Separation of base metals

Abstract

Use of an isolated material comprising picolinic acid ester or picolinic acid amide functional groups immobilized on a solid support for the selective removal of Ni from aqueous solutions.

Description

Technical Field

[0001] This invention relates to separation materials suitable for separating base metals, particularly separation materials for separating base metals present in lithium-ion batteries, methods for using separation materials, and methods for manufacturing such materials. Background Technology

[0002] With the increasing use of lithium-ion batteries in applications such as consumer electronics and electric vehicles, the demand for resources of the metals used in these batteries is rising. Affected metals include Ni, Co, Mn, and Li. Therefore, there is a growing need for methods to recycle components containing these metals, including lithium-ion battery waste and other metal-containing materials (such as base metal catalysts). Such recycling processes typically require the efficient separation of the relevant metals.

[0003] Therefore, it is still necessary to effectively separate metals such as Ni and / or Co in the presence of other metals, including Li and / or Mn. Summary of the Invention

[0004] The inventors have discovered that separation materials containing pyridinecarboxamide or pyridinecarboxylate functional groups (e.g., pyridinecarboxamide functional groups) immobilized on a solid support exhibit excellent Ni adsorption properties. Therefore, they can be used to separate Ni from other metals in aqueous solutions. Due to their excellent affinity for Ni, these separation materials can be used to remove Ni from solutions containing relatively high concentrations of Ni, and also to isolate low levels or trace amounts of unwanted Ni impurities from water and aqueous solutions.

[0005] Therefore, in a first preferred aspect, the present invention provides a separation material comprising a pyridinecarboxamide or pyridinecarboxylate functional group (e.g., a pyridinecarboxamide functional group) immobilized on a solid support for the selective removal of Ni from an aqueous solution. The present invention can provide a separation material comprising such functional groups immobilized on a solid support for the selective removal of Ni from an aqueous solution in the presence of Co. The present invention can provide a separation material comprising such functional groups immobilized on a solid support for the selective removal of Ni from an aqueous solution in the presence of Co and optionally Mn and / or Li.

[0006] In a second preferred aspect, the present invention provides a method for selectively removing Ni from an aqueous solution, the method comprising contacting the aqueous solution with a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups (e.g., pyridinecarboxamide functional groups) immobilized on a solid support.

[0007] The inventors have also discovered that the separating material of the present invention can be used for the chromatographic separation of Ni from certain other metals. Therefore, in a third preferred aspect, the present invention provides a separating material comprising a pyridinecarboxamide or pyridinecarboxylate functional group (e.g., a pyridinecarboxamide functional group) immobilized on a solid support for the metallographic separation of Ni from one or more other metals in aqueous solution. Typically, the one or more other metals include Co, Mn, and / or Li.

[0008] The present invention also provides a method for chromatographically separating Ni from one or more other metals in an aqueous solution, the method comprising passing an inlet aqueous solution containing Ni and one or more other metals through a stationary phase containing a separating material comprising pyridinecarboxamide or pyridinecarboxylate functional groups (e.g., pyridinecarboxamide functional groups) immobilized on a solid support; and sequentially eluting Ni and one or more other metals to provide an elution fraction containing Ni and one or more other elution fractions each containing one or more other metals.

[0009] The inventors have also discovered that the separation material of the present invention is also suitable for the chromatographic separation of Co with Li and / or Mn. Therefore, in another preferred aspect, the present invention provides a separation material comprising a pyridinecarboxamide or pyridinecarboxylate functional group (e.g., a pyridinecarboxamide functional group) immobilized on a solid support for the chromatographic separation of Co with Li and / or Mn in aqueous solution.

[0010] The present invention also provides a method for chromatographic separation of Co and Li and / or Mn in an aqueous solution, the method comprising passing an inlet aqueous solution containing Co and Li and / or Mn through a stationary phase containing a separating material comprising pyridinecarboxamide or pyridinecarboxylate functional groups immobilized on a solid support; and sequentially eluting Co and Li and / or Mn to provide an elution fraction containing Co and one or more other elution fractions each containing Li and / or Mn.

