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CN-121986074-A - Removal of metal species

CN121986074ACN 121986074 ACN121986074 ACN 121986074ACN-121986074-A

Abstract

The present disclosure relates to methods for removing a metal species, such as a metal cation, from a solution comprising the metal species and a solvent. The method includes treating a solution with a polymer comprising an ionizable group and a ligand to form a complex, and treating the solution with a precipitant.

Inventors

  • K. Handes
  • S. Collie
  • N. Hankins

Assignees

  • 塞洛西姆有限公司

Dates

Publication Date
20260505
Application Date
20240822
Priority Date
20230825

Claims (20)

  1. 1. A method for removing a metal species from a solution, wherein the solution comprises the metal species and a solvent, the method comprising treating the solution with a polymer comprising an ionizable group and a ligand to form a complex; Wherein the ionizable groups of the polymer are basic and the ligand comprises at least one acidic group, or wherein the ionizable groups of the polymer are acidic and the ligand comprises at least one basic group; Wherein the ligand comprises at least one group that binds the metal species; And wherein the precipitant comprises at least one group that binds the metal species and/or the polymer, and at least one hydrophobic moiety.
  2. 2. The method of claim 1, wherein the ligand electrostatically binds the polymer.
  3. 3. The method of claim 1 or claim 2, wherein the complex comprises: a positively charged species formed by the polymer and a negatively charged species formed by the ligand, or a negatively charged species formed by the polymer and a positively charged species formed by the ligand, and -A metal species.
  4. 4. The method according to any of the preceding claims, wherein the method comprises: Mixing the polymer with the ligand to form a salt, wherein the salt comprises a positively charged species formed from the polymer and a negatively charged species formed from the ligand, or a negatively charged species formed from the polymer and a positively charged species formed from the ligand; Or wherein the method comprises: (i) Mixing the polymer with the ligand to form a salt, wherein the salt comprises a positively charged species formed from the polymer and a negatively charged species formed from the ligand, or a negatively charged species formed from the polymer and a positively charged species formed from the ligand, and (Ii) Treating a solution comprising a metal species and a solvent with the salt formed in step (i) to form a complex as defined in claim 1, and treating the solution with the precipitant.
  5. 5. The method of claim 4, wherein the salt is in a liquid phase.
  6. 6. The method of claim 5, wherein the liquid phase salt is an aqueous salt solution.
  7. 7. The method of any one of the preceding claims, wherein treatment with the precipitating agent results in precipitation of the complex from solution.
  8. 8. The method of any one of the preceding claims, wherein the metal species is selected from noble metal species.
  9. 9. The method of claim 8, wherein the metal species is selected from a platinum group metal species, a copper species, a gold species, a silver species, or a combination thereof.
  10. 10. The method of any one of the preceding claims, wherein the metal species is a metal ion.
  11. 11. The method of claim 10, wherein the metal species is a metal cation.
  12. 12. The method of any one of the preceding claims, wherein the ionizable groups of the polymer are basic and the ligand comprises at least one acidic group.
  13. 13. The method of claim 12, wherein the ionizable groups of the polymer are N-containing groups.
  14. 14. The method of claim 12 or claim 13, wherein the polymer comprises polyethylenimine, polyvinylamine, polyallylamine, chitosan, polylysine, polyarginine, or a combination thereof.
  15. 15. The method of any one of claims 12 to 14, wherein the at least one acidic group of the ligand is selected from a carbon-based acid, a sulfur-based acid, a phosphorus-based acid, or a combination thereof.
  16. 16. The method of claim 15, wherein the at least one acidic group of the ligand is selected from the group consisting of a carboxyl group, a sulfonic acid group, a phosphoric acid group, a phosphinic acid group, and a phosphonic acid group.
  17. 17. The method of claim 16, wherein at least one acidic group is a carboxyl group, or a sulfonic acid group, or a phosphonic acid group.
  18. 18. The method of any one of claims 1 to 11, wherein the ionizable groups of the polymer are acidic and the ligand comprises at least one basic group.
  19. 19. The method of claim 18, wherein the ionizable groups of the polymer are selected from carboxyl groups, sulfonic acid groups, phosphate groups, phosphinate groups, phosphonate groups, or combinations thereof.
  20. 20. The method of claim 19, wherein the ionizable groups of the polymer are selected from carboxyl groups and sulfonic acid groups.

