. Vollmert, floor plan of the macro molecular chemistry, E. Vollmert-Verlag, Karlsruhe 1979.  

The gels are formed in a manner known per se Cross-linking of corresponding cross-linkable gel precursors (= Gelling agent). The gelling agents can be thermal, that is crosslinkable by exposure to heat or cold or be crosslinkable with the aid of a crosslinking agent. In the gels crosslinked by crosslinking agents do not belong covalently cross-linked gels, which consist of corresponding ono tropical gel formers through crosslinking under the influence of Metal cations or of anions or pH change are formed, and covalently cross-linked gels, their pre step through the implementation with the crosslinking agent Networking covalent bonds.

As a gel precursor of hydrophilic organic gels are many well-known natural products of animal, vegetable or bacterial origin can be used. Gelable products animal origin are, for example, polypeptides such as Gelatin. Gellable products are of vegetable origin for example many polysaccharides, e.g. Pectinate, Alginates, carrageenan, agar or agarose. Bacterial Available polysaccharides are, for example, curdlan or Gellan.

The gel formers also include many modified, that is, chemically modified natural products. The Modifi Ornamentation can, for example, by alkylation, dealkyly tion, carboxylation, decarboxylation, acetylation or Deacetylation etc. take place. As modified in such a way Gelling agents are, for example, derivatized Cel lulose, e.g. Cellulose sulfate or carboxymethyl cellulose, partially deacetylated gellan, also gellable amino sugar-containing polysaccharides, e.g. through partial Deacetylation of chitosan available chitosan.

As gelling agents of thermally cross-linked gels for example polypeptides, e.g. Gelatin, and given if modified polysaccharides, e.g. Agar, curdlan or To call agarose.  

To the gel that can be crosslinked by a crosslinking agent the inorganic precursors and those of Ion-crosslinkable organic ionotropic gelling agent.

Preferred ionotropic gel formers of gels crosslinked by cations (suitable ions in brackets) have a chain of polymeric saccharides as a framework. As a functional group, they have the carboxyl group, such as alginate (Ca ²⁺ , Al ³⁺ , Zn ²⁺ ), pectate (Mg ²⁺ , Ca ²⁺ ), carboxy methyl cellulose (Al ³⁺ ); the phosphonyl group, such as Phospho guargum (Ca ²⁺ , Al ³⁺ ), or the sulfonyl group, such as carrageenan (K⁺, Ca⁺) and cellulose sulfate (K⁺). Also worth mentioning is the gellan crosslinkable by Na⁺, K⁺, Ca ² , Mg ²⁺ or Al ³⁺ , which can also be used in deacetylated form.

Preferred ionotropic gelling agents by anions cross-linked gels have a chain of amino as a framework sugary polysaccharides. As a functional group they have the amino group, which is in protonated form is anionically crosslinkable. One or more hydrogen atoms of the amino group can be substituted, e.g. by Alkyl radicals or acetyl groups. One example is Chitosan, which among other things by tripolyphosphates, hexacyano ferrate (II) and hexacyanoferrate (III) are crosslinked can.

By lowering the pH, i.e. adding one Acid, gellable ionotropic gelling agents that function as funk tional group have acid residues, for example the Carboxy group, the phosphonyl group or the sulfonyl group, are very suitable. To name an example are appropriately substituted polysaccharides, such as Alginates and pectates, which form at pH values <3 Alginic acid or polygalacturonic acid forms.  

Covalently crosslinked, hy drophilic, organic gels can be prepared in a manner known per se se by polyreactions such as polycondensation, polyaddition or polymerization, preferably by polycondensation or polyaddition can be prepared from prepolymers. Preferred hydrophilic poly obtained by polyaddition mers are correspondingly substituted polyurethanes (PU) and Polyureas.

Suitable PU prepolymers are e.g. the types Hypol® FHP 2000, 2002, 3000 or 4000 from Grace, Lexington.

As a covalently cross-linked gel, which in the invention appropriate means can also come through suitable crosslinking agents covalently crosslinked, ionotropic Gel images containing a polysaccharide structure containing amino sugar have, for example chitosan, or thermally crosslinked bare gel formers that have a polypeptide backbone for example gelatin, in question. Suitable crosslinking agents tel are known per se. They contain two or more functional, amine-crosslinking groups; to be designated as such Examples are the aldehyde, isocyanate and thioiso cyanate, azo group. There will be bifunctional networking means used that are water soluble, with water each don't react or react slowly. In particular are to mention diisocyanates, e.g. Tolyl diisocyanate and dial dehyde, e.g. Glutardialdehyde. Gels are very suitable from chitosan, cross-linked with glutardialdehyde.

If the aqueous dispersed contained the agent Phase not part of a hydrophilic gel or in a hydrophilic gel is embedded, it must be from a water-insoluble, ion-permeable shell. It can be useful to increase particle stability this case with yet another additional one to surround the water-insoluble, ion-permeable shell.  

It is advantageous to add an additional one, preferably Even then, agent-free, water-insoluble, ion-permeable shell use when the continuous aqueous phase in a Gel is embedded or is part of a gel. The case causes increased mechanical stability. Besides, will a discharge of the agent into the aqueous solution to be cleaned avoided by enveloping the gel body. This is especially true especially important if the agent is in a solvent is solved. Bs may also need the gel structure before contact with harmful impurities in the To protect water. If a reprocessing of the loaded agent is also intended Wrapping the gel appropriately.

The shell, preferably free of agent, can be obtained from the cross-linked hydrophilic already described above Gels consist of hydrophilic, organic, cross-linked Gels are preferred, in particular ionotropically crosslinked and covalently cross-linked gels.

In addition to the ionotropically crosslinked gels already described whose ion permeable material in question, e.g. Gels, which can be obtained by using two different ionotropic Gel precursors with different functional groups Networked polarity. Examples are from Chitosan, cross-linked e.g. with alginate, pectate, carboxy methyl cellulose, phosphoguargum, carrageenan and / or Cellulose sulfate, called gels obtained.

The envelope can also be made of covalently cross-linked gel be educated. For example, it can be a urea Trade formaldehyde polymer.

It is possible to include in the agent according to the invention tene gels and / or the shell material by chemical modes to reinforce it.  

For example, iono tropical gels or the corresponding covering material with acid be acted. The gel or shell material then contains free, insoluble acids, for example alginic or poly galacturonic acid.

It is also possible to use ionotropic amino sugar to reinforce cross-linked gels through derivatization. For example, crosslinked by tripolyphosphate Chitosan be acetylated. The gel or shell material then contains poorly soluble chitin.

It is also possible to use a non-covalently cross-linked Gel or shell material through additional covalent networking to strengthen the tongue.

It can be particularly beneficial to have a non kova lent cross-linked envelope material with an additional kova strengthen lente networking. For example, a shell material containing amino groups through additional kova lente networking using one of the be described amine crosslinking agents. So for example polypeptides, e.g. Gelatin, or cross-linked ionotropically with tripolyphosphate or hexacyanoferrate te amino sugar-containing polysaccharides, such as chitosan Crosslink covalently with glutardialdehyde.

Disper contains a particularly preferred agent sion in an organic immiscible with water Solvent-dispersed agent dispersed in the aqueous Phase, which in a thermally crosslinked gel, esp special agar or agarose, is embedded with a Shell obtainable by covalent crosslinking of an amino sugar-containing polysaccharides, especially chitosan, with a difunctional crosslinking agent, preferably glutar dialdehyde.  

If desired, the continuous aqueous Phase, possibly also the ion permeation surrounding it ble envelope, one or more aids known per se included to modify the particle properties. As Aids can in particular modify the viscosity rende, preferably viscosity-increasing agents, the Density-modifying agents that influence pH and agents modifying the surface tension be set.

They are already coming as viscosity-increasing agents Compounds described as ionotropic gelling agents in Consider. Carboxy groups are particularly suitable substituted polysaccharides, for example carboxymethyl cellulose, as well as derivatives, e.g. Carboxymethyl cellulose ether.

