WO1992017403A1

WO1992017403A1 - Support bonded polyalkylene-polyamine-poly(carboxylic acid) and extraction of metal ions therewith

Info

Publication number: WO1992017403A1
Application number: PCT/US1992/002730
Authority: WO
Inventors: Ronald L. Bruening; Bryon J. Tarbet; Krzysztof E. Krakowiak; Jerald S. Bradshaw; Reed M. Izatt
Original assignee: Brigham Young University
Priority date: 1991-04-05
Filing date: 1992-04-03
Publication date: 1992-10-15
Also published as: AU1742092A

Abstract

A method for the removal and concentration of desired ions from a source solution which may contain larger concentrations of other ions including H+ comprises bringing the source solution into contact with a compound comprising a polyalkylene-polyamine-polycarboxylic acid-containing ligand covalently bonded through an organic spacer silicon grouping to a solid inorganic support. The polyalkylene-polyamine-polycarboxylic acid portion(s) of the compound has an affinity for the desired ions to form a complex thereby removing the desired ions from the source solution. The desired ions are removed from the compound by contacting the compound with a much smaller volume of a receiving solution having a greater affinity for the desired ions than does the polyalkylene-polyamine-polycarboxylic acid ligand portion of the compound. The concentrated ions thus removed may be recovered by known methods. The process is useful in removing desired or unwanted ions from copper electrolyte, nuclear waste streams, and other industrial or environmental streams. The invention is also drawn to the polyalkylene-polyamine-polycarboxylic acid-containing ligands covalently bonded through a spacer grouping to a hydrophilic inorganic solid support material.

Description

SUPPORT BONDED POLYALKYLENE-POLYAMINE-POLY(CARBOXYLIC ACID) AND EXTRACTION OF METAL IONS THEREWITH.

FIELD OF THE INVENTION

This invention relates to polyalkylene-polyamine- polycarboxylic acid-containing hydrocarbons covalently bonded to inorganic solid supports and to a process for removing and concentrating certain desired ions, from solutions wherein such ions may be admixed with other ions which may be present in much higher concentrations by the use of such polyalkylene-polyamine-polycarboxylic acid-solid supported materials. More particularly-, this invention relates to a process for removing such ions from an admixture with others in solution by forming a complex of the desired ions with compounds composed of a polyalkylene-polyamine-polycarboxylic acid moiety covalently bonded to an inorganic matrix by flowing such solutions through a column packed with such polyalkylene-polyamine-polycarboxylic acid-solid supported materials and then breaking the complex of the desired ion from the compounds to which such ion has become attached by flowing a receiving liquid in much smaller volume than the volume of solution passed through the column to remove and concentrate the desired ions in solution in the receiving liquid. The concentrated ions thus removed may then be recovered by known methods.

BACKGROUND OF THE INVENTION Effective methods for the recovery and/or separation of particular ions such as lanthanide ions, i.e. europium, gadolinium and samarium; bismuth ion and transition metal ions such as iron and copper from solutions thereof admixed with chelating agents and/or other ions which may be present represent a real need in modern technology. As specific examples, efficient and economical separation of (1) Bi from BjSO,, containing Cu electrolyte; (2) separation of Am and Cm from the lanthanides after initial partitioning from nuclear waste; and (3) separation of individual lanthanides from each other for a variety of uses all represent real separation needs with presently unsatisfactory technologies for their accomplishment. These ions are often present at low concentrations in solutions containing other ions at much greater concentrations. Hence, there is a real need for a process to selectively concentrate and recover these ions.

It is known that polyamino acids, e.g., ethylenedinitrilotetraacetic acid (EDTA) , diethylenetrinitrilo pentaacetic acid (DTPA) , and triethylenetetranitrilohexaacetic acid (TTHA) are capable of selectively forming stable complexes with a variety of cations as described in a book by A.E. Martell et al., Critical Stability Constants Vol . 1: Amino Acids . Plenum Press, New York , 1974, pp. 86-293. It has also been suggested by K. Ohshima et al., "Preconcentrations of Trace Metal Ions by Compleκation with Ethylendiaminetri-acetate-Bonded Silica Gel" , Analytical Sciences, vol. 2, pp. 131-135 (1986)that when EDTA is bound to silica gel it retains the ability to form stable complexes with many ions. However, EDTA bound to silica gel is incapable of binding bismuth at low pH. Also, Martell et al., supra, states that EDTA shows little selectivity among rare earth cations. Silica gel bound EDTA is also ineffective in removing ions from solutions of co plexing agents such as EDTA. According to Martel et al. , longer amino acids, such as DTPA and TTHA, are known to form complexes which are more stable than the corresponding EDTA complexes. The Martell et al. reference specifically quantitates (1) the large increase in the Bi³⁺ interaction strength in going from EDTA to DTPA; (2) the increase in Am ³⁺ and Cm ³⁺ selectivity over the trivalent lanthanides in going from EDTA to DTPA and TTHA; (3) the increase in individual trivalent lanthanide selectivities with the amino acids longer than EDTA; and (4) the significant increase in interaction strength with the longer amino acids for Sc(III) , Y(III) , the trivalent lanthanides, Am(III) , CM(III), other trivalent actinides, several tetravalent actinides, Mn(II) , Fe(II), Co(II) , Ni(II), Cu(II), Fe(III), Zr(IV) , Hf(IV), Zn(II) , Cd(II) , Hg(II) , Sn(II), Al(III), Ga(III), In(III) , Tl(III) and Sb(III) . However these longer amino acids are somewhat expensive and have not heretofore been available in a form which will permit their use in an economical manner for the removal and concentration of certain cations from solution. The products and processes described in the present invention accomplishes this objective. The unique complexing properties of the polyalkylene- polyamine-polycarboxylic acid-containing Iigands as attached to appropriate inorganic solid supports is the subject of the present invention. SUMMARY OF THE INVENTION