Description

Removal of metal species Technical Field The present disclosure relates to methods for removing metal species, such as metal cations, from a solution comprising the metal species and a solvent. Background There are many known methods for removing charged species from liquid phase effluents, including methods for removing charged metal species. Examples of effluents that typically contain charged species that need to be removed, or that they will be both economically, environmentally and (in turn) socially beneficial are effluents from the metal finishing (METAL FINISHING) industry, the mining and mineral processing industry, the textile and battery industry, the catalyst manufacturing industry and soil washing of lands contaminated with heavy metals and pharmaceutical processes in which metal catalysts are used. Metal ions are widely used in industrial processes and such use means that they are present in the associated effluent stream. As mentioned above, there is an economic and environmental incentive for removing metal ions from liquid phase effluents. Environmental incentives stem from increasingly stringent emissions regulations. The metal ions are not biodegradable and can bioaccumulate in the body of humans and other animals, resulting in potentially harmful effects on health. Economic incentives stem from the market value of specific metal species, platinum Group Metals (PGMs), and gold may, for example, have a market value of about less than 30/g to less than 50/g. Thus, recovery of such metals from the effluent is worthwhile, provided that a cost effective and efficient process is available. The removal and recovery of such metal species, particularly platinum group species, gold and silver, is further beneficial from a sustainability standpoint. Industrial processes can be carried out on a large scale and thus produce significant levels of waste. When such waste comprises precious metals, for example from the use of catalysts in industrial processes, the precious metal species to be recovered in large quantities and ideally recycled are economically and environmentally desirable. Industrial processes a wide variety of noble metal-containing catalysts are used in the manufacture of pharmaceuticals and other products. For example, palladium is widely used to facilitate cross-coupling, rhodium is used for hydroformylation reactions, and platinum is used for asymmetric hydrogenation. Known metal ion removal techniques have their advantages and limitations in a variety of applications. The method generally used is ion exchange. Ion exchange is effective for removing small amounts of water contaminated with high concentrations of metal ions, but the cost and secondary pollution are critical when regenerating resins. Furthermore, the required solid-liquid, fixed bed operation is complex and solid-liquid fixed bed operation is not efficient in a single pass due to inherent mass transfer limitations between the phases. Therefore, ion exchange resins are uneconomical for rapid treatment of large amounts of metal ion wastewater. Electrochemical technology is considered a fast and well controlled method to remove metals with less chemical addition and less sludge (slip) generation. Disadvantages are high capital and operating costs, limited selectivity and complexity of operation. Adsorption is an alternative method, but this method suffers from similar drawbacks to ion exchange, and the balance between cost and effectiveness of physicochemical adsorbents is difficult. Bioadsorption has proven to be a promising sustainable removal method. The advantage is a high overflow rate (rate) and a low concentrated sludge volume. However, this capital, maintenance and operating cost is high. Sludge produced by the biosorption coagulation-flocculation process has good settling and dewatering properties, but the amount of chemicals used (dosage), lack of selectivity, and sludge treatment/disposal are major drawbacks to overcome. Finally, membrane filtration technology is a selective removal method based on species size, but high cost, membrane fouling and low permeate flux are limitations. Methods for removing metal ions are disclosed, for example, in Hankins et al ,Separation and Purification Technology, 2006, 51(1), 48-56; WO 2016/079511; Shen et al., Separation and Purification Technology, 2015, 152, 101-107; Shen et al., Separation and Purification Technology, 2016, 159, 169-176; Shen et al., Emerging Membrane Technology for Sustainable Water Treatment, 2016, 249; Shen et al., Desalination, 2017, 406, 109-118; and Shen et al, desalination, 2017, 406, 67-73. Such methods use polymers to remove charged species from solution, including using polymer-surfactant aggregates to avoid sludge generation and provide an environmentally friendly method to remove charged species. However, there is room for improvement in the above-described methods, particularly in the field of selectively removing specific ions from mixtures o