[0011] The present invention also provides a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, immobilized on a solid support, wherein the nickel loading of the separation material is at least 10 mg g. -1 .

[0012] The present invention also provides a separation material comprising pyridine carboxamide or pyridine carboxylate functional groups, such as pyridine carboxamide functional groups, immobilized on a silica support.

[0013] The present invention also provides a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, fixed on a solid support, wherein the solid support is selected from: silica solid supports, silica-polymer composite solid supports and / or optionally cross-linked methacrylate solid supports.

[0014] The present invention also provides a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, fixed on a solid support, wherein the solid support is not polystyrene.

[0015] The present invention also provides a method for preparing a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, immobilized on a solid support. For example, the method may include providing an amine functional group (preferably a primary amine) on a solid support and reacting it with pyridinecarboxylic acid. Attached Figure Description

[0016] Figure 1 , Figure 2 and Figure 3 The breakthrough curves of resins A, B, and C at pH 1 are shown (Performance Example 1).

[0017] Figure 4 , Figure 5 and Figure 6 The breakthrough curves of resins A, B, and C at pH 2 are shown (Performance Example 2).

[0018] Figure 7 The results of chromatographic separation using resin A are shown (performance example 4).

[0019] Figure 8 This demonstrates that the performance of resin A was maintained after repeated loading / elution cycles (Performance Example 5). Detailed Implementation

[0020] Preferred and / or optional features of the invention will now be set forth. Unless the context otherwise requires, any aspect of the invention may be combined with any other aspect of the invention. Unless the context otherwise requires, any preferred and / or optional feature of any aspect may be combined with any aspect of the invention, alone or in combination.

[0021] Separation materials

[0022] The separation material of the present invention comprises pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, immobilized on a solid support. The functional groups can be attached to the solid support via covalent linkers. For example, the pyridinecarboxamide functional group and its attachment to the solid support can be illustrated by Formula 1:

[0023]

[0024] Where L is a covalent linker, and R is H or an optionally substituted, branched or straight-chain C1-C6 alkyl group.

[0025] The nature of the covalent linker (e.g., L) is not particularly limited in this invention. It can be an optionally substituted C1-C6 alkyl group, wherein one or both C atoms are optionally replaced by heteroatoms. The heteroatoms can be selected from O, N, S, or Si, and are typically O or N, and typically O. The covalent linker can be a C1-C6 alkyl group.

[0026] R is typically H or a C1-C6 straight-chain alkyl group, such as H or a C1-3 straight-chain alkyl group. R may preferably be H.

[0027] The functional group of pyridinecarboxamide can be 2-pyridinecarboxamide, 3-pyridinecarboxamide or 4-pyridinecarboxamide, preferably 2-pyridinecarboxamide, which chelates nickel at low pH.

[0028] 2-Pyridinecarboxamide and its attachment to a solid support can be illustrated by Equation 2:

[0029]

[0030] Wherein L is a covalent linker, and R is H or an optionally substituted, branched or straight-chain C1-C6 alkyl group, as previously described.

[0031] This invention provides a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, immobilized on a solid support, wherein the nickel loading of the separation material is at least 10 mg g. -1 The nickel loading can be determined by contacting 20 mL of a nickel sulfate solution with a Ni concentration of 200 ppm and a pH of 2.0 with 0.062 g of the separation material and stirring at 25 °C for 18 hours. The residual Ni concentration in the solution is determined by ICP-OES and compared with a blank solution that has not been in contact with the separation material to determine the mass of Ni loaded on the separation material (Ni loading).

[0032] Solid supports are typically polymer or resin solid supports. They can be in the form of beads. A particularly suitable solid support is silica. Not wishing to be bound by theory, the inventors believe that silica supports provide a high density of attachment sites for pyridine carboxamide functional groups and a high density of binding sites for Ni, thus providing a separation material with high Ni capacity. Other suitable solid supports include optionally cross-linked methacrylate polymer solid supports and silica-polymer composite solid supports.