To lower the density, means with a density of <0.9 g / cm ³ are preferred. These can be, for example, water-insoluble solids, for example foamed plastics or foam glass, or organic water-insoluble substances, for example the aliphatic hydrocarbons, in particular kerosene, which can simultaneously be used as solvents for complexing agents. Water-insoluble agents are preferably used as density-increasing agents with a density of <2 g / cm ³ , for example heavy spar or titanium dioxide.

If desired, can be used as the surface tension modifiers known per se emulsifiers (Ten side) can be used. Emulsifiers with one are cheap HLB value <8, preferably between 8 and 18, that is Oil-in-water emulsifiers. Examples of suitable emulsifiers can be found in Fiedler, H.P., Lexicon of auxiliary substances for Pharmacy, cosmetics and related areas, Aulendorf 1971, pp. 265 to 270. Examples of emulsions that can be used gates are fatty acid esters, e.g. Polyoxyethylene monolaurate (PEG-300), polyoxyethylene (20) sorbitan tristearate (Tween  65), sulfonates, e.g. Alkylarylsulfonates (G-3300), amine salts such as didodecyldimethylammonium chloride, nonionic Alkyl polyglycol ethers, e.g. Emulsogen LP, Hoechst AG, or Combinations of anionic compounds with dissolver mean, e.g. Emulsogen L, Hoechst AG.

The agent according to the invention is preferably in essentially spherical, rod-shaped or thread-like educated.

The diameter of the balls is between 0.1 and 6 mm, preferably the diameter is approximately 1.5 mm. If the agent according to the invention is rod-shaped is present, the diameter of the rods is 0.1 to 6 mm, preferably 1 to 1.5 mm, and the length 2 to 30 mm, preferably 8 to 12 mm. The invention Means can also be in the form of threads whose through knife then 0.1 to about 6 mm, preferably 0.5 to 3 mm can be.

The water content of the particulate agent is between about 40 and 90% by weight. The percentage of agent is about 1 to 50% by weight in the finished gel. The amount of gel former is about 0.5 to 30% by weight. The amount usual tools is between 0 and about 10 wt .-%, the content of water-insoluble solvent between 0 and about 40% by weight, preferably between about 10 to 30% by weight.

The agent according to the invention surprisingly has beneficial properties. So it is characterized by high mechanical stability, especially if the cont liquid aqueous phase into a hydrophilic organic Gel is embedded or is part of such a gel. By an additional coating of the discrete particles the mechanical stability is increased. Hereby, as well as through the possible coupling of the agents Hydrophobic carriers can increase the risk of contamination  nation of the aqueous solution to be treated with the ver agile agents can be avoided.

Another decisive advantage is that the Ion transport through the respective core and Envelope material is made by water, which is the diffusion of the Ions through channels, macro and micro pores to the agents enables. The large exchange area between the agent and transport the metal anion complexes to be separated Continuous aqueous phase leads to higher Effectiveness of the agent according to the invention while maintaining selectivity. At the same time, handling is easy, since the agent is easy to separate from the aqueous solution is.

In the following the preparation of the fiction moderate, for the selective separation of metal complex anions Suitable agents described from aqueous solutions.

The process for producing the invention Means is characterized in that

• a) an ionic non-polymeric agent or a non- ionic precursor of the agent in an aqueous phase dispersed, which is a crosslinking agent, one by a crosslinkable precursor of a hydrophilic gels or a thermally cross-linkable pre stage of a hydrophilic gel
• b) to form particles from the dispersion obtained under a)
  • b1) the dispersion containing a crosslinking agent for encapsulation with an essentially water-insoluble, ion-permeable shell is introduced into a solution which contains a gel precursor of a water-insoluble, ion-permeable shell material which can be crosslinked by the crosslinking agent, or
  • b2) which introduces a heat-crosslinkable or heat-crosslinkable precursor of a hydrophilic gel to form discrete gel particles into a liquid phase which has a temperature which is sufficiently high for the thermal crosslinking of the gel precursor, or a sufficiently low temperature for the thermal crosslinking of the gel precursor Temperature or
  • b3) which introduces a dispersion containing a crosslinking agent precursor of a hydrophilic gel into a solution containing the crosslinking agent or incorporates the crosslinking agent into the dispersion
• c) if a nonionic precursor has been used in stage a), this is converted into the ionic agent
  and if necessary
• d) those obtained in stage b1), b2), b3) or c) Particles with a substantially water-insoluble ion-permeable shell coated and / or a Particle surrounding envelope from a non-covalent cross-linked, amino group-containing envelope material additional covalent networking strengthened.

So you can in stage a) the ionic agent, for example wise ammonium salts, disperse.

However, it is preferred to use nonionic in stage a) Disperse precursors of the agent in the aqueous phase and after the formation of the gel particles, the nonionic To convert the precursor of the agent into the ionic agent. This procedure is possible, for example, if one as an ionic agent in the particulate compound verbin  with primary, secondary or tertiary ammonium want to use groups. As a non-ionic precursor the corresponding compounds are dispersed with free Amino groups that are used in a later stage of Her procedure, if necessary immediately before the Application for conversion into the ionic agent with the contacted aqueous solution of an acid.

The dispersion of the ionic agent or not ionic precursor of the agent in the aqueous phase can according to known methods for generating a Dispersion, i.e. a suspension of solid agents or an emulsion of solid or liquid substances in one aqueous phase. Present in solid form Agents, for example coupled to carrier material, are preferably as particles with a size between 0.1 to 500 µm used. In liquid form, optionally dissolved in water-insoluble solvents ionic agents or non-ionic precursors of Agents are, for example, by high-speed stirrers (Turbo stirrer) processed into an emulsion, in which the emulsified particles have a diameter of about 0.2 to have about 50 µm.

If the production of the particles according to the procedure variant b1) and / or the particles according to Process stage d) are to be surrounded by an envelope, can the dispersion in step a) inorganic or orga African crosslinking agents are added. The choice of Crosslinking agent depends on the gel used formers for the wrapping material.

From the group of inorganic crosslinking agents, tripolyphosphates and hexacyanoferrates are to be mentioned, which crosslink ionotropic gel formers, which, for example, have NH ₃ ⁺ groups, ie are cationically functionalized. Also to be mentioned are salts, preferably salts of metals of the 2nd and 3rd main group, in particular calcium salts, and optionally potassium or NH ₄ salts, the chlorides being preferred in each case. Such salts are crosslinking agents for ionotropic gel formers which contain oxo acid residues as functional groups, for example the carboxyl, phosphonyl or sulfone group, ie are anionically functional, such as alginates or pectates. Also mentioned are acids, for example HCl, which are anionically functionalized ionotropic gelling agents. eg alginates or pectates. network.

The ionotropic ones already described above Gel formers, which in turn are precursors of organic, hy can represent drophilic cross-linked gels also as a crosslinking agent for the production of by Ver wetting different gel formers together standing envelope material. This has a cationic effect functionalized ionotropic gelling agents, e.g. Chitosan, as Crosslinking agent for anionically functionalized ionotropic Gelling agents, e.g. Alginate, and vice versa.

Inorganic or organic crosslinking agents, the can cause a covalent crosslinking of gel precursors NEN can also be used. These include the Agents known per se, which contain a polymer tion, polyaddition or polycondensation of precursors ter formation of a hydrophilic covalently crosslinked gel Act. If as a gelling agent for the wrapping material Polyurethane prepolymer can be used, the water itself, possibly under the influence of reaction accelerate, act as a crosslinking agent.

Examples of organic crosslinking agents, the one Covalent cross-linking are connections that have amine-crosslinking functional groups. Such Groups are, for example, the aldehyde, isocyanate, Thioisocyanate or azo group. Preferably, di functional crosslinking agent used, which water are soluble, but not or only slowly with water  react. In particular, diisocyanates, e.g. Tolyl diisocyanate, or dialdehydes, e.g. Glutardialdehyde.

If the production of the particles by process Variant b2) or b3) should take place, the dispersion in step a) one of the gel formers described above added.

