Carbon beads with multimodal pore size distribution

Abstract

A method of producing a multi-modal pore distribution activated carbon is provided herein by preparing a solution comprising a polymer precursor, mixing an additional material with the polymer precursor in the solution, cross-linking the polymer precursor with the additional material mixed therein, carbonizing the mixture of the polymer precursor and the additional material, and activating the carbonized mixture to form a multi-modal pore distribution activated carbon. The multi-modal pore distribution activated carbon can include pores less than 20 Å and greater than 30 Å or 500 Å depending upon the sorption properties desired, wherein the pore distribution of the activated carbon can be tailored to provide predetermined kinetics and/or gaseous constituent equilibrium isotherms.

1 . A multi-modal pore distribution activated carbon comprising: 
 activated carbon with a first set of pores with a single mode pore distribution formed by a first carbonizable precursor and a second set of pores with a single mode pore distribution formed by a second carbonizable precursor, carbonized structures, zeolites, or combinations thereof,    wherein the first carbonizable precursor and the second carbonizable precursor, carbonized structures, zeolites, or combinations thereof, are mixed and heat treated to form the multi-modal pore distribution activated carbon, and    wherein the first set of pores has a smaller pore size than the second set of pores.    
     
     
         2 . The activated carbon of  claim 1 , wherein the activated carbon has a bimodal pore distribution of micropores and macropores.  
     
     
         3 . The activated carbon of  claim 1 , wherein the first set of pores are macropores with widths greater than about 500 Å.  
     
     
         4 . The activated carbon of  claim 1 , wherein the second set of pores are micropores with widths less than about 20 Å.  
     
     
         5 . The activated carbon of  claim 1 , wherein the second set of pores are mesopores with widths between about 20 Å and 500 Å.  
     
     
         6 . The activated carbon of  claim 1 , wherein the first carbonizable precursor comprises polysaccharide.  
     
     
         7 . The activated carbon of  claim 1 , wherein the second set of pores are formed from a second carbonizable precursor, and wherein the second carbonizable precursor comprises phenolic resin, pitch, or a combination thereof.  
     
     
         8 . The activated carbon of  claim 1 , wherein (a) the second set of pores is formed of carbonized structures, zeolites, or combinations thereof or (b) the second set of pores is formed of carbonized structures which are carbon nanotubes.  
     
     
         9 . The activated carbon of  claim 1 , wherein (a) the activated carbon has a transverse dimension of about 0.2 mm to about 6.0 mm; (b) the activated carbon is formed from a bead with a variable composition from the surface of the bead to the middle of the bead; (c) the bead forms smaller pores in the middle of the bead upon activation than on the surface of the bead upon activation; or (d) the first set of pores is formed towards the core region of the activated carbon and the second set of pores is formed towards the surface of the activated carbon.  
     
     
         10 . A method of producing a multi-modal pore distribution activated carbon comprising the steps of: 
 (i) preparing a solution comprising a polymer precursor;    (ii) mixing an additional material with the polymer precursor in the solution;    (iii) cross-linking the polymer precursor with the additional material mixed therein;    (iv) carbonizing the mixture of the polymer precursor and the additional material; and    (v) activating the carbonized mixture to form a multi-modal pore size distribution activated carbon.    
     
     
         11 . The method of  claim 10 , wherein the polymer precursor comprises a carbonizable natural polymer.  
     
     
         12 . The method of  claim 11 , wherein the carbonizable natural polymer comprises pectin or alginate.  
     
     
         13 . The method of  claim 10 , wherein (a) the additional material comprises polymers, zeolites or carbonized structures; (b) the additional material comprises phenolic resin, pitch, or a combination thereof; or (c) the additional material comprises carbonized carbon nanotubes.  
     
     
         14 . The method of  claim 10 , wherein the cross-linking comprises reacting the polymer precursor with a multivalent cation.  
     
     
         15 . The method of  claim 14 , wherein (a) the multivalent cation comprises calcium, strontium, barium, iron, silver, aluminum, magnesium, manganese, copper, zinc, or combinations thereof; or (b) the multivalent cation comprises calcium in a solution of calcium chloride, calcium acetate, or a calcium salt.  
     
     
         16 . The method of  claim 10 , wherein the carbonizing the mixture of the polymer precursor and the additional material comprises heating the mixture in a non-oxidizing environment.  
     
     
         17 . The method of  claim 10 , wherein the activating the carbonized mixture to form a multi-modal pore distribution activated carbon comprises heat treating the carbonized mixture with an oxidizing agent, wherein activation is conducted at a temperature of from about 800° C. to about 1000° C., and for a period of about 30 minutes to about 5 hours.  
     
     
         18 . A method of making different shape absorbents, comprising: 
 immobilizing and stabilizing precursors in a polysaccharide media.    Dependent from this claim further comprising activating the immobilized and stabilized precursors in the polysaccharide media.    
     
     
         19 . The method of  claim 18 , wherein the stabilization occurs below the melting temperature of the precursor.  
     
     
         20 . The method of  claim 18 , wherein the precursor comprises carbon.