Catalytic activated carbon for removal of chloramines from water

Abstract

This application discloses a method for enhanced removal of chloramines from a chloramines-containing fluid media by contacting said media with a catalytic activated carbon characterized by having present in the graphene structure of the carbon from 0.01 to 10 wt % of aromatic nitrogen species. The catalytic activated carbons used in the present invention may be prepared from carbon materials that have been contacted or otherwise exposed to ammonia, with or without simultaneous exposure to an oxygen-containing vapor or gas at temperatures above 700° C. and, preferably, are in the form of a solid carbon block.

What is claimed is:  
     
         1 . A process for the removal of chloramines from chloramine-containing fluid solutions or streams comprising the step of contacting said solutions or streams with an activated carbon characterized by having present in the graphene structure of the carbon from 0.01 to 10 wt % of aromatic nitrogen species.  
     
     
         2 . The process of  claim 1  wherein the carbon has been treated by a process of pyrolyzing the carbon while simultaneously passing a gas stream containing NH3 through a bed of the carbon.  
     
     
         3 . The process of  claim 1  wherein at least 10% of the nitrogen is positioned as an aromatic center configuration within a graphene layer.  
     
     
         4 . The process of  claim 2  wherein the gas stream includes both NH3 and an oxygen-containing gas or vapor.  
     
     
         5 . The process of  claim 4  wherein the gas stream includes a NH 3 /oxygen-containing gas mixture from the group consisting of NH 3 /CO 2 , NH 3 /O 2 , NH 3 /H 2 O, and NH 3 /NOX.  
     
     
         6 . The process of  claim 5  wherein the NH 3 /oxygen-containing gas mixture is NH 3 /H 2 O.  
     
     
         7 . The process of  claim 1  wherein the solutions or streams are aqueous.  
     
     
         8 . The process of  claim 1  wherein the activated carbon is derived from a carbon-containing material.  
     
     
         9 . The process of  claim 8  where the carbon-containing material contains nitrogen in its chemical structure.  
     
     
         10 . The process of  claim 8  wherein the activated carbon is derived from a material selected from coal, wood, nut shell, pitch, peat, fruit pit, cellulose, lignin, and agricultural waste materials.  
     
     
         11 . The process of  claim 1  wherein the pyrolyzing temperature is above about 700° C.  
     
     
         12 . The process of  claim 1  where the carbon is shaped in the form of a block.  
     
     
         13 . The process of  claim 3  where the carbon is shaped in the form of a block.  
     
     
         14 . The process of  claim 9  where the carbon is shaped in the form of a block.  
     
     
         15 . The process of  claim 1  wherein the carbon is characterized by the presence in the graphene structure of the carbon of from 0.02 to 7 wt % of aromatic nitrogen species.  
     
     
         16 . The process of  claim 15  wherein the carbon is characterized by the presence in the graphene structure of the carbon of from 0.03 to 5 wt % of aromatic nitrogen species.  
     
     
         17 . An activated carbon useful for the removal of chloramines from chloramine-containing fluid solutions or streams wherein the carbon is characterized by the presence in the graphene structure of the carbon of from 0.01 to 10 wt % of aromatic nitrogen species.  
     
     
         18 . The carbon of  claim 17  wherein the solutions or streams are aqueous.  
     
     
         19 . The carbon of  claim 17  wherein the activated carbon is derived from a carbon-containing material.  
     
     
         20 . The carbon of  claim 19  wherein the activated carbon is derived from a material selected from coal, wood, nut shell, pitch, peat, fruit pit, cellulose, lignin, and agricultural waste materials.  
     
     
         21 . The carbon of  claim 17  wherein at least 10% of the nitrogen is positioned as an aromatic center configuration within a graphene layer.  
     
     
         22 . The carbon of  claim 17  wherein the carbon has been treated by a process of pyrolyzing the carbon while simultaneously passing a gas stream containing NH3 through a bed of the carbon.  
     
     
         23 . The carbon of  claim 22  wherein the gas stream includes both NH3 and an oxygen-containing gas or vapor.  
     
     
         24 . The carbon of  claim 23  wherein the gas stream includes a NH 3 /oxygen-containing gas mixture from the group consisting of NH 3 /CO 2 , NH 3 /O 2 , NH 3 /H 2 O, and NH 3 /NO x .  
     
     
         25 . The carbon of  claim 24  wherein the NH 3 /oxygen-containing gas mixture is NH 3 /H 2 O.  
     
     
         26 . The carbon of  claim 23  wherein the pyrolyzing temperature is above about 700° C.  
     
     
         27 . The carbon of  claim 17  wherein the carbon is characterized by the presence in the graphene structure of the carbon of from 0.02 to 7 wt % of aromatic nitrogen species.  
     
     
         28 . The carbon of  claim 27  wherein the carbon is characterized by the presence in the graphene structure of the carbon of from 0.03 to 5 wt % of aromatic nitrogen species.  
     
     
         29 . The carbon of  claim 19  wherein the carbon-containing material is in the form of a single compound comprising nitrogen in its chemical structure.  
     
     
         30 . The carbon of  claim 21  wherein the carbon is shaped in the form of a block.  
     
     
         31 . The carbon of  claim 27  wherein the carbon is shaped in the form of a block.  
     
     
         32 . The carbon of  claim 28  wherein the carbon is shaped in the form of a block.