Adsorbents, systems and methods for the removal of heavy metals from contaminated water
An adsorbent for a target compound can include porous carbon particles having pores with a predominant pore size less than 10 nm, and magnetic nanoparticles (MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA). A method for removing target compounds with an adsorbent, a system for removing contaminants from a liquid, and a method for adsorbing target compounds from a fluid are also disclosed.
1. An adsorbent for a target compound, comprising porous carbon particles having pores with a predominant pore size less than 10 nm, and magnetic nanoparticles (MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA).
2. The adsorbent of claim 1 , wherein the pores of the porous carbon comprise a mixture of micropores having a pore size less than 2 nm, mesopores having a pore size of from 2-50 nm, and macropores having pore size greater than 50 nm.
3. The adsorbent of claim 1 , wherein the carbon comprises tire derived carbon (TDC).
4. The adsorbent of claim 1 , wherein the carbon comprises activated carbon.
5. The adsorbent of claim 1 , wherein the carbon particle size is 10-2000 microns.
6. The adsorbent of claim 1 , wherein the MNP particle size is 2-100 nm with predominant size of less than 10 nm.
7. The adsorbent of claim 1 , wherein the surface area of the carbon is from 200-1200 m 2 /g.
8. The adsorbent of claim 7 , wherein after impregnation with the MNP, the surface area of the carbon in the C-MNA is 10-100 m 2 /g.
9. The adsorbent of claim 7 , wherein after impregnation with the MNP, the surface area of the carbon in the C-MNA is 25-50 m 2 /g.
10. The adsorbent of claim 1 , wherein the proportion of MNP to carbon is from 1-30%, by weight based on the total weight of the carbon and MNP.
11. The adsorbent of claim 1 , wherein the target compounds comprise compounds that will chemically coordinate with the MNP.
12. The adsorbent of claim 1 , wherein the MNP comprises at least one selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , FeO, CoO, CO 2 O 3 , Co 3 O 4 , CrO, Gd 2 O 3 , Dy 2 O 3 , MnBi, BaFe 12 O 19 , SrFe 12 O 19 , M 2 Fe 2 O 4 (M=Co; Zn; Mn,Zn; Co,Zn; Fe,Zn; Ni,Zn), FeNi, FeCo, FeSi, Nd 2 Fe 14 B, Sm 2 Co 5 , Sm 2 Co 17 , SmFe 16 N 2 , and Fe 16 N 2 .
13. The adsorbent of claim 1 , wherein the target compound comprises at least one selected from the group consisting of selenium, tellurium, chromium, copper, cadmium, barium, mercury, arsenic and lead.
14. The adsorbent of claim 1 , wherein the adsorption capacity of the adsorbent is from 7 mg/g to 100 mg/g of target compound to C-MNA.
15. A method for removing target compounds with an adsorbent, comprising the steps of:
providing a magnetically activated adsorbent for the target compounds, comprising porous carbon particles having pores with a pore size less than 10 nm, and magnetic nanoparticles (MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA);
contacting the target compounds with the C-MNA.
16. The method of claim 15 , further comprising the step of regenerating the adsorbent to remove contaminant from the adsorbent.
17. The method of claim 16 , wherein the regeneration step comprises treating the adsorbent with a basic solution.
18. The method of claim 17 , wherein the basic solution comprises 0.1-1 molar NaOH.
19. The method of claim 16 , wherein target compounds are contained within a liquid, and the regenerating step comprises the step of separating the used adsorbent particles from the liquid.
20. The method of claim 19 , further comprising the step of, after contacting the C-MNA particles with the target compound, applying a magnetic field to attract the C-MNA particles with the target compound, and separating and regenerating the C-MNA particles.
21. The method of claim 15 , wherein the target compounds are contained in a liquid, and further comprising the step of adjusting the pH before the contacting step.
22. The method of claim 21 , wherein the adjusting step comprises adjusting to a pH of from 3-10.
23. The method of claim 22 , wherein the target compounds are contaminants and are provided in a liquid waste stream, and further comprising the step of treating the waste stream to raise the pH.
24. The method of claim 15 , wherein the contacting step comprises positioning the adsorbent in a column, and flowing the target compounds through the column to contact the adsorbent.
25. The method of claim 24 , further comprising the step of adding silica to the column to increase the macroporosity of the column and prevent clogging.
26. The method of claim 25 , wherein the amount of silica that is added is from 5-50 weight percent based on the combined weight percentage of the adsorbent and the silica.
27. The method of claim 26 , further comprising the step of adding a filler, the filler comprising 10-40 weight percentage of cotton, based on the total weight of the C-MNA, silica, and cotton.
28. The method of claim 15 , wherein the target compounds comprise compounds that will chemically coordinate with the MNP.
29. The method of claim 15 , wherein the target compound comprises at least one selected from the group consisting of selenium, tellurium, chromium, copper, cadmium, barium, mercury, arsenic and lead.
30. The method of claim 29 , wherein the target compound is a cation.
31. The method of claim 30 , wherein the cation comprises at least one selected from the group consisting of the 4 + oxidation state of selenium (Se 4+ ) and the 5+ oxidation state of arsenic (As 5+ ).
32. The method of claim 15 , wherein the MNP comprises at least one selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , FeO, CoO, CO 2 O 3 , Co 3 O 4 , CrO, Gd 2 O 3 , Dy 2 O 3 , MnBi, BaFe 12 O 19 , SrFe 12 O 19 , M 2 Fe 2 O 4 (M=Co; Zn; Mn,Zn; Co,Zn; Fe,Zn; Ni,Zn), FeNi, FeCo, FeSi, Nd 2 Fe 14 B, Sm 2 Co 5 , Sm 2 Co 17 , SmFe 16 N 2 , Fe 16 N 2 , and Fe 3 O 4 .
33. A system for removing contaminants from liquids, comprising:
a container;
an adsorbent in the container, the adsorbent comprising porous carbon particles having pores with a pore size less than 10 nm, and magnetic nanoparticles (MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA).
34. The system of claim 33 , wherein the container comprises a fluid inlet and a fluid outlet, fluid flowing in through the inlet, through the adsorbent, and out through the outlet.
35. The system of claim 34 , wherein the container is a column.
36. The system of claim 35 , wherein the column comprises silica.
37. The system of claim 36 , wherein the liquid is a slurry.
38. The system of claim 33 , wherein the C-MNA is provided on a support.
39. The system of claim 38 , wherein the support comprises a filter.
40. The system of claim 33 , further comprising a magnetic field source for attracting C-MNA particles with adsorbed target compound for regeneration of the C-MNA particles.
41. A method of adsorbing target compounds from a fluid, comprising the steps of:
providing a container;
providing an adsorbent in the container, the adsorbent comprising porous carbon particles having pores with a pore size less than 10 nm, and magnetic nanoparticles(MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA);
contacting the target compounds with the adsorbent in the container.
42. The method of claim 41 , wherein the target compound comprises at least one selected from the group consisting of selenium, tellurium, chromium, copper, cadmium, barium, mercury, arsenic and lead.
43. The method of claim 41 , wherein the C-MNA particles are adhered to a filter, and the liquid is caused to flow through the filter.