The compounds of the present invention comprise suitable polyalkylene-polyamine-polycarboxylic acid- containing Iigands which are covalently bonded through a spacer grouping to a silicon atom and further covalently bonded to a solid support and are represented by the following formula 1:

M rix-O- (Formula 1)

where Matrix is selected from the group consisting of sand or silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide; Y and Z are members selected from the group consisting of Cl, O-matrix, lower alkoxy,, lower alkyl and halogenated lower alkyl; with lower alkoxy being preferred and methoxy and ethoxy being particularly preferred; x and y are integers of 0 or 1 with the proviso that when x is 0 y is 1;

R¹ is a member selected from the group consisting of OH, H, lower alkyl, or aryl; with OH being preferred; R² is a member selected from the group consisting of H, OH, lower alkyl, lower aryl or, when y is 0, -(CH₂)₈COOH; with H and -(CH₂)_εC00H being preferred; o

R³ is a member selected from the group consisting of -NHC-

Λ,

-COOH, -N-[(CH₂){-COOH]2 or -HH₂

R is a member selected from the group consisting of

0 O -(CH₂)_tNHC-A ; -C-A and

A is

-(

)_jCOOH a and i are each integers which may vary from 2 to 10 r is an integer which may vary from 0 to 10 b, d, e, f, g, h, j, k, 1, m, q, t, u, v and w are each integers which may vary from 1 to 10 with integers of 1 or 2 being preferred; with the proviso that the combination of R², R³ and R⁴ must contain a minimum of four -(CH₂)_zCOOH moieties attached to pendant nitrogens where z is an integer which may vary from 1 to 10 and is selected from f, g, h, k, 1, g and u.

When Y and Z are other than O-Matrix they are functionally classified as leaving groups, i.e. groups attached to the silicon atom which, when reacted with an O-Matrix material, may leave or be replaced by the O- Matrix. If any such functional leaving groups are left over after reacting with a silicon containing grouping with the solid hydrophilic matrix or support, these groups will have no direct function in the interaction between the desired ion and the polyalkylene-polya ine- polycarboxylic acid ligand-attached to the matrix or solid support. The matrix or solid support, which terms may be used interchangeably, is a member selected from the group consisting of silica, zirconia, titania, alumina, nickel oxide or other hydrophilic inorganic supports and mixtures thereof. Lower alkyl or alkoxy means a 1-6 carbon member alkyl or alkoxy group which may be substituted or unsubstituted, straight or branched chain. By substituted is meant by groups such as Cl, Br, I, N0₂ and the like. As stated previously, when X and Y are not O-Matrix they are preferably lower alkoxy with methoxy and ethoxy being preferred. The polyalkylene-polyamine-polycarboxylic acid Iigands covalently bonded to solid supports as shown in Formula 1 are characterized by high selectivity for and removal of desired ions or groups of desired ions such as Bi³⁺, certain lanthanide ions, and certain transition metal ions present at low concentrations from the source phase containing a mixture of these metal ions with the ions one does not desire to remove present in much greater concentrations in the solution and any complexing agents in a separation device such as a column through which the solution is flowed. The process of selectively removing and concentrating the desired ion(s) is characterized by the ability to quantitatively complex from a larger volume of solution the desired ion(s) when they are present at low concentrations. The desired ions are recovered from the separation column by flowing through it a small volume of a receiving phase which contains a solubilized reagent which need not be selective, but which will strip the desired ions from the ligand quantitatively. The recovery of the desired metal ions from the receiving phase is easily accomplished by well known procedures.

DETAILED DESCRIPTION OF THE INVENTION As summarized above, the present invention is drawn to novel polyalkylene-polyamine-polycarboxylic acid- containing hydrocarbon Iigands covalently bound through a spacer to a silicon moiety and further attached to a solid matrix or support, to form the novel compounds of Formula 1. The invention is also drawn to the concentration and removal of certain desired ions such as Bi³⁺, certain lanthanide ions, and certain transition metal ions, from other ions. For example, effective methods of recovery and/or separation of metal ions from other metal ions, such as (1) the separation of lanthanide ions from each other, (2) separation of bismuth from copper electrolytes, and (3) recovery and/or separation of cations from chelating solutions such as the removal of transition metal cations from solutions containing simple amino acids such as NTA or EDTA represent a real need for which there is no economically feasible and established procedures. Such solutions from which such ions are to be concentrated and/or recovered are referred to herein as "source solutions." In many instances the concentration of desired ions in the source solutions will be much less than the concentration of other ions from which they are to be separated.