[0033] In some embodiments, the solid support may preferably not be polystyrene. The inventors have discovered that the tendency of polystyrene to swell during loading and elution cycles means that separation materials with polystyrene solid supports will not last as long.

[0034] Selective removal of Ni

[0035] This invention provides the use of a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups (e.g., pyridinecarboxamide functional groups) immobilized on a solid support for the selective removal of Ni from an aqueous solution, and a method for selectively removing Ni from an aqueous solution using the separation material. This invention also provides a method for the chromatographic separation of Ni from an aqueous solution with one or more other metals.

[0036] The pH of the aqueous solution can be less than 3, less than 2.5, or less than 2.1. Its pH can be at least 0.5, 0.7, 0.8, or 0.9. For example, the pH can be from 0.5 to 2.5. A pH of about 1 may be particularly convenient because this is the typical pH for base metal feedstocks in battery recycling processes. Separating materials perform particularly well at this pH compared to other separating materials. For example, the pH can be less than 1.9, 1.7, 1.5, 1.3, or 1.1. Typically, it can be from 0.5 to 1.5, such as from 0.9 to 1.1.

[0037] The aqueous solution can be recycled feedstock, for example, it can be formed by acid leaching of nickel-containing solid materials. The nickel-containing solid materials can be battery waste. Battery waste may have been previously used in energy storage devices, although this is not required. Battery waste can be waste generated during the battery or material manufacturing process, including, for example, waste intermediate materials or substandard batches. In some embodiments, battery waste is formed by mechanical and / or chemical treatment of waste lithium-ion batteries.

[0038] The aqueous solution includes nickel ions, typically Ni(II) ions. It also typically includes one or more other metal ions, such as one or more metal ions selected from Co, Li, Mn, Fe, Al, and Cu. The aqueous solution typically contains Ni and Co, such as Ni, Co, and Li, or Ni, Co, and Mn. In some embodiments, in addition to those listed, the aqueous solution contains only trace amounts of additional metals. These trace amounts of additional metals may be less than 10 mg / L, less than 5 mg / L, less than 1 mg / L, or less than 0.1 mg / L.

[0039] As understood by those skilled in the art, Ni is typically removed from aqueous solutions by adsorption (e.g., adsorption) onto a separating material. Not wishing to be bound by theory, the inventors believe that Ni adsorption is due to chemical interactions between Ni ions and pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, present on the surface and optionally in the pores of a solid support.

[0040] In this invention, Ni can be separated from other metals by loading a separation material with Ni ions (wherein Ni ions are adsorbed onto the separation material), followed by contacting the separation material with an eluent to desorb the Ni ions. This loading and elution cycle can be repeated 2 or more, 3 or more, 4 or more, 5 or more, 8 or more, or 10 or more times. This is particularly advantageous because it allows for the recovery of the separation material and enables its use for a period of time. Typically, the eluent is an aqueous solution with a pH less than 0.5, less than 0.3, or less than 0.1. It can have a pH greater than -1. The eluent is typically acidic. A suitable eluent is 2M H₂SO₄. Other suitable eluents include HCl.

[0041] Chromatographic separation

[0042] The inventors have discovered that the separating material of this invention can be used to chromatographically separate Ni from certain other metals in aqueous solutions. Typically, aqueous solutions are as defined above regarding the selective removal of Ni.

[0043] A method for chromatographically separating Ni from one or more other metals in an aqueous solution includes passing an inlet aqueous solution containing Ni and one or more other metals through a stationary phase containing the separation material of the present invention, and sequentially eluting Ni and one or more other metals to provide an elution fraction containing Ni and one or more other elution fractions each containing one or more other metals.

[0044] Typically, Mn and / or Li can be selectively eluted using water or an aqueous solution with a pH greater than 3, 4, 5, 6, or 6.5. The pH can be less than 8 or less than 7.5.

