초록 ▼

A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly(carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making me

A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly(carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

대표청구항 ▼

1. A method of removing a metal or metalloid ion from a dilute aqueous solution in which said ion is present, said method comprising the steps of:a) contacting said solution with a bead for a period of time sufficient to allow said bead to sorb said ion, said bead being up to about 1 mm in size and

1. A method of removing a metal or metalloid ion from a dilute aqueous solution in which said ion is present, said method comprising the steps of:a) contacting said solution with a bead for a period of time sufficient to allow said bead to sorb said ion, said bead being up to about 1 mm in size and comprising 65-94 weight percent activated carbon and 4-25 weight percent binder, said binder being selected from the group consisting of poly(carboxylic acids) and polyamines, said binder being effectively crosslinked and said activated carbon being effectively immobilized in said bead; and b) sorbing said ion onto said bead. 2. A method according to claim 1, further comprising the step of removing said sorbed ion from said bead and regenerating said bead so that said bead is reusable.3. A method according to claim 1, said dilute aqueous solution initially having less than 10 ppm of said metal or metalloid.4. A method according to claim 1, said metal or metalloid being selected from the group consisting of lead, silver, copper, iron, chromium, cobalt, uranium, mercury, nickel, arsenic, aluminum, cadmium, manganese, and zinc.5. A method according to claim 1, said bead further comprising a crosslinking agent effective to cross-link said binder, said binder being a poly(carboxylic acid), and said crosslinking agent being a polyalcohol or a mixture of polyalcohols.6. A method according to claim 5, said poly(carboxylic acid) being selected from the group consisting of poly(acrylic acid), poly(methacrylic acid), and mixtures thereof.7. A method according to claim 6, said poly(carboxylic acid) being poly(acrylic acid).8. A method according to claim 7, said poly(acrylic acid) having a molecular weight between 200,000 and 300,000.9. A method according to claim 1, said activated carbon having a particle size smaller than 100 mesh.10. A method according to claim 1, said bead further comprising a cross-linking agent effective to cross-link said binder, said binder being a polyamine, and said crosslinking agent being a dicarboxylic acid.11. A method according to claim 10, wherein said polyamine is polyethyleneimine and said crosslinking agent is glutaric acid.12. A method according to claim 1, said binder being a polyamine having a molecular weight of 60,000-100,000.13. A method according to claim 1, said bead being substantially spheroidal, globular or orbular in shape, and having a diameter of 0.3-1 mm.14. A method according to claim 1, wherein said activated carbon is granular carbon with a particle size of 40-80 mesh.15. A method according to claim 1, said activated carbon having a particle size smaller than 325 mesh.16. A method according to claim 5, said crosslinking agent being selected from the group consisting of glycerol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, and mixtures thereof.17. A method according to claim 1, said activated carbon being bituminous coal-based activated carbon.18. A method according to claim 1, said bead being in the range of 100 microns to 1 mm in size.19. A method according to claim 1, said bead being substantially spheroidal, globular or orbular in shape.20. A method according to claim 1, further comprising the step of making said bead into a substantially spheroidal, globular or orbular shape.21. A method according to claim 1, said bead being of substantially spheroidal shape.22. A method according to claim 1, said bead having a moisture content of about 1 percent by weight.23. A method according to claim 1, wherein said binder a) is sufficiently cross-linked such that said bead is dimensionally stable and not brittle, and b) retains a substantial proportion of uncross-linked functional groups which are thereby available for metal ion sorption.24. A method according to claim 23, said binder being a poly(carboxylic acid) that is cross-linked via ester linkages and that retains a substantial proportion of uncross-linked carboxylic acid functional groups.25. A method according to claim 23, said binder being a polyamine that is cross-linked via amide linkages and that retains a substantial proportion of uncross-linked amine functional groups.26. A method according to claim 1, said activated carbon having a particle size of 20-50 mesh.27. A method according to claim 1, said activated carbon being coconut based activated carbon.28. A method according to claim 1, said activated carbon being wood based activated carbon.29. A method of removing a metal or metalloid ion from a dilute aqueous solution in which said ion is present, said method comprising the steps of:a) contacting said solution with a bead for a period of time sufficient to allow said bead to sorb said ion, said bead comprising 65-94 weight percent activated carbon and 4-25 weight percent binder, said binder consisting of a poly(carboxylic acid), a polyamine, or a mixture of poly(carboxylic acids) or polyamines, said binder being effectively crosslinked and said activated carbon being effectively immobilized in said bead; and b) sorbing said ion onto said bead. 30. A method according to claim 29, said bead further comprising a cross-linking agent effective to cross-link said binder.31. A method according to claim 29, said binder consisting of a mixture of poly(carboxylic acids).32. A method according to claim 29, said binder consisting of a polycarboxylic acid that is cross linked with a minor amount of polyamine cross-linking agent.33. A method according to claim 29, said binder consisting of a polyamine that is cross-linked with a minor amount of a dicarboxylic acid.