The concentration of desired ions is accomplished by forming a complex of the desired ions with a polyalkylene-polyamine-polycarboxylic acid ligand bound through an appropriate spacer to a matrix or solid support compound shown in Formula 1 by flowing a source solution containing the desired ions through a column packed with a polyalkylene-polyamine-polycarboxylic acid ligand-solid support compound to attract and bind the desired ions to the ligand portion of such compound and subsequently breaking the ligand compound-complex by flowing a receiving liquid in much smaller volume than the volume of source solution passed through the column to remove and concentrate the desired ions in the receiving liquid solution. The receiving liquid or recovery solution forms a stronger complex with the desired ions than does the polyalkylene-polyamine- polycarboxylic acid ligand and thus the desired ions are quantitatively stripped from the polyalkylene-polyamine- polycarboxylic acid ligand bound through a spacer to the solid support matrix in concentrated form in the receiving solution. The recovery of desired ions from the receiving liquid is accomplished by known methods.

The polyalkylene-polyamine-polycarboxylic acid- containing Iigands, as represented by Formula 1, may be prepared by various methods which are illustrated in the examples which follow. For example in one method the silane containing spacer grouping which links the polyalkylene-polyamine-polycarboxylic acid ligand to the solid support matrix, may first be bound to the matrix followed by reacting that product with the polyalkylene- polyamine-polycarboxylic acid. In a second method a polyalkylene-polyamine may first be reacted with the spacer grouping to form an intermediate product which is carboxyalkylated to complete the polyalkylene-polyamine- polycarboxylic acid ligand which, in turn, is reacted with the solid support matrix. In a third method a polyalkylenepolya ine is reacted with a spacer grouping which is then reacted with a solid support matrix followed by reacting with a polyalkylene-polyamine- polycarboxylic acid. These methods and others will be apparent to those skilled in the art by the following examples. Example 1

In this example 50 g of 35-60 mesh silica particles were first reacted with an amine containing silane such as 3-aminopropyltriethoxysilane (4.42 g 0.02 mmol) in a solvent such as toluene at a temperature of 50-60^βC for 18 hours. The silica gel was collected by filtration and dried. This silica gel was further reacted by treating it as follows. First, the treated gel was suspended in a 500 mL 3-necked flask with a mechanical stirrer and dimethylformamide as the solvent. This was followed by diethylenetriamine-pentaacetic acid anhydride (Aldrich Chemical) , dicyclohexylcarbodiimide (Aldrich) , and hydroxybenzotriazole (Aldrich) in equimolar amounts corresponding to the amount of immobilized aminopropylsilane. After reacting overnight at R.T., the mixture was heated for 3 hours at 40-60°C and then the solvent was decanted and the gel was washed with water 3 times and then with methanol twice. The final product was isolated by suction filtration and vacuum dried. This product corresponds to Formula 1 wherein Matrix is silica gel, Y and Z are OCH₂CH₃, a is 3, x is 0, R² is H, y is 1, d is 1, e is 1, R³ is COOH, and R⁴ is

-(

) COOH wherein r is 1, m is 2, q is 1, t is 2, u is 1 and v is 1.

Example 2 In this example, an alternative method of preparing diethylenetria ine-pentaacetic acid (DTPA) immobilized on silica gel was employed as follows. First, diethylenetriamineand3-glycidoxypropyltrimethoxysilane were reacted together in methanol overnight at R.T. The mixture was stirred with a mechanical stirring device, heated to 80-90^βC, and the sodium salt of bromoacetic acid (Aldrich) was added slowly. Portions of NaOH were added to keep the pH above 13 (caution exothermic) . The amount of bromoacetic acid added was in large excess to ensure that all the nitrogen atoms were carboxymethylated. The mixture was then neutralized, and the silica gel was added (35-60 mesh) , and allowed to react overnight. The product was filtered, washed and dried. This method of preparation affords a product similar to that obtained in Example 1 but with lower usable capacity.

This product corresponds to Formula 1 wherein Matrix is silica gel, Y and Z are 0CH₃, a is 3, x is 1, b is 1, R¹ is OH, R² is CH₂COOH, y is 0, d is 2, e is 1, R³ is COOH, and R⁴ is

-(

wherein r is 0, t is 2, u is 1 and v is 1. Example 3

In this example, an alternative method of preparing diethylenetriamine-pentaacetic acid (DTPA) immobilized on silica gel was employed with the intent to increase the capacity of the silica gel. The procedure was carried out as follows. First, tris(2-aminoethylamine) and 3-glycidoxypropyltrimethoxysilane were reacted together in a 1.1:1 ratio in toluene overnight at room temperature (R.T.). To the stirred mixture was added the silica gel and the mixture was heated at 60-75 °C overnight. The silica gel was filtered and dried and used as in the first example to prepare DTPA immobilized on silica gel. This was done by suspending the treated gel in a 500 mL 3-necked flask with a mechanical stirrer with dimethylformamide as the solvent. This was followed, as in Example 1, by the addition of diethylenetriamine-pentaacetic acid anhydride, dicyclohexylcarbodiimide, and hydroxybenzotriazole in equimolar amounts corresponding to the amount of tris(2- aminoethylamine) which was reacted with glycidoxypropyltrimethoxysilane and immobilized to the silica gel. This was to take advantage of the two primary amine sites available. After reacting overnight at R.T., the mixture was heated for 3 hours at 40-60°C and then the solvent was decanted and the gel was washed with water 3 times and then with methanol twice. The final product was isolated by suction filtration and vacuum dried.