[0045] Typically, Co can be selectively eluted using aqueous solutions with a pH greater than 0.5, 0.7, 0.8, or 0.9. Its pH can be less than 3, 2, or 1.5. The pH of the Co eluent can be decreased sequentially within this range to ensure substantially complete elution. For example, an aqueous solution of H₂SO₄ can be used.

[0046] Ni can typically be eluted using an aqueous solution with a pH less than 0.5, 0.3, or 0.1. Its pH can be greater than -1. The eluent is usually acidic. A suitable eluent is 2M H₂SO₄. Other suitable eluents include HCl.

[0047] Typically, the metals are eluted in the order of Mn and / or Li, then Co, and then Ni. A water wash can be performed after Ni elution.

[0048] The inventors have also discovered that the separating material of the present invention is also suitable for the chromatographic separation of Co from Li and / or Mn in aqueous solutions. The aqueous solution includes Co ions, typically Co(II) ions. It typically also includes one or more other metal ions, such as one or more metal ions selected from Li, Mn, Fe, Al, and Cu, such as one or more metal ions selected from Li, Mn, and Fe, such as one or more metal ions selected from Li and Mn. The aqueous solution typically contains Co and Li and / or Mn, typically Co, Li, and Mn. In some embodiments, in addition to those listed, the aqueous solution contains only trace amounts of additional metals. The trace amounts of additional metals may be less than 10 mg / L, less than 5 mg / L, less than 1 mg / L, or less than 0.1 mg / L.

[0049] Co and Mn and / or Li can be selectively eluted using chromatographic methods with Ni present, as described above.

[0050] Methods for manufacturing separation materials

[0051] The present invention also provides a method for preparing a separation material comprising pyridinecarboxamide or pyridinecarboxylate functional groups, such as pyridinecarboxamide functional groups, immobilized on a solid support. For example, the method may include reacting an amine functional group (preferably a primary amine) provided on the solid support with pyridinecarboxylic acid. The solid support may be as defined above. The reaction with pyridinecarboxylic acid may be carried out in the presence of 1,1'-carbonyldiimidazole. The reaction with pyridinecarboxylic acid may be carried out for at least 5, 10, or 15 hours, for example under reflux conditions.

[0052] Example

[0053] Preparation Example 1 - Preparation of 3-aminopropyl-functionalized silica ("silica-AP")

[0054] Silica (20.0 g dry weight) was placed in a 250 mL three-necked round-bottom flask reactor. A mixture of (3-aminopropyl)trimethoxysilane (3.6 g, 3.6 mL) and toluene (60 mL) was prepared and slowly added to the reactor. The reactor was then placed on a heating plate and fitted with a paddle stirrer powered by an overhead motor with an airtight stirrer cap. The mixture was stirred at 50 rpm and reacted overnight at an external temperature of 100 °C. The reaction mixture was allowed to cool, filtered, washed with 3 × 20 mL toluene, and dried in a vacuum oven at 40 °C.

[0055] Preparation Example 2 - Preparation of pyridine carboxamide-functionalized silica

[0056] 0.75 g of pyridinecarboxylic acid was placed in a 250 mL three-necked round-bottom flask reactor. Then, 60 mL of dichloromethane (DCM) was added to the reactor, which was then placed on a heated plate equipped with a paddle stirrer powered by an overhead motor with an airtight stirrer cap and a calcium chloride shield. The mixture was stirred until the pyridinecarboxylic acid was completely dissolved. Then, 0.97 g of 1,1'-carbonyldiimidazole (CDI) was slowly added to the reactor (bubbling to release CO2 byproducts) and mixed for 30 minutes. 5.0 g of silica-AP (dry weight, as prepared in Example 1) was added to the reactor. The mixture was stirred at 50 rpm and refluxed overnight (external temperature 50°C). The reactor was allowed to cool, the solids were filtered, washed with DCM, methanol, and deionized water (3 × 20 mL per step), and dried in a vacuum oven at 40°C.