In step b) particles are formed from the obtained dispersion.

If the dispersion contains a crosslinking agent, after stage b1) it is encapsulated with an im essential water-insoluble ion-permeable shell in introduced a solution, one through cross-linking medium crosslinkable gel precursor of a water-insoluble contains ion-permeable covering material. As a solution preferably an aqueous solution is used. The bringing in can, for example, by dropping or injecting it consequences.

Preferred combinations of crosslinking agent / orga Niche cross-linkable precursors are salt / ionotropic gel formers and cationically (anionically) crosslinkable iono dropper gelling agent / anionic (cationic) crosslinkable ionotropic gelling agent.

If the dispersion thermally ver wettable or thermally crosslinkable preliminary stage contains a hydrophilic gel, it is used for training discrete gel particles after stage b2) in a liquid pha se introduced, which is one for thermal crosslinking of the Gel precursor has a sufficiently high temperature, or which one for thermal crosslinking of the gel precursor has a sufficiently low temperature. The introduction can for example by dropping or injecting. If you use a gel precursor that can be cross-linked by cold sets, one uses, for example, aliphatic coals  hydrogen, or aromatic-free hydrocarbon mixtures or kerosene, but preferably water. Unless you have one heat-crosslinkable gel precursor one a higher boiling water-insoluble organic Hydrocarbon or silicone oils.

The temperature is sufficiently high for crosslinking depends on the respective gel precursor and the specialist known. For curdlan, for example, it is about 65 ° C. However, thermal crosslinking is preferably carried out at a temperature that is significantly higher than that just enough temperature for crosslinking at for example at a temperature that is about 15 ° C to 60 ° C higher tur, by.

As a sufficiently low temperature in cold weather A temperature is measured for thermally crosslinkable gels hen which is at least 15 ° C lower than the temperature, where the gel changes to the solution state. The tem The temperature at which this transition takes place is from the respective gel dependent and known to the expert.

If the dispersion obtained in stage a) is a precursor of a hy which can be crosslinked by means of a crosslinking agent contains drophilic gels, the dispersion is made up Step b3) into a solution containing the crosslinking agent or the crosslinking agent works in the dispersion a. The introduction of the dispersion into the solution can for example by dropping or injecting and is carried out especially when as cross-linkable Precursor an ionotropic gelling agent is used. The The crosslinking agent can be incorporated into the dispersion for example, by intimate mixing. It is coming especially when the networking is a Is polyreaction, i.e. polymerization, polyaddition or Polycondensation.  

Unless you have a non-ionic precursor in stage a) used, one transfers after the formation of particles the non-ionic precursor of the agent into the ionic Agent. Has one in the aqueous phase in stage a) as not ionic precursor of the agent, for example primary, dispersed secondary or tertiary amines are contacted the particles obtained in step b1), b2) or b3) for example by dipping or spraying with a Acid preferably an aqueous dilute acid, esp especially a mineral acid, particularly preferably with aqueous dilute hydrochloric acid and thereby transfers the Amines in the ammonium compounds and thus in that ionic agent.

Those obtained in stage b1), b2), b3) or c) Particles can, if desired, in step d) with an im essential water-insoluble, ion-permeable shell be layers and / or a shell surrounding the particles a non-covalently cross-linked amino group Envelope material through additional covalent cross-linking be reinforced.

For coating, for example, you can use a contacted solution containing crosslinking agent, for example wise by dipping or spraying. Then con clocking the particles pretreated in this way, e.g. again by immersion or spraying, with a solder solution that ver by the crosslinking agent used contains wettable gel precursor for the coating material. By the reaction between cross-linking center and cross-linkable The desired shell is created in the preliminary stage.

The particles are preferably contacted first ent a crosslinkable gel precursor of the coating material holding solution and cross-links this cross-linkable gel preparation fe afterwards. The networking can be done in a known manner respectively. Depending on the type of gel former used, the Networking e.g. in the above be  through thermal crosslinking or through Contact with a suitable crosslinking agent be performed.

The particle is preferably coated with a hydro phile organic ionotropic gelling agents, for example by immersion in a solution containing them. On then the particle is immersed in a suitable Ver wetting bath.

The gel precursor of the coating material can be crosslinked also by the diffusion of one contained in the particle Crosslinking agents are triggered on the surface.

If desired, you can use the gel of core and / or Modify envelope material chemically for reinforcement. At for example, cationically cross-linked ionotropic gels contact with an acid and produce gels that insoluble free acid ent of the gel material used hold. Calcium alginate gel can be acidic at pH <3 be converted into alginic acid gel.

There is also the possibility of anionically cross-linked to convert ionotropic gels into poorly soluble derivatives. Chitosangel crosslinked with tripolyphosphate can thus Acetylation can be transferred to Chitingel.

Finally, non-covalently cross-linked amino group-containing gels for additional reinforcement with a Crosslinking agents are contacted, which amino groups is able to covalently network.

In a preferred embodiment, inventions are made particles obtained in accordance with the invention with amino group-containing non-covalently cross-linked wrapping material for additional covalent reinforcement of the shell with a crosslinking agent tel contacts which amino groups covalently crosslink zen can.  

The non-covalently cross-linked envelope material can for example a thermally cross-linked polypeptide such as Gela tine or anions, e.g. Sodium tripolyphos phat, ionotropically cross-linked amino sugar-containing polysaccha be rid like chitosan. Of the be written cross-linking agent comes in particular Glutardialdehyde in aqueous solution in question. The contact Animals can be immersed or sprayed, for example of the particles.

A gel-coated particle can be in one Step (= one-step). A variant for the one-step production of a gel-containing, coated Particle is characterized in that one in Stage a) obtained dispersion, which is a crosslinkable Contains precursor of the gel to be formed in the particle, and a second liquid which is a gel precursor of the Contains wrapping material, so together in a third Liquid enters the dispersion from the second Liquid is surrounded.

This can be done by enters dispersion obtained through a nozzle which of is surrounded by a tube supplying the second liquid. In particular, drop-in and injection are included under input zen understood.

In the dispersion of stage a) and the second rivers liquid precursors can be used, which are based on un can be networked in various ways; the combination of Can be cross-linked by heat and cross-linked by cold Prepress is excluded. For example as in the dispersion of stage a) one by a ver wetting agent crosslinkable preliminary stage and in the second Liquid is a thermally crosslinkable precursor of a gel provide. One can also, for example, in the dispersion from stage a) a thermally crosslinkable gel precursor and in  the second liquid is one by a crosslinking agent crosslinkable gel precursor. The crosslinking agent can then in the third liquid and / or in the dispersion from stage a) which is the thermally crosslinkable gel precursor contains, be included.

Preferably used in the dispersion Stage a) and gel precursors in the second liquid, wel Network in the same way. So it can be to be thermally crosslinkable by heat or by cold act thermally crosslinkable precursors. In this case the third liquid is one for thermal crosslinking Sufficiently cold or sufficiently warm liquid phase. You can also use gel precursors that are made by a Crosslinking agents, especially those already mentioned ionotropic gelling agent. In this case contains the third liquid has a corresponding crosslinking medium.

Another variant for the one-step production of gel-containing, coated particles in one step is particularly suitable for the production of particles in which a thermally cross-linked gel with a shell made of one ionotropically crosslinked gel is coated.

This variant is characterized in that a dispersion obtained in stage a), which is a ther to form a crosslinkable precursor of the in the particle the gel and a crosslinking agent, which is ionotropic gel precursors are able to cross-link in a thermal Crosslinking sufficiently cold or sufficiently warm water solution of an ionotropically crosslinkable gel precursor for the Envelope material enters.

The input can be done, for example, by dropping or injection. When entering the dispersion in the aqueous solution set the thermal crosslinking and ionotropic crosslinking simultaneously. It is formed  discrete, gel-containing particles in one step, which with an ionotropically cross-linked and agent-free gel are enveloped.