This product corresponds to Formula 1 wherein Matrix is silica gel, Y and Z are OCH₃, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2,

O 0

R³ is NH₂ or -NHC-A, and R⁴ is -(CH,)_BNHC-A with A having the formula

-(

wherein w is 2, i is 2, g is 1 (first occurrence) and g is 2 (second occurrence), h is 1, j is 2, k is 1 and 1 is 1. The moiety represented by R³ depends on the amount of diethylenetriamine-pentaacetic acid anhydride reacted with the pendant amino groups. Example 4 In this example, triethylenetetraminehexaacetic acid (TTHA) was immobilized on silica gel as in the first example. The conditions used were the same except in place of diethylenetriaminepentaacetic acid anhydride, the anhydride of TTHA was used. This product corresponds to Formula 1 wherein Matrix is silica gel, Y and Z are OCH₂CH₃, a is 3, x is 0, R² is H, y is 1, d is 1, e is 1, R³ is COOH, and R⁴ is

wherein r is^"2, m is 2, q is 1, t is 2, u is 1 and v is 1.

Example 5

The filtered and dried silica gel intermediate product obtained in Example 3 is reacted with the sodium salt of bromoacetic acid (Aldrich) in the manner described in Example 2 to carboxymethylate all nitrogen atoms which produces a product corresponding to Formula 1 wherein Matrix is silica gel, Y and Z are 0CH₃, a is 3, x is 1, b is 1, R¹ is OH, R² is CH₂COOH, y is 0, d is 2, e is 2, R³ is -N-[(CH₂)_f-COOH]₂ where f is 1, and R⁴ is

wherein r is 0, t is 2, u is 1 and v is 1. Example 6

The intermediate product obtained in Example 2 from the reaction of, 3-glycidoxypropyltrimethoxysilane and diethylenetriamine is reacted with silica gel in the manner described above. The silica gel product is filtered and dried and then reacted with diethylenetriamine-pentaacetic acid (DTPA) anhydride in a molar ratio of two moles of DTPA per mole of diethylenetriamine to produce a product according to Formula 1 wherein Matrix is silica gel, Y and Z are 0CH₃, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2, R³ is

0 O -NHC II-A and R _Λ ⁴ is -CII-A with A, both occurrences, having the formula

wherein i is 2, g is 1 (first occurrence) and g is 2 (second occurrence), h is 1, j is 2, k is 1 and 1 is 1. Example 7

The product of Example 3 is modified by the addition of one mole each of diethylenetria ine- pentaacetic acid (DTPA) anhydride and triethylenetetramine-hexaacetic acid (TTHA) anhydride to produce a product according to Formula 1 wherein Matrix is silica gel, Y and Z are OCH₃, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2, R³ is 0

-NHC II-A with A, having the formula

COOH COOH I I

(CH₂)_h (CH₂)_k

-( (CH₂)_fN),-(CH₂)_rN-(CH₂),-COOH wherein i is 2, g is 1 (first occurrence) and g is 2 (second occurrence), h is 1, j is 2, k is 1, 1 is 1; and R⁴ is

0 -(CH₂),NHC-A with A having the formula

-(

wherein w is 2, i is 3, g is 1 (first occurrence) and g is 2 (second and third occurrence), h is 1, j is 2, k is

1 and 1 is 1.

From the above examples it would be evident to one skilled in the art to prepare myriad polyalkylene- polyamine-polycarboxylic acids which fall within the scope of Formula 1.

Onepreferredpolyalkylene-polyamine-polycarboxylic acid grouping for use in the present invention are those wherein X and Y are lower alkoxy, a is 3, x is 0, R² is

H, y is 1, d is 1, e is 1, R³ is COOH and R⁴ is

wherein r is either 1 or 2, m is 2, q is 1, t is 2, u is 1 and v is 1. The O-Matrix portion is not critical as long as it provides the proper support and can be any of the moieties mentioned above. These are products exemplified in Examples 1 and 4. Another preferred polyalkylene-polyamine-polycarboxylic acid grouping for use in the invention is where Y and Z are lower alkoxy, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2, R³ is selected from the group consisting of either