[0057] The reaction scheme for this reaction is as follows:

[0058]

[0059] Preparation Example 3 - Preparation of Glycidyloxypropyl Functionalized Silica

[0060] Silica (20.0 g dry weight) was placed in a 250 mL round-bottom flask. A mixture of (3-glycidyloxypropyl)trimethoxysilane (4.1 g, 4.4 mL) and methanol (60 mL) was prepared in a separate conical flask and slowly added to the reactor. The reactor was then placed in a rotary evaporator, and the reaction was carried out for 5 hours with a stirring speed of 50 rpm and an external temperature of 90 °C. Within the first 10–15 minutes, all the methanol evaporated from the reactor and was collected in a separate container. The reaction was allowed to cool, washed once with 60 mL of methanol, and then twice with 60 mL of deionized water. The final product, silica-GOP, was filtered and dried in a vacuum oven at 40 °C.

[0061] Preparation Example 4 - Preparation of pyridine methylamine functionalized silica

[0062] The silica-GOP (10.0 g dry weight) prepared in Preparation Example 3 was placed in a 250 mL three-necked round-bottom flask and placed on a heating plate equipped with a paddle stirrer powered by a top-mounted motor with an airtight stirrer cap. Then, a mixture of 2-pyridinemethylamine (5.98 g, 5.7 mL) and methanol (30 mL) was prepared in a separate conical flask and added to the reactor. The mixture was stirred at 50 rpm and the reaction was refluxed overnight (external temperature 80 °C). The reactor was cooled, the solids were filtered and collected in a sleeve, and then washed with methanol by Soxhlet extraction for 2 hours. The final product, silica-GOP-PA, was then filtered and dried in a vacuum oven at 40 °C.

[0063] The reaction scheme for this reaction is as follows:

[0064]

[0065] Preparation Example 5 - Preparation of pyridine carboxamide-functionalized polystyrene

[0066] In a 100 mL three-necked round-bottom flask, pyridinecarboxylic acid (3.1 g) was dispersed in 30 mL of DCM and continuously stirred with a top stirrer. Then, CDI (4.1 g) was added to the reactor, producing some effervescence due to the release of CO2. Once effervescence ceased (approximately 30 minutes), amine-functionalized poly(styrene-co-divinylbenzene) was added... VP OC 1065 (5.0 g) was added to the reactor, and the reaction was heated under reflux overnight under anhydrous conditions (CaCl2 shield). The final product was a dark gray solid, which was filtered off, washed with DCM by Soxhlet extraction for 10 cycles, washed with water, and dried under vacuum at 40 °C for 6 h.

[0067] The reaction scheme for this reaction is as follows:

[0068]

[0069] Performance Example 1 - Nickel Adsorption at pH 1

[0070] Sulfates of each metal were used to prepare a solution containing 500 mg L of their respective metals. -1 The feed aqueous solution of Co(II), Fe(III), Li, Mn(II) and Ni was prepared and the pH was adjusted to pH 1.0 using sulfuric acid.

[0071] The feed solution is passed through a bed containing resins A, B, and C (see Table 1 below for resin details). The resins are equilibrated by acid rinsing followed by water rinsing. Figure 1 , Figure 2 and Figure 3 The breakthrough curves of resins A, B, and C are shown respectively.

[0072] Table 1

[0073] Resin B Silica pyridine methylamine prepared as in Preparation Example 4 Resin C M4195 was obtained from Dow Chemical (2-dipyridinemethylamine functionalized polystyrene).

[0074] The column used had an inner diameter of 10 mm, a packed length of 120 mm, and a total volume of 9.4 mL (considered as one bed volume, BV), and was operated at 6 BV / hr (0.94 mL / min, 56.4 mL / hr).