The ones already described can be used thermally crosslinkable or ionotropically crosslinkable gel stages and corresponding crosslinking agents. Preferably are added to the dispersion of stage a) by cold thermally crosslinkable precursor for the gel, e.g. Agar, and an anionic crosslinking agent for the envelope material, e.g. Sodium tripolyphosphate. Crosslinked as ionotropic bare gel precursor of the coating material is preferably used a polysaccharide containing amino sugar. That through this preferred embodiment of the manufacturing process The inventive agent obtained consists of discrete Particles with a thermally cross-linked core and ionotropic ver net, shell containing amino groups.

If desired, the discrete particles can be used Reinforcement of the shell, as already described above, modify chemically, especially with a cross-linking medium covalent networking. The discreet obtained here Particles have a thermally cross-linked core and a covalently networked shell.

If desired, the continuous aqueous phase which is the ionic agent or a non-ionic Precursor of the agent contains dispersed, or the ver containing wettable gel precursor of the coating material Solution the viscosity, density and / or Surface tension modifying common tool clog.

The addition of auxiliaries that ver change, especially increase the viscosity, should prevent change that the dispersion produced in stage a) in stage b) loses the desired shape when connected. The setting viscosity is particularly important for thermal  networkable precursors. The optimal amount of viscosity increasing aids depends on the temperature the dispersion. You can, however, through targeted experiments can be easily determined.

The following are those with Roman Numerals denote preferred variants of manufacture proceeded in more detail. This will be followed by the general working instructions in each case boundary conditions for ingredients and concentrations in tabella rical form summarized.

• I. Preparation of an agent according to the invention, in wel chem the continuous aqueous phase of one ion-permeable, agent-free shell is wrapped.
• II. Preparation of an agent according to the invention, which a hydrophilic, non-covalently cross-linked gel ent holds.
• III. Production of an agent according to the invention, which a hydrophilic, covalently cross-linked organic gel contains.
• IV. Coating particles according to the invention with an im essential water-insoluble, ion permeable Cover.
• V. One-step process for the preparation of a gel and provided with an ion-permeable cover agent according to the invention.
• VI. Method for reinforcing a non-covalently ver net wrapping material by transferring it into a kova lent cross-linked wrapping material.

The particles thus obtained can, if desired again with distilled water for further cleaning be rinsed and / or sorted by size.

When describing the individual variants, the general term "dispersion" for both suspensions as well as used for emulsions. The Her position of such suspensions and emulsions ben.

A1) Production of Usable According to the Invention Suspensions

If necessary, the agents present in solid form are first ground, for example in a cross beater mill with sieve inserts of different sizes, until the particle size is in the range from 0.1 to 500 μm. The powder obtained is then mixed with the liquid, the crosslinkable precursor or the crosslinking agent-containing aqueous phase, prior to, during or after the mixing usual auxiliaries, for example BaSO ₄ or TiO ₂ to increase, foam glass or an aliphatic hydrocarbon or mixture Lowering the density, a surfactant or a thickening agent can be added. Mixing takes place with known devices, for example with stirrers.

A2) Preparation of a suspension containing the Ion pair-forming agent coupled to a hydropho supported carrier material

The ionic agent or a non-ionic precursor of the ionic agent is in an organic solution medium, e.g. Acetone, dissolved. Then the solution with hydrophobized carrier material, e.g. hydrophobic Silica airgel, brought into contact, for example in a stirred reactor. One can find the solution of the agent for example also about the Trä placed in a column  abandon germ material. The weight ratio of agent to Backing material should range from about 0.5: 1 to 1.5: 1, preferably about 1: 1.

The solvent is then removed and the obtained solid as described under A1) delt.

B) Preparation of emulsions

Those in liquid form, optionally in water-insoluble solvents dissolved ionic Agents or non-ionic precursors are used in the liquid, a crosslinkable gel precursor or a ver wetting agent-containing aqueous phase stable emul greed, optionally with the addition of modifying Agents, for example thickeners and / or Surfactants, and using high speed stirrers (Ultra-Turrax). The preferred particle size of the emul gated components is between about 0.2 and 50 microns.

There is also the option of starting one to produce concentrated emulsion, if necessary which can contain crosslinkable gel precursor, and the emulsion obtained by subsequent dilution to bring desired concentration.

In a variant, before or during the manufacture development process of the emulsion a modifying agent admitted. For example, the addition of finely ground lenem barite or TiO₂, in a concentration up to about 10 wt .-%, for example from about 0.5 to 10 wt .-% of the finished dispersion, an emulsifier up to about 3% by weight, e.g. about 0.5 to 3% by weight or an agent for changing tion, in particular to increase the viscosity, for example wise sodium alginate, carrageenan, sodium pectate, carboxy methyl cellulose etc. in a concentration up to about 5 % By weight, for example from about 0.5 to 5% by weight  preferably about 2 to 2.5% by weight. Here is to start notice that some of the substances used, for example as the organic ionotropic gelling agents, from Naturpro products and their properties (Vis viscosity, gelling ability etc.) may vary. The pro Centers are therefore only to be understood as approximate values hen.

I. Preparation of an agent according to the invention, in which is the continuous aqueous phase of an ion permeable, water-insoluble envelope is enclosed.

In a first stage a) is already described ner a dispersion of an ionic agent or non-ionic precursor of the agent, if necessary under Addition of other modifying agents (heavy spar, Surfactants, viscosity-increasing agents) in an aqueous Solution of a crosslinking agent prepared. The one here obtained solution becomes the encapsulation, according to the Stage b1) of the process, dropped into a solution or injected, which one through the crosslinking agent contains crosslinkable gel precursor. This forms the contact point between the dispersion solution and the die Solution containing gel precursor a shell, and demented drops stabilized by wrapping material speak or get threads. After a post-reaction phase of about 10 to 20 minutes, the formed, discrete Particles sieved. Unless you have the non-ionic precursor of the ionic agent has been dispersed non-ionic precursor in the ionic agent. One has for example as a non-ionic precursor primary, dispersed secondary or tertiary amines, be it as pure substance, as a solution in a water-insoluble Solvent or coupled to a carrier material, if you contact the gel particles with an acid, especially an aqueous acid solution, preferably an aqueous mineral acid solution, especially hydrochloric acid. The concentration of the acid can be, for example, between  0.1 and 20% by weight, preferably 0.5- up to 2 normal acid solutions. The particles can directly be used as such or a further Nachbe act, for example to reinforce the shell, under will be thrown.  

Table I

Agent in which the continuous aqueous phase is enclosed by an ion-permeable, water-insoluble shell

II. Preparation of an agent according to the invention particles a hydrophilic, non-covalently cross-linked Gel included.

In stage a) is first described as above an aqueous dispersion of the ionic agent in question or a non-ionic precursor of the agent, which a crosslinkable gelling agent and optionally contains other modifying agents.

In stage b) are obtained from that obtained in stage a) Dispersion particles formed.

For this purpose, either ther mixed cross-linking or one after stage b3) Crosslinking of the gel precursor using a crosslinking agent causes, as a crosslinking agent acids or salts be used.

II.1. Formation of hydrophilic, non-covalently cross-linked organic gels due to temperature change.

The thermally crosslinkable gel formers include the can be cross-linked by heat, i.e. by increasing the temperature and that by cold, that is, by lowering the temperature crosslinkable gelling agent. From the first group are in front all gelatin, agar and agarose to name a while Example of the second group is Curdlan.

II.1.a) Cross-linking by lowering the temperature

Gelatin (10 to 30% by weight), agar or agarose (approx 0.5 to 4 wt .-%) are added to water, the ionic Agent or a nonionic precursor of the agent in the dispersed aqueous phase and this optionally other modifying agents, especially viscosity increasing agents, e.g. Carboxymethyl cellulose (approx  0.2 to 5 wt .-%) added. It is heated to about 40 up to 80 ° C and drips or splashes in cold water, e.g. of about 15 ° C. This forms solid, discrete parts chen. Unless you have the non-ionic precursor of an agent dispersed, is transferred as described under I, this precursor in the ionic agent.