-NH₂ or --HHHHCC--AA or a mixture thereof,

and R' is

0 -(CH₂)₂NHC-A where in A, in each instance has the formula

-(

wherein i is either 2 or 3, g is 1 (first occurrence) and g is 2 (second and third occurrence) , h is 1, j is 2, k is 1 and 1 is 1. The process of selectively and quantitatively concentrating and removing a desired ion or group of desired ions present at low concentrations from a plurality of other undesired ions in a multiple ion source solution in which the undesired ions and other chelating agents may be present at much higher concentrations comprises bringing the multiple ion containing source solution into contact with a polyalkylene-polyamine-polycarboxylic acid ligand- containing solid supported compound as shown in Formula 1 which causes the desired ion(s) to complex with the polyalkylene-polyamine-polycarboxylic acid ligand portion of the compound and subsequently breaking or stripping the desired ion from the complex with a receiving solution which forms a stronger complex with the desired ions than does the polyalkylene-polyamine- polycarboxylic acid ligand or which forms a stronger complex with the polytetraalkylam onium or polytrialkylamine ligand. The receiving or recovery solution contains only the desired ions in a concentrated form.

The polyalkylene-polyamine-polycarboxylic acid ligand solid matrix support functions to attract the desired ions (DI) according to Formula 2: SS-O-Si-Spacer-L + DI > SS-0-Si-Spacer-L:DI

(Formula 2)

Where SS-O is the same as Matrix-0 in Formula 1. Si- Spacer- is the same as:

Y R¹

-Si-(CH₂)_a[(0CH₂CHCH₂)_b]_χ- in Formula 1,

Z and L is the same as:

in Formula 1.

Formula 2 is an abbreviated form of Formula 1 wherein SS stands for solid support, and L stands for a polyalkylene-polyamine-polycarboxylic acid containing ligand. DI stands for desired ion being removed.

Once the desired ions are bound to the polyalkylene-polyamine-polycarboxylic acid-containing ligand, they are subsequently separated by use of a smaller volume of a receiving liquid according to Formula 3:

SS-0-Si-Spacer-L:DI + receiving liquid >

SS-O-Si-Spacer-L + receiving liquid:DI (Formula 3)

The preferred embodiment disclosed herein involves carrying out the process by bringing a large volume of the source multiple ion solution, which may contain hydrogen ions and may also contain chelating agents, into contact with a polyalkylene-polya ine- polycarboxylic acid ligand-solid support compound of Formula 1 in a separation column through which the mixture is first flowed to complex the desired metal ions (DI) with the polyalkylene-polyamine-polycarboxylic acid ligand-solid support compound as indicated by Formula 3 above, followed by the flow through the column of a smaller volume of a receiving liquid, such as aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, thiourea, NH₄OH, Na₂S₂0₃, HI, HBr, Nal, ethylenediamine, Na₄EDTA, glycine, and others which form a stronger complex with the desired ion than does the polyalkylene-polyamine-polycarboxylic acid-containing ligand bound to the solid support or forms a stronger complex with the polyalkylene-polyamine-polycarboxylic acid-containing ligand bound to the solid support than does the desired ion. In this manner the desired ions are carried out of the column in a concentrated form in the receiving solution. The degree or amount of concentration will obviously depend upon the concentration of desired ions in the source solution and the volume of source solution to be treated. The specific receiving liquid being utilized will also be a factor. The receiving liquid does not have to be specific to the removal of the desired ions because no other ions will be complexed to the ligand. Generally speaking the concentration of desired ions in the receiving liquid will be from 20 to 1,000,000 times greater than in the source solution. Other equivalent apparatus may be used instead of a column, e.g., a slurry which is filtered which is then washed with a receiving liquid to break the complex and recover the desired ion(s) . The concentrated desired ions are then recovered from the receiving phase by known procedures. Illustrative of desired ions which have strong affinities for polyalkylene-polyamine-polycarboxylic acid-containing Iigands bound to solid supports are Bi(III), La(III), Ce(III), Pr(III) , Nd(III) , Pm(III) , Sm(III), Eu(III), Gd(III) , Tb(III) , Dy(III) , Ho(III), Er(III), Tm(III), Yb(III) , Lu(III) , Am(III) , Cm(III) , Zr(IV), Hf(IV), Sb(III), Fe(III), Co(III) , Mn(II) , Fe(II), Co(II), Ni(II), Cu(II), Zn(II) , Cd(II) , Hg(II), Pd(II), Pb(II), Y(III) , Sc(III), Pu(IV), U(VI) , Th(IV) , Al(III), Ga(III), In(III), Tl(III), and Sn(IV) . This listing of preferred ions is not comprehensive and is intended only to show the types of preferred ions which may be bound to polyalkylene-polyamine-polycarboxylic acid-containing Iigands attached to solid supports in the manner described above. The affinity of the ligand to the ions will obviously vary depending upon the ion and the ligand configuration. Hence it is possible that, even in the above listing, those ions having the stronger affinity for the ligand will be selectively removed from other ions in the listing which have a weaker affinity for the particular ligand. Hence, by proper choice of Iigands and makeup of the source solution it is possible to separate and concentrate one desired ion from another.