[0075] The results are as follows Figure 1 , Figure 2 and Figure 3 As shown. Figure 1Results for resin A are shown, demonstrating that Ni was completely adsorbed in the first five bed volumes before breakthrough began. In contrast, other metals in the feed began to breakthrough immediately. This indicates that resin A selectively adsorbs Ni at pH 1 in the presence of Co, Fe, Li, and Mn, and is therefore suitable for separating Ni from these metals at pH 1. Figure 2 The results for resin B are shown, and it is demonstrated that Ni penetration was observed immediately. Figure 3 The results for resin C are shown, and Ni breakthrough was also observed immediately. Therefore, resins B and C are not suitable for the selective adsorption of Ni at pH 1 in the presence of Co, Fe, Li, and Mn.

[0076] This indicates that the pyridine carboxamide functional group is superior to the pyridine methylamine and 2-dipyridine methylamine functional groups for selective adsorption of Ni.

[0077] The three resins tested were recovered using three different bed volumes (28.2 mL) of the selected eluent. 100% of the adsorbed nickel was successfully removed from resins A and B using 2 M H₂SO₄. Ni removal from resin C required elution with ammonia. MSDS indicated that the material swells / degrades upon contact with ammonia.

[0078] Performance Example 2 - Nickel Adsorption at pH 2

[0079] Except for using sulfuric acid to adjust the feed solution to pH 2.0, the scheme of Example 1 can be replicated.

[0080] Figure 4 The results for resin A are shown, again demonstrating that Ni was completely adsorbed in the first five bed volumes. Figure 5 The results for resin B are shown. Compared to the performance of resin B at pH 1.0, Ni adsorption is greater, but Ni penetration can still be seen immediately. Figure 6 The results for resin C are shown. Greater Ni adsorption was observed compared to the performance of resin C at pH 1.0.

[0081] Performance Example 3 - Nickel Loading

[0082] According to the following scheme, the nickel loading of resin A and resin D (such as the pyridine carboxamide-functionalized polystyrene prepared in Preparation Example 5) was tested using a single-point capacity test.

[0083] The metal adsorption capacity of the resin was determined at pH 2.0 using 20 mL of a nickel sulfate solution with a nickel concentration of 200 ppm. The metal solution was prepared by dissolving an appropriate mass of sulfate in deionized water and adjusting the pH with sulfuric acid. Different materials were weighed into multiple parallel tubes, each with a mass of 0.062 g. The resin and solution were contacted and stirred for 18 hours. All samples, including untreated blank samples, were analyzed by ICP-OES. The metal concentration of the blank (untreated) samples was compared with that of the treated samples, and the metal capacity was described as the mass of metal adsorbed by the resin (mg / g). -1 ).

[0084] The results are shown in Table 2 below:

[0085] Table 2

[0086] Resin A <![CDATA[15mg g -1 ]]> Resin D <![CDATA[3mg g -1 ]]>

[0087] These results indicate that pyridine carboxamide-functionalized silica has a higher nickel capacity than pyridine carboxamide-functionalized polystyrene, although both exhibit significant nickel absorption. It is believed that polystyrene-based resins are unsuitable for repeated loading / elution cycles due to their tendency to swell.

[0088] Performance Example 4 - Chromatographic Separation

[0089] A solution containing Co(II), Li, Mn(II), and Ni (each metal sulfate concentration 500 mg / L) at pH 2 was prepared. -1 The solution was subjected to chromatographic separation. The solution was the mobile phase, and resin A was the stationary phase. The bed volume (BV) was 9.4 mL.

[0090] The initial injection was 1 BV via a stationary phase pump. It was observed that Li and Mn were not adsorbed by the resin, while Ni and Co were loaded onto it. Gradient elution with H₂O was then performed to remove the unadsorbed remaining Li and Mn. This was followed by 3 BV of H₂SO₄ solutions at different pH values, and finally a water wash. The complete elution process is shown in Table 3 below.