II.1.b) Networking by increasing the temperature

Curdlan (2 to 15% by weight) is suspended in water, disperses the complexing agent and adds given if usual aids too. Then you warm up until the curdlan dissolves, but not higher than about 60 ° C, and then drips into hot oil, e.g. Mineral oil or silicone oil (Temperature about 80 to 120 ° C). They form immediately solid particles that can be rinsed off and used if necessary after the transfer described in I. a non-ionic precursor in the ionic agent.

II.2. Gelling through acid

Inorganic gels that can be gelled by acid (pH reduction) Gelling agents are e.g. cationically crosslinkable ionotropic gel formers, especially sodium alginate or sodium pectate.

First, the gel former and the ionic Agent or a non-ionic precursor of the agent ent holding aqueous dispersion.

The finished dispersion is used to form the gel in an aqueous solution of an acid, for example salt acid (about 1-normal) introduced. Here, the desired particulate agent obtained. Depending on Procedure can be pearl-shaped or thread-like Create particles. By dropping the gellable Dispersions in the acid are, for example, pearl-shaped Particles are obtained while threads are being injected will. By varying the dropping speed,  Drop size, injection speed, diameter of the Injection nozzle etc. can be of droplet and diameter Adjust the threads to the desired size. To complete The gelling process can begin immediately discrete particles remain in the acid for 30 min Gelling process and post-reaction phase preferred in the room temperature. Then the discrete ones Particles taken from the acid, e.g. by sieving, and rinsed with water. The particles obtained can be directly used or subjected to post-treatment, e.g. surrounded with an additional ion-permeable shell will.  

Table II 1.

Agent containing temperature-crosslinked gels

Table II 2.

Agent containing gels gelled by acid or base

II.3. Gell by crosslinking with a salt.

Preferred ionotropic gelling agents, which are formed by salts with cations or anions suitable for crosslinking are the soluble compounds, especially the Sodium salts of polysaccharides, for example with the carboxyl, sulfonyl or phosphonyl group substi are acted upon, such as alginate, pectate, carboxymethyl cellulose, Phosphoguar gum, carrageenan, cellulose sulfate; or but amino sugar-containing polysaccharides such as chitosan.

In the first step, the dispersion of the agent or a non-ionic precursor containing a crosslinkable gel preparation stage is prepared. The preferred procedure is to add the gel former to the preferably deionized water and to dissolve it and, if necessary, to add modifying agents. When chitosan is used, the dissolution is supported in a manner known per se by the addition of acid, for example acetic acid. The agent or a nonionic precursor is then dispersed in this aqueous solution in the manner described. If mixtures of gel formers are used, combinations of chitosan with the other gel formers described above are excluded. The formation of particles is carried out by dropping or injecting, for example via a nozzle, into a liquid containing the crosslinking agent. If Chi tosan is present as a gel former, it is added dropwise to an aqueous solution which contains alkali metal tripolyphosphate, potassium or sodium hexacyanoferrate (II) or (III). If the other gel formers mentioned above (except chitosan) are present, the gelable liquid is preferably dripped or sprayed into an aqueous solution containing a salt of polyvalent cations, in particular alkaline earth metal, particularly preferably Ca salts, for example CaCl ₂ . The beads or threads formed in the crosslinking bath can still be used for about 30 minutes to complete the crosslinking. are stirred in the crosslinking bath using a hanging stirrer. The particles are then separated from the crosslinking bath and rinsed off with water. If the non-ionic precursor of the agent has been dispersed, this precursor is transferred to the ionic agent as described under I. The particles can then be used or provided with an ion-permeable shell in a further treatment step.

Table II 3.

Agent containing gels crosslinked by salts

III. Preparation of an agent according to the invention, which is a hydrophilic, covalently cross-linked organic Contains gel.

In general, the first step is the ionic agent or a non-ionic precursor and, if appropriate modifying agents and a prepolymer of the subject Gels mixed with water. Suitable prepolymers are e.g. Acrylic acid, acrylonitrile, acrylamide, polyol / diisocyanate Mixtures, polyurethane prepolymer, etc. The polyreaction is triggered in a manner known per se, by addition of crosslinking agents, chain starters, heating, addition of hardeners etc.

For example, in the first step, the agent or a non-ionic precursor with an amount of up to 40% by weight in polyurethane prepolymer, for example Hypol FHP 2000 from Grace, Lexington, and the (possibly deionized) water mixed, where appropriate density-modifying agents such as heavy spar up to 5% by weight can be incorporated into the mixture. After 10 to The finished mixture is placed in a hardening solution for 20 min. for example an aqueous 0.1% polyaminoamide hardener solution (XE 430 from Schering), dripped or soaked splashes. The resulting drops, sticks or Threads become from the hardener solution after about 30 minutes taken and cured. Unless you have a non-ionic Has dispersed the precursor of the agent, how I described this precursor in the ionic agent. After about 10 to 20 hours, the cured, discrete particles used or an aftertreatment stage are fed.  

IV. Coating particles according to the invention with a essentially water-insoluble ion-permeable shell

The above-described inventive After their preparation, agents can be used to separate Ions from aqueous solutions are used.

However, they are preferred after their manufacture with an essentially water-insoluble, ion-per surrounding meablen shell. This preferably agent-free shell leads to additional stability of the discrete particle and reduces the risk of bleeding.

Particle made in any way medium can be surrounded by a covering which by a hydrophilic covalent or non-covalent ver net organic gel is formed. The combination ver different particle materials and shell materials is in general not critical.

Variant A: Hydrophilic, not covalently cross-linked organic wrapping materials

Discrete particles with a hydrophilic ver meshed enveloping material are generally prepared by converting the discrete particle into one that ver rivers containing wettable gel precursor of the coating material liquid is immersed and so applied to the particle brought cross-linkable precursor in a manner known per se is networked, for example by changing the temperature or contact with a crosslinking agent.

A a) Cross-linking by temperature change

Preferred gel precursors (gelatin, agar, agarose, Curdlan), their concentration and the procedure for ver are analogous to that in II.1. described method.  

A b) Crosslinking using a crosslinking agent

The discrete particle becomes one, the crosslinkable Submerged liquid containing the precursor and then placed in a crosslinking bath. The reverse order is also possible.

Entering the crosslinkable gel precursor of the Wrapping material in a crosslinking bath can be avoided if a crosslinking agent is already present in the particles hold, and this by diffusion into the shell material can transgress and bring about networking.

Discrete particles, the gel of which is crosslinked by ionotropic gelling agents e.g. Alginate, pectate, carboxyme ethyl cellulose, phosphoguar gum, carageenan and cellulose sulfate was produced with calcium chloride, against if necessary after cleaning the surface by rinsing with deionized water, methanol, ethanol etc., in a aqueous solution dipped one or more of the above standing gel formers described in a total concentration tion of about 0.1 to 3 wt .-%, preferably 0.2 to 0.8 % By weight. Calcium ions in the gel of the particle shaped means are included, diffuse into the Lö solution of the gelling agent and cause the formation of a complex-free gel shell around the discrete particle.

In a similar way, envelopes can be made with Acid crosslinkable gel precursors without additional crosslinking Apply the treatment bath to discrete particles that correspond containing acidic ingredients.

Variant B) Hydrophilic, covalently cross-linked organic Wrapping materials

This is the particle used to manufacture the shell shaped means immersed in a prepolymer and in known Way triggered the crosslinking of the prepolymer. Example the discrete particle becomes a water-containing one Polyurethane prepolymer of the type already described, e.g. Hypol FHP 2000, immersed, sieved and in a 0.1% Polyaminoamide hardener solution dipped. After curing with a hydrophilic, covalently cross-linked gel cloaked discrete particle.

Preferred combinations of crosslinkable precursors and crosslinking agents and corresponding concentrations areas are summarized in Table IV below poses.  

Table IV

Precursors and crosslinking agents for wrapping material

V. One-step process for the preparation of a gel containing and provided with an ion permeable shell agent according to the invention

Process variants are described in the following which the gel-containing particles (core material) and vice versa producing shell in a one-step process can be.