The process of the invention is particularly adaptable to the removal of Bi³⁺ ions from source solutions which may additionally contain H⁺ ions and one or more ions selected from the group Cu²⁺, SO^, HS0₄", Ni²⁺ and Sb³⁺. The source solution will consist of from up to 3 M H₂S0₄ or HN0₃ and the receiving liquid for removing the Bi³⁺ bound to the ligand will be an acid which may be at least 6 M H₂S0₄, 3 M HC1 or 5 M HN0₃.

In addtion to the ions mentioned above, the source solutions may also contain anions such as NTA^3*, EDTA^3", oxalate²", acetate¹", and citrate^3* and mixtures thereof. Besides bismuth, other desired ions which may be separated on a preferred basis are (1) Am³⁺ and Cm³⁺, (2) Zr⁺ and Hf^44" and (3) La³⁺, Ce³⁺, Pr³*, Nd³⁺, Pm³⁺, Sm³⁺, Eu³⁺, Gd³⁺ and Tb³⁺ and mixtures thereof. Removal of Desired Molecules With

Liσand-Matrix Compounds The following examples demonstrate how the polyalkylene-polyamine-polycarboxylic acid-containing ligand bound to a solid support compound of Formula 1 may be used to concentrate and remove desired ions. The polyalkylene-polyamine-polycarboxylic acid ligand containing solid support compound is placed in a column. An aqueous source solution containing the desired ion or ions, in a mixture of other ions and/or chelating agents which may be in a much greater concentration, is passed through the column. The flow rate for the solution may be increased by applying pressure with a pump on the top or bottom of the column or applying a vacuum in the receiving vessel. After the source solution has passed through the column, a much smaller volume of a recovery solution, i.e. an aqueous solution, which has a stronger affinity for the desired ions than does the polyalkylene-polyamine-polycarboxylic acid- containing ligand, is passed through the column. This receiving solution contains only the desired ion(s) in a concentrated form for subsequent recovery. Suitable receiving solutions can be selected from the group consisting of HN0₃, HC1, HBr, H₂S0₄, thiourea, Nal, HI, NH₄OH, ethylenediamine, Na₄EDTA, glycine and mixtures thereof. The preceding listing is exemplary and other receiving solutions may also be utilized, the only limitation being their ability to function to remove the desired ions from the polyalkylene-polyamine- polycarboxyliσ acid-containing ligand.

The following examples of separations and recoveries of ions by the inorganic support-bound polyalkylene-polyamine-polyσarboxylic acid-containing Iigands which were made as described in Examples 1 through 7 are given as illustrations. These examples are illustrative only, and are not comprehensive of the many separations of ions that are possible using the materials of Formula 1. Example 8

In this example, 5 g of the matrix supported polyalkylene-polyamino-polycarboxylic acid of Example 4 which is similar to unbound triethylenetetranitrilopentaacetic acid (TTPA) was placed in a column 5.1 cm. long having a diameter of 0.9 cm. A 250 mL "source" solution of approximately 100 ppm (parts per million) bismuth(III) ion in 2 M H₂S0₄, which also contained 1 M CuS0₄ and 0.1 M NiS0₄, was drawn through the column using a vacuum pump. The column was then washed with 25 mL of 2 M H₂S0₄. A 30 mL aqueous recovery solution of 8 M H₂S0₄ was then passed through the column. Analysis of the recovery solution by atomic absorption spectroscopy (AA) showed greater than 99% of the bismuth(III) ions originally in the 250 mL solution described above was in the 30 mL recovery solution and that no Copper(II) or Nickel(II) ion impurity could be detected in the recovery solution. Example 9 The procedure of Example 8 was repeated using 5 g of the matrix supported polyalkylene-polya ino- polycarboxylic acid of Example 1 which is similar to unbound diethylenetrinitrilotetraacetic acid (DTTA) . Virtually identical results were obtained. Example 10

In this example, 2 g of the matrix supported polyalkylene-polyamino-polycarboxylic acid of Example 1, which is similar to unbound diethylenetrinitrilotetraacetiσ acid (DTTA) was placed in a column. A source solution containing 0.001 M La(N0₃)₃, 0.001 M Eu(N0₃)_3/ 0.1 M sodium acetate, and 0.01 M acetic acid was drawn through the column using a vacuum pump until the La(III) and Eu(III) concentration entering and leaving the column was identical, e.g. the column was saturated. The column was then washed with 5 mL of H₂0. The column was then eluted with 25 mL of 6 M HC1 as a recovery solution. Analysis of the recovery solution by inductively coupled plasma (ICP) spectroscopy indicated that the 50-50 La:Eu mixture was converted to a 90:10 Eu:La mixture. This is an unusually high selectivity among lanthanide ions, particularly in light of the fact that Eu(III) has a slightly stronger complex with acetate than does La(III) . Hence, the acetate in the mixture is normally a hinderance to the performance of this separation. Example 11