[0091] Table 3

[0092] <![CDATA[H₂SO₄ solution with pH 1.3]]> 3BV <![CDATA[H₂SO₄ solution with pH 1.0]]> 3BV <![CDATA[2M H2SO4]]> 3BV <![CDATA[H2O]]> 3BV

[0093] The results are as follows Figure 7 As shown, this demonstrates that chromatographic separation using pyridine-formamide-functionalized resins can successfully separate Ni and Co from each other (as well as from Li and Mn). Most Co can be eluted with pH 1.3 H₂SO₄, but a low pH (1.0) is required for complete elution. Under these conditions, Ni remains on the medium and is eluted with 2M H₂SO₄. Thus, complete separation of Ni and Co is achieved.

[0094] Performance Example 5 - Stability of Resin A

[0095] The repeatability of resin A is the same as in Example 1, but the feed solution is adjusted to pH 2.0 using sulfuric acid, and the loading cycle is repeated twice after eluting nickel with 2M sulfuric acid. Figure 8 The results show that the Ni capacity was retained after repeated loading / elution cycles, demonstrating the stability of resin A.

[0096] Examples of pyridine carbamates

[0097] Previous examples used the pyridinecarboxamide (pyridinecarboxamide) functional group. However, other examples according to the invention may also utilize the corresponding pyridinecarboxylate group. In this respect, it has been found that pyridinecarboxylates can also chelate nickel. For example, an acidic solution of ethyl 2-pyridinecarboxylate (0.04 M) and nickel (0.01 M) was prepared, and the chelation was confirmed by the color of the solution changing from green to blue, the same color as the nickel-pyridinecarboxamide complex.

[0098] While the invention has been specifically shown and described with reference to certain examples, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. The use of a separation material containing 2-pyridinecarboxamide functional groups immobilized on a solid support for the selective removal of Ni from an aqueous solution.

2. The use according to claim 1, wherein the use comprises selectively removing Ni from an aqueous solution in the presence of Co and optionally Mn and / or Li.

3. The use according to claim 1, wherein the 2-pyridinecarboxamide functional group and its attachment to the solid support are shown by formula 2: Formula 2 Where L is a covalent linker, and R is H or an optionally substituted, branched or straight-chain C1-C6 alkyl group.

4. The use according to claim 1, wherein the solid carrier is selected from: silica solid carrier, silica-polymer composite solid carrier and / or optionally cross-linked methacrylate solid carrier.

5. The use according to claim 4, wherein the solid support is a silica solid support.

6. The use according to claim 1, wherein the pH of the aqueous solution is from 0.5 to 2.

5.

7. The use according to claim 6, wherein the pH of the aqueous solution is from 0.5 to 1.

5.

8. The use according to any one of the preceding claims, wherein the aqueous solution is a recycled feed, optionally derived from battery waste.

9. A method for selectively removing Ni from an aqueous solution, the method comprising contacting the aqueous solution with a separating material comprising 2-pyridinecarboxamide functional groups immobilized on a solid support.

10. A method for chromatographically separating Ni from one or more other metals in an aqueous solution, the method comprising: An inlet aqueous solution containing Ni and one or more other metals is passed through a stationary phase containing a separation material, said separation material containing 2-pyridinecarboxamide functional groups immobilized on a solid support; And sequentially elute Ni and one or more other metals to provide an elution fraction containing Ni and one or more other elution fractions each containing one or more other metals.

11. A method for chromatographic separation of Co from Li and / or Mn in an aqueous solution, the method comprising: An inlet aqueous solution containing Co and Li and / or Mn is passed through a stationary phase containing a separation material comprising 2-pyridinecarboxamide functional groups immobilized on a solid support; and Co and Li and / or Mn are eluted sequentially to provide an elution fraction containing Co and one or more other elution fractions each containing Li and / or Mn.

12. A separation material comprising a 2-pyridinecarboxamide functional group immobilized on a solid support, wherein the nickel loading of the separation material is at least 10 mg g. -1 .

13. A separation material comprising a 2-pyridinecarboxamide functional group immobilized on a solid support, wherein the solid support is selected from: a silica solid support, a silica-polymer composite solid support, and / or optionally a cross-linked methacrylate solid support.

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