V a) Preparation by coating a gel precursor of the core material containing dispersion with a Gel precursor for the second shell-containing material Liquid and subsequent crosslinking by input into a third liquid

Here, the crosslinkable precursor of the gel and the ionic agent or a non-ionic precursor of the agent dispersed aqueous dispersion the gelation or polymerization of the gel precursor with a containing a gel precursor of the coating material Surrounding liquid. A mix of the two Liquids can be adjusted by adjusting different Viscosity can be avoided.

In a preferred embodiment, gel precursors are the core material and the gel precursors of the coating material rials can be networked in the same way. This embodiment is for the hydrophilic, non-covalently cross-linkable, or ganic gel precursors, especially ionotropic gel formers, suitable as core and shell material. By a suitable one Device, for example a nozzle arrangement with zen central outlet for the gel precursor of the core dispersion containing materials and a concent Trisch arranged outlet opening for the gelvor stage for the liquid containing envelope material can e.g. a structure consisting of core dispersion, surrounded by  the enveloping liquid, introduced into a crosslinking bath will. Networking takes place in a known manner.

You have a non-ionic precursor of the agent dispersed, this precursor is transferred as in I described in the ionic agent.

For the particularly preferred embodiment below The use of ionotropic gelling agents is shown in Table Va Kon centering information given. The concentration on Agents and auxiliaries is analogous to Table II.  

Table Va

One-step process for the production of coated, gel-containing particles

V b) One-step process for the production of um enveloped gel-containing particles with thermally cross-linked Core and ionotropically cross-linked shell by entering a a thermal crosslinkable gel precursor and a crosslink dispersion containing an ionotropic agent crosslinkable gel precursor of the coating material containing liquid

A dispersion of an ionic agent or non-ionic precursor of the agent in water becomes a thermally crosslinkable, preferably thermally by cold crosslinkable gel precursor, e.g. a thermally cross-linkable Polypeptide, e.g. Gelatin (10 to 30 wt .-%) or preferred a thermally cross-linkable polysaccharide, e.g. Agar or agarose (about 0.5 to about 4% by weight) optionally agents modifying particle properties, for example viscosity-increasing agents such as carboxymethyl cellulose, also a crosslinking agent, in particular a for crosslinking amino sugar-containing polysaccharides such as Chitosan suitable crosslinking agent, for example a Alkali tripolyphosphate or alkali hexacyanoferrate (II) or (III) at a concentration of about 0.2 to about 4 wt .-% added. The solution obtained becomes about 40 tempered to 80 ° C and in a cold aqueous solution sprayed or dropped ionotropically crosslinkable gel precursor, in particular in an approximately 0.1 to approximately 5% by weight aqueous solution solution of an amino sugar-containing polysaccharide for example Chitosan. As a result of thermal crosslinking of the Core material through cooling and ionic crosslinking discrete particles are obtained in the shell. These will separated and optionally washed with water.

You can, if necessary, as in I be written transfer of the non-ionic precursor in the ionic agent can be used directly as such or an aftertreatment, for example for reinforcement the envelope.  

Table V b)

One-step process for the production of the coated, gel-containing agent with a thermally cross-linked core and ionotropically cross-linked shell

VI. Method of reinforcing a non-covalent cross-linked shell material by transferring it into a covalent one cross-linked wrapping material

Here, an existing shell is made from a amino group-containing non-covalently crosslinked gel, wel ches, for example, by crosslinking amino sugar gene polysaccharides, for example chitosan, with anio African crosslinking agents, e.g. Sodium polyphosphate or Potassium hexacyanoferrate (II) or (III) was obtained with a further crosslinking agent, which two or several functions suitable for crosslinking amino groups light groups, e.g. Aldehyde or isocyanate groups, be sits, brought into contact, e.g. by immersion. One good a suitable crosslinking agent is glutaraldehyde in aq solution. The concentration of this solution can vary between about 0.1 and 50 wt .-%. The transfer of the non- covalent networking is a covalent networking even at room temperature after about 15 to 180 min completed. The degree of networking can be varied by varying the Amount of crosslinking agent can be influenced.

The agent according to the invention can be used to undesirable, harmful or corrosive Separate metal complex anions from aqueous solutions.

The agent according to the invention can also be used be to the content of valuable metals from aqueous Winning or winning solutions. So at for example in the form of metal complex anions metal content of waste water from electroplating baths Precious metal leaching process or the catalyst position separated and reused will.  

Depending on the type of ionic agent used, this can Means according to the invention can be used to a variety selectively from metal complex anions from aqueous solutions remove.

Metal complex anions can be separated, in which at for example main group metals such as lead or tin, minor group metals, for example vanadium, chromium, manganese, Tungsten, molybdenum, iron, cobalt, nickel or mercury as well as the precious metals, for example silver, gold or Platinum group metals, for example palladium, Rhodium or platinum, with known ligands, for example the oxo group or the anions of mineral acids, for example halogen, pseudohalogen, nitrate or Sulfate ligands are present in complex form.

For example, separation from Oxometalates, for example molybdate, tungstate, chromate or dichromate. The separation is also successful, for example of tetrachloroferrate, dichloromercurate, tetra chloropalladate (II), tetra- or hexachloroplatinate (II), Hexachlororhodate.

Because of the selectivity of the invention By means of the possibility also opens up specifically certain metal complex anions from mixtures of substances Use correspondingly selective ion pair forming to separate ionic agents. For example, it is possible when using tri-iso-octylammonium compound Platinum from a platinum and rhodium containing Separate solution with enrichment.

Process for the separation of metal complex anions from aqueous solutions by the agent according to the invention batchwise or continuously, e.g. in flow reactors respectively.  

This is preferably regenerated with a metal complex anions loaded with anions. It is advantageous that after the Regeneration of metal complex anions essentially freed particulate agents again to separate Metal complex anions can be used.

It is not only those skilled in the art who are metal complex anions agents binding themselves with ion pair formation, son they also know how they are regenerated. In the same way known per se can also that, loaded with metal complex anions, the agent disper yeast-containing agents regenerated will.

For example, ion pairs of metal complex anions with primary, secondary or tertiary Ammonium cations are known to be treated with regenerated basic aqueous solutions or saline can be. Accordingly, one with a metal complex anion-loaded agent according to the invention, which as Agent's primary, secondary or tertiary ammonium compound contains dispersed dung, also by aqueous solution be regenerated with an alkaline pH.

If desired, the separated metal catio nen, especially of valuable metals such as precious metal len, from the basic solution or saline solution in itself be isolated and worked up in a known manner.

The following examples are intended to illustrate the invention explain without restricting their scope.

example 1 1. Preparation of alginic acid gel particles which a suspension of carrier material hydrophobized coupled di-iso-tridecylammonium chloride as ionic Agent included 1.1. Coupling of di-iso-tridecylamine as not ionic precursor to the carrier material

Aerosil 805® from Degussa, a silica airgel hydrophobized by means of octylsilyl groups, was used as the carrier material. For coupling to this carrier material, 45 g of di-iso-tridecylamine (available from Fä. Hoechst as "HOE F 2562 ^R ) were dissolved in 350 ml of acetone and stirred in a round bottom flask with 45 g of Aerosil 805®. The solvent was removed in vacuo and the solid product obtained (yield: 88 g finely powdered.

1.2. Preparation of the alginic acid gel particles

12 g were added to 300 g of deionized water Sodium alginate dissolved and diluted with 185 g of water. In 55 g of the finished solution according to 1.1. received Solid using a high-speed stirrer (Ultra-Turrax) suspended. The suspension obtained was dripped into a 2% calcium chloride solution, whereby immediately formed gel pearls. After 25 minutes the Sieved gel beads and to convert the amine into the Ammonium compound a 3.5% aqueous hydrochloric acid solution brought in. This formed from the non-ionic Precursor, namely the amine, the ionic agent that acts on the carrier material was coupled. At the same time the calcium alginate was converted into alginic acid gel.