In this example, 5 g of the matrix supported polyalkylene-polyamino-polycarboxylic acid of Example 1 which is similar to unbound diethylenetrinitrilotetraacetic acid (DTTA) was placed in a column. A 250 mL solution of approximately 50 pp (parts per million) Cu(II) ion in 0.5 M trisodiumnitrilotriacetic acid was drawn through the column using a vacuum pump. A 25 ml 6 M HC1 recovery solution was then passed through the column. Analysis of the recovery solution by atomic absorption spectroscopy showed greater than 99% of the Cu(II) ions in the original 250 mL were recovered. All of the experiments in the foregoing examples (Examples 8-11) were also carried out on the ethylenediaminetriacetate-bonded silica gels described by Ohshima, et.al.. supra. No detectable Bi(III) removal, a greatly reduced Eu(III) over La(III) separation, and poor Cu(II) removal were observed in these experiments. From these experiments, it will be appreciated that the polyalkylene-polyamino- polycarboxylic acid Iigands of Formula 1 bonded to a solid support such as silica gel of the present invention provide materials useful for the separation and concentration of lanthanides, some actinides, transition metal ions, and some post transition metal ions from mixtures of these ions with other metal ions and also in the presence of acids and/or complexing agents. The ions of interest can then be recovered from the concentrated recovery solution by standard techniques known in the science of these materials.

Although the invention has been described and illustrated by reference to certain specific silica gel- boundpolyalkylene-polyamino-polycarboxylic acid Iigands of Formula 1 and the process of using them, other analogs of these polyalkylene-polyamino-polycarboxylic acid Iigands falling within the scope of Formula 1 are also within the scope of the compounds and processes of the invention as defined in the following claims.

Claims

1. A method for the concentration and removal of desired ions from a source solution which comprises,

(a) bringing said source solution having a first volume into contact with a compound comprising a polyalkylene-polyamine-polycarboxylic acid-containing ligand covalently bonded to a solid inorganic support having the formula:

Matrix-0-

where Matrix is selected from the group consisting of sand or silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide; Y and Z are members selected from the group consisting of Cl, 0-matrix, lower alkoxy,, lower alkyl and halogenated lower alkyl; x and y are integers of 0 or 1 with the proviso that when x is 0 y is 1;

R¹ is a member selected from the group consisting of OH, H, lower alkyl, or aryl; R² is a member selected from the group consisting of H, OH, lower alkyl, lower aryl or, when y is 0, -(CH₂)-,C00H; R³ is a member selected from the group consisting 0 of-NHCII-A, -COOH, -N-[(CH₂)_f-COOHJ₂ or -NH,;

R⁴ is a member selected from the group consisting of

O o -(CH₂)_WNHC-A ; -C-A and

-(

A is

a and i are each integers which may vary from 2 to 10; r is an integer which may vary from 0 to 10; b, d, f, g, h, j, k, 1, m, q, t, u, v and w are each integers which may vary from 1 to 10; with the proviso that the combination of R², R³ and R⁴ must contain a minimum of four -(CH₂)_tCOOH moieties attached to pendant nitrogens where z is an integer which may vary from 1 to 10 and is selected from f, g, h, k, 1, q and u. said polyalkylene-polyamine-polycarboxylic acid containing ligand portion of said compound having an affinity for the desired ions to form a complex between said desired ions and said polyalkylene-polyamine- polycarboxylie acid containing ligand portion of said compound; (b) removing said source solution from contact with said compound to which said desired ions have been complexed; and (c) contacting said compound having said desired ions complexed thereto with a smaller volume of a receiving solution having a greater affinity for said desired ions than said compound or greater affinity for said compound than said desired ions thereby breaking said complex and recovering the desired ions in concentrated form in said smaller volume of said receiving solution.

2. A method according to Claim 1 wherein said polyalkylene-polyamine-polycarboxylic acid-containing ligand solid supported compound is contained in a packed column and wherein said source solution is first flowed through said packed column to allow the formation of a complex between said desired ions and said polyalkylene- polyamine-polycarboxylic acid-containing ligand portion of said compound followed by the breaking of said complex and removal of said desired ions from said packed column by flowing said smaller volume of said receiving solution through said packed column and recovering said receiving solution containing said desired ions in concentrated form.

3. A method according to claim 2 wherein the desired ion to be complexed is selected from the group of Bi(III), La(III), Ce(III) , Pr(III) , Nd(III) , Pm(III) , Sm(III), Eu(III), Gd(III), Tb(III) , Dy(III) , Ho(III), Er(III), Tm(III), Yb(III), Lu(III) , A (III) , Cm(III) , Zr(IV), Hf(IV), Sb(III), Fe(III), Co(III) , Mn(II) , Fe(II), Co(II), Ni(II), Cu(II) , Zn(II) , Cd(II) , Hg(II) , Pd(II), Pb(II), Y(III), Sc(III), Pu(IV), U(VI), Th(IV), Al(III), Ga(III), In(III), Tl(III), and Sn(IV) and mixtures thereof. 4. A method according to Claim 3 wherein X and Y are lower alkoxy, a is 3, x is 0, y is 1, d is 1, e is 1, R² is H, R³ is COOH and R⁴ is

)_rCOOH

wherein r is either 1 or 2, m is 2, q is 1, t is 2, u is 1 and v is 1.