Example 2 Production of gel particles which are the ionic agent emulsified included 2.1. Preparation of alginate gel particles containing an emulsion of tri-iso-octylammonium chloride dissolved in an aromatic-free aliphatic hydrocarbon Ge mix

50 g of tri-iso-octylamine (available from Hoechst as "Hostarex A 324®") was used in 200 g aromatic-free aliphatic hydrocarbon mixture with a boiling range of 180 to 210 ° C (available from from Shell as "Shell Sol T®"). Furthermore was a sodium alginate solution by dissolving 19 g Sodium alginate (Protanal LF 20 / 60®) in 480 g deioni water and then dilute with 300 g deionized water. The one obtained here Alginate solution, the solution of the amine in the hydrocarbon Mixture and an emulsifier (Emulsogen L®, Hoechst) were made using a high-speed stirrer (Ultra-Turrax) processed a stable emulsion. About 1 up to 2 wt .-% emulsifier, based on the amine, required. The particle size of the emulsified oil droplets was approximately 25 µm. The emulsion obtained was poured into a 2% CaC1, solution dripped, gel beads immediately obtained were. After 30 minutes stir in the crosslinking liquid The pearls were sieved and put into a 10% Hydrochloric acid solution immersed. The amine as non-ionic Precursor was hereby converted into the ionic agent, namely in tri-iso-octylammonium chloride. The calcium algi nat simultaneously converted to alginic acid gel. The Pearls obtained could either be used can be supplied or in a further treatment stage can be provided with an ion-permeable shell. The pearls obtained had a diameter of about 3 to 4 mm.

2.2. Production of alginic acid gel particles, containing an emulsion of di-iso-tridecylammonium chloride in a solvent

The example 2.1. was repeated, however as non-ionic precursor di-iso-tridecylamine HOEF 2562®, Hoechst) was used. Further processing he followed as in Example 2.1. described.  

2.3. Production of alginic acid gel particles, containing a solvent-free emulsion of Di-iso-tridecylammonium chloride

The example 2.1. was repeated. However, there were 160 g di-iso-tridecylamine in 800 g of the alginate solution emulsified. The further processing was carried out as in 2.1. described.

2.4. Production of alginic acid gel particles, containing the emulsion of a mixture of tri-n-octyl and tri-n-decylammonium chloride

The preparation was carried out according to that in Example 2.1. specified procedure, being as non-ionic Precursor a mixture of tri-n-octyl and tri-n-decylamine (Hostarex A 327®, Hoechst AG) was used. The further processing was carried out as in 2.1. described.

Example 4 Coating the discrete particles with an im essential water-insoluble, ion-permeable shell 3.1. Coating with a shell Calcium alginate gel

CaCl was used as the crosslinking agent. To About 150 g of the impregnation with the crosslinking agent pearls obtained according to Example 1 or 2 in 2% Given CaC1, solution and left in it for about 2 hours, sieved, contained with deionized water, washed and surface dried in air for about 15 minutes.

Then they were in about 4000 ml of a solution of Sifted sodium alginate in deionized water. These Solution was made by adding 30 g of sodium alginate in  1000 g of deionized water were dissolved and the obtained solution by adding further deionized Water to a solution containing 0.75% by weight of alginate was diluted. The pearls remained under about 15 minutes gently stir with a hanging stirrer in the alginate solution. During this time calcium ions diffused from the Inside the pearls to the surface and caused the Crosslinking of alginate to form a water soluble, ion-permeable gel shell.

The solution was worked up with about 2000 ml deionized water. The pearls were on finally sieved, washed with deionized water, for post-crosslinking for 20 to 30 minutes in a stirred, 2nd % CaCl solution dipped and were then for the further Ready to use.

3.2. Coating with a shell made of alginic acid gel

The example 3.1. was repeated as a crosslink however, HCl was used as a medium. Have been soaked 150 g of the beads obtained in Example 1 or 2 in a 1-normal, aqueous hydrochloric acid immersed. After sieving into the same as under 3.1. described alginate Solution causes the protons of the acid to diffuse Formation of the gel envelope.

The coated gel beads were worked up Sieving and washing immersed in 1 normal hydrochloric acid, washed again after 20 minutes and were then for the Ready to use.

Example 4 One-step production of gel pearls with water soluble ion permeable shell

A solution A and one were separated from each other Solution B prepared.

Solution A was an emulsion containing 1.5% by weight sodium alginate (Protanal LF 20/60) in 88.4% by weight deionized Water 10% by weight of a mixture of tri-iso-octylamine and aliphatic hydrocarbon mixture (Shell Sol T®) in Ratio 1: 5 and 0.1% by weight of an emulsifier (Emulso gene L®, Hoechst AG) contained.

Solution B was a 3.3 wt% solution of Sodium alginate in deionized water.

Solution A was the central opening of a two-substance nozzle fed; around this central opening was another Opening arranged concentrically. She was given solution B fed. The flow rate of Solution A: Solution B was on a ratio of about 2: 3 is set. It emerged Drop in a stirred, approximately 2% CaC1, solution were dropped. To complete the networking the resulting balls were used for about 45 minutes hanging stirrer stirred crosslinking solution and then sieved, washed with deionized water and dried. The pearls obtained were immediately available to Ver intended purpose.

Example 5 Single-stage production of the coated agent, ent holding a thermally crosslinked gel as the core material and an initially ionotropically cross-linked shell, which kung is transferred into a covalently cross-linked envelope 5.1. The complexing agent contains emulsified Particles 5.1.a Preparation of the emulsion

200 ml of a 2 wt .-% aqueous agar solution were heated to about 60 ° C and there until the final Vernet tongue tempered. About 4 g were initially added to this solution Given sodium tripolyphosphate. Then you gave Car boxymethylcellulose too to increase the viscosity of the solution increase. The amount of this viscosity increasing agent was dimensioned so that in the subsequent networking in Crosslinker bath does not break up the dripped, finished emulsion ran, but the teardrop shape was preserved. For this were about 3 g carboxymethyl cellulose necessary. The solution was then adjusted to a pH of about 5 with phosphoric acid adjusted and by means of a turbo stirrer (Ultra-Turrax) about 40 g of a solution of 8 g di-iso-tridecylamiln in 32 g aliphatic hydrocarbon mixture (Shell Sol T®) emulsified in kerosene, the emulsion using 0.5 g an emulsifier (Emulsogen L®, Hoechst AG) stabilized has been. The finished emulsion was used until further processing tempered to about 60 ° C.

5.1.b Manufacture of the cross-linking bath

In 1000 ml of a 1% by weight aqueous glacial acetic acid solution (pH: about 4) 10 g of chitosan were dissolved. For this was de a high-viscosity chitosan from Chungai Boyeki, Düsseldorf used. The 1% by weight chitosan obtained Solution was then watered to a level diluted by 0.3% by weight of chitosan. The crosslinker bath existed from 2000 ml of this 0.3% by weight chitosan solution and was tempered to 15 ° C.

5.1.c Production of the particles

The emulsion of the nonionic precursor of the agent, which was heated to 60 ° C., was then added dropwise to the crosslinker bath, which was heated to 15 ° C. The beads formed in this way remained in the solution for about 15 minutes, were sieved off and kept in a buffer solution for 5 hours (0.1N Na ₂ HPO ₄ in water, pH value: about 8).

The beads were then sieved again and to reinforce the shell in a second crosslinking bath dives. This second crosslinker bath was one made of baking soda lye adjusted to a pH of about 7 Mix about 15 g glutardialdehyde with 500 ml water obtained solution. After 30 minutes in this second ver the pearls were sieved and washed. Then the beads are not used to transfer the ionic agent precursor in the ionic agent in 1-normal Hydrochloric acid dipped and were then ready for use.

5.2. Suspended containing the ionic agent Particles

About 30 g of a solid, which accordingly Example 1 had been prepared and as an agent precursor 10 g tri-iso-octylamine coupled to 20 g hydrophobized Contained silica airgel (Aerosil R 805, Degussa AG) finely powdered and suspended in an analogue before suspending Example 5.1.a Suspen prepared aqueous agar solution dated and the suspension obtained as in Example 5.1.c described in a crosslinker bath obtained according to 5.1.b. brought and processed.

Example 6 Use of the agent produced according to the invention for the separation of the chlorometalate complexes from platinum (IV) and rhodium (III)

• A) Were used with an ion permeable sheath provided gel particles, which according to Example 2.1. produced and according to Example 3.2. with an alginic acid gel envelope had been coated. 10 g of these coated gel beads were in 100 ml of a 10% aqueous hydrochloric acid solution, containing 220 mg / l platinum and 23 mg / l rhodium give. The solution with the gel beads was for 30 minutes  shaken, the beads then sieved and the Residual concentration of precious metal in the aqueous solution certainly. The platinum content was only 15 mg / l Rhodium content 21 mg / l. The extraction of 93% of the platinum and 9% of the rhodium content.
• B) This time gel particles were used, which according to Example 2.2. prepared and according to Example 3.2. With an ion-permeable shell had been coated. 10 g these coated gel beads were placed in an aqueous, Given 10% hydrochloric acid, the 90.1 mg / l platinum (IV) and 17.4 mg / l rhodium (III) contained. The extraction rate after 30 minutes was about 50% for the chloro complex Platinum (IV) and approx. 10% for the chloro complex of rhodium (III).

To regenerate the beads loaded with the chlorometalates, they were introduced into a 1-normal sodium hydroxide solution which contained about 0.2% by weight of CaCl ₂ .

The precious metal-containing sodium hydroxide solution became Extraction of the precious metal content worked up.

Example 7 Use of the agent produced according to the invention for the separation of dichromate anions

Were used according to example 2.3. manufactured Gel beads, which according to Example 3.2. with an envelope Alginic acid gel had been coated.

An aqueous solution which had a pH of 1.2 and contained 100 mg / l Cr ₂ O ₇ ^{2 was passed} through 940 g of these gel beads. The flow rate of the aqueous solution was 40 ml / min. The dichromate content in the outflow of the aqueous solution was still 18.8 mg / l. 81% of the dichromate content was thus separated off.

Claims (21)

1. For the selective separation of metal complex anions from aqueous solutions suitable particulate Agent containing an ionic, non-polymeric, with Metal complex anions disper an agent forming an ion pair gates in a continuous aqueous phase, which in embedded and / or part of a hydrophilic gel is hydrophilic gel and / or from a water-insoluble, ion-permeable shell is surrounded. 2. Composition according to claim 2, characterized in that the ion pair-forming agent is selected from compounds of the general formula (I) (R¹R²NH₂) ⁺X ^- (I) and the general formula (II), (R¹R²R³NH) ⁺X ^- (II) wherein R ¹ , R ² and R ^{3 can be the} same or different and can independently mean:
Alkyl with 6 to 20 carbon atoms; branched alkyl having 6 to 20 C atoms, optionally substituted by OR ⁴ or SR ⁴ alkyl, where R ^{4 is} alkyl having 1 or 10 C atoms; Aryl, especially phenyl, optionally substituted with 1 to 3 lower alkyl groups, especially methyl;
and X ^- organic or inorganic acid residues, preferably as sulfate nitrate or halide, in particular chloride. 3. Means according to claim 1 or 2, characterized records that the aqueous phase is embedded in a gel or is part of a gel. 4. Means according to claim 3, characterized in that the gel is a hydrophilic cross-linked organic gel is. 5. Particulate agent according to claim 3 or 4, characterized in that it is essentially a water-insoluble, ion-permeable shell is surrounded. 6. Composition according to claim 5, characterized in that the continuous aqueous phase into a thermal cross-linked hydrophilic organic gel embedded and of a covalently cross-linked hydrophilic organic gel is enveloped. 7. Composition according to one of the preceding claims, characterized in that the agent in a water immiscible solvent is present in solution. 8. Agent according to one of the preceding claims, characterized in that it is coupled to the agent contains a hydrophobized carrier material. 9. Composition according to one of the preceding claims, characterized in that it consists of particles with a Diameter from about 0.1 mm to about 6 mm. 10. Agent according to one of the preceding claims, characterized in that there is about 0.5 to 30 wt .-% gel agent, about 1 to 50% by weight of agent, 0 to about 40% by weight  preferably 10 to 30% by weight, water-insoluble solution 0 to about 10% by weight of conventional auxiliaries and contains about 40 to 90 wt .-% water. 11. Use of the particulate agent after one of claims 1 to 10 for the separation of Metallkom plexanions from aqueous solutions. 12. A process for the preparation of a particulate agent suitable for the selective separation of metal complex anions from aqueous solutions, comprising an ionic, non-polymeric agent which forms an ion pair with metal complex anions, dispersed in a continuous aqueous phase which is embedded in a hydrophilic gel and / or constituent is a hydrophilic gel and / or is surrounded by a water-insoluble, ion-permeable shell, characterized in that

• a) the ionic agent or a non-ionic precursor of the agent is dispersed in an aqueous phase which contains a crosslinking agent, a precursor of a hydrophilic gel which can be crosslinked by a crosslinking agent or a thermally crosslinkable precursor of a hydrophilic gel
• b) to form particles from the dispersion obtained under a)
  • b1) the dispersion containing a crosslinking agent for encapsulation with an essentially water-insoluble, ion-permeable shell is introduced into a solution which contains a gel precursor of a water-insoluble, ion-permeable shell material which can be crosslinked by the crosslinking agent, or
  • b2) which introduces a heat-crosslinkable or heat-crosslinkable precursor of a hydrophilic gel to form discrete gel particles into a liquid phase which has a temperature which is sufficiently high for the thermal crosslinking of the gel precursor, or a sufficiently low temperature for the thermal crosslinking of the gel precursor Temperature, or
  • b3) which introduces a dispersion containing a crosslinking agent precursor of a hydrophilic gel into a solution containing the crosslinking agent or incorporates the crosslinking agent into the dispersion
• c) if a non-ionic precursor of the agent has been used in stage a), this is converted into the ionic agent

and if necessary

• d) the particles obtained in stage b1), b2), b3) or c) are coated with a substantially water-insoluble ion-permeable shell and / or a shell surrounding the particles made of a non-covalently crosslinked amino group-containing shell material is reinforced by additional covalent crosslinking.

13. The method according to claim 12, characterized in net that in step d) the particles with a vernetzba Ren gel precursor of the coating material contacted and the ver wettable gel precursor cross-linked. 14. The method according to claim 12, characterized in net that a dispersion obtained in step a), which contains a crosslinkable precursor of a gel, and one second liquid, which is a crosslinkable gel precursor contains a water-insoluble, ion-permeable shell, enters together into a third liquid such that the dispersion is surrounded by the second liquid.   15. The method according to claim 14, characterized in net that the dispersion obtained in step a) by enters a nozzle which of the second liquid feeding pipe is surrounded. 16. The method according to claim 12, characterized in net that a dispersion obtained in step a), which a thermally crosslinkable precursor of the in the particle forming gel and a crosslinking agent which ionotro pe crosslinkable gel precursors are able to crosslink into a sufficiently cold or sufficiently warm aqueous solution an ionotropically crosslinkable gel precursor of the coating material enters. 17. The method according to claim 16, characterized in net that as a thermally crosslinkable precursor of the in Gels to be formed are a crosslinkable by cold Prepress is used. 18. The method according to claim 16 or 17, characterized ge indicates that an anionic as crosslinking agent Crosslinking agent and as an ionotropically crosslinkable gel precursor of the shell material is an amino sugar-containing polysaccharide is used. 19. The method according to claim 12 to 18, characterized ge indicates that one contains amino groups, not covalently cross-linked shell material to reinforce the shell with contacted a crosslinking agent which amino groups is able to covalently network. 20. The method according to claim 12, characterized in net that in stage a) a non-ionic precursor of Agent used, preferably dissolved in a water soluble solvent or coupled to a hydro phobized carrier material.