5. A method according to Claim 3 wherein Y and Z are lower alkoxy, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2, R³ is selected from the group consisting of either

-NH, or - -ANHC--A or a mixture ther and R⁴ is

where in A, in each instance has the for uli

wherein i is either 2 or 3, g is 1 (first occurrence) and g is 2 (second and third occurrence) , h is 1, j is 2, k is 1 and 1 is 1.

6. A method according to claim 3 wherein the desired ion to be concentrated and removed is Bi(III) .

7. A method according to Claim 6 wherein the source solution contains H⁺ and additionally contains one or more ions selected from the group consisting of Cu²⁺, S0₄ ²", HS0₄", Ni⁺ and Sb³⁺. 8. A method according to Claim 7 wherein the acidic source solution contains an acid selected from the group consisting of from up to 3 M H₂S0₄ or HN0₃ and where the receiving liquid is also acidic containing an acid selected from the group consisting of at least 6 M H₂S0₄, at least 3 M HC1, or at least 5 M HN0₃.

9. A method according to Claim 3 wherein the desired ions to be concentrated and removed are selected from the group consisting of Am³⁺ and Cm³⁺ ions. 10. A method according to Claim 3 wherein the source solution contains ions selected from the group consisting of NTA³", EDTA³", oxalate²", acetate¹", and citrate³" and mixtures thereof.

11. A method according to Claim 3 wherein the desired ions to be concentrated and removed are selected from the group consisting of Zr⁺ and Hf⁴⁺.

12. A method according to Claim 11 wherein the source solution additionally contains H⁺ ions.

13. A method according to Claim 3 wherein the ion to be concentrated and removed is a member of the group consisting of La³⁺, Ce³⁺, Pr³*, Nd³⁺, Pm³⁺, Sm³⁺, Eu³⁺, Gd³⁺ and Tb³⁺ and mixtures thereof.

14. A method according to Claim 3 wherein the receiving solution is selected from the group consisting of H₂S0₄, Na₂S₂0₃, thiourea, HN0₃, HI, HBr, HC1, Nal, N^OH, ethylenediamine, Na₄EDTA, glycine and mixtures thereof.

15. A compound comprising a polyalkylene-polyamine- polycarboxylic acid covalently bonded to a solid inorganic support having the formula:

R³

R^l R²0 -έi-(CH₂)_a[(OCH₂C IHCH₂)_b]_χNI-(CII « )_e Matrix-0 )_J-(CH₂)_rNI-R^<

Z where Matrix is selected from the group consisting of sand or silica gel, glass, glass fibers, alumina, zirconia, titania or nickel oxide; Y and Z are members selected from the group consisting of Cl, O-matrix, lower alkoxy,, lower alkyl and halogenated lower alkyl; x and y are integers of 0 or 1 with the proviso that when x is 0 y is 1;

R¹ is a member selected from the group consisting of OH, H, lower alkyl, or aryl

R² is a member selected from the group consisting of H, OH, lower alkyl, lower aryl or, when y is 0, -(CH₂)_fCOOH;

R³ is a member selected from the group consisting o of -NHC-A, -COOH, -N-[ (CH₂)_f-COOH]₂ or -NH₂

R⁴ is a member selected from the group consisting of

0 0

-(CH₂)„NHCII-A ; -cII-A and

a and i are each integers which may vary from 2 to 10; r is an integer which may vary from 0 to 10 ; b, d, e, f, g, h, j, k, 1, m, q, t, u, v and w are each integers which may vary from 1 to 10; with the proviso that the combination of R², R³ and

R⁴ must contain a minimum of four -(CH₂)_rCOOH moieties attached to pendant nitrogens where z is an integer which may vary from 1 to 10 and is selected from f, g, h, k, 1, q and u. 16. A compound according to Claim 15 wherein X and Y are lower alkoxy, a is 3, x is 0, R² is H ,y is 1, d is 1, e is 1, R³ is COOH and R⁴ is

wherein r is either 1 or 2, m is 2, q is 1, t is 2, u is

1 and v is 1.

17. A compound according to Claim 16 wherein Y and

Z are methoxy or ethoxy and r is 1. 18. A compound according to Claim 16 wherein Y and

Z are methoxy or ethoxy and r is 1.

19. A compound according to Claim 15 wherein Y and

Z are lower alkoxy, a is 3, x is 1, b is 1, R¹ is OH, R² is H, y is 0, d is 2, e is 2, R³ is selected from the group consisting of either

0

-NH₂ or -NHC-A or a mixture: thereof,

and R⁴ is

0 -(CH₂)₂NHC-A wherein A, in each instance has the formula

-(

wherein i is either 2 or 3, g is l (first occurrence) and g is 2 (second and third occurrence), h is 1, j is 2, k is 1 and 1 is l. 29 20. A compound according to Claim 19 wherein

R³ is -NH₂. 22. A compound according to Claim 20 wherein i is 2.

23. A compound according to Claim 20 wherein i is 3. 24. A compound according to Claim 19 wherein R³

0 is -NHC-A. 25. A compound according to Claim 24 wherein i is 2.