Sorption And Separation of Various Materials By Graphene Oxides

Abstract

Methods of sorption of various materials from an environment are disclosed herein. Embodiments of the materials include radioactive elements chlorates, perchlorates, organohalogens, and combinations thereof. Other embodiments pertain to methods of sorption of cationic radionuclides. Compositions produced by such methods are also disclosed herein. Embodiments of the methods may include contacting graphene oxides with the environment and sorption of the materials to the graphene oxides. In some embodiments, the sorption is relatively rapid in comparison to known sorbents; even in the presence of relatively higher concentrations of complexing agents. In some embodiments, the methods further include separating the graphene oxides that sorbed materials from the environment. Yet other embodiments may include desorbing the materials from the graphene oxides that sorbed the materials, and compositions therefrom.

1 . A method of radionuclide sequestration comprising: contacting substantially hydrophilic graphene oxides with a solution comprising a total initial concentration of one or more cationic radionuclides and a total initial concentration of one or more complexing agents, and
 reducing the total initial concentration of the one or more cationic radionuclides in the solution by at least forty percent by sorption of the one or more cationic radionuclides to at least a portion of the substantially hydrophilic graphene oxides.   
     
     
         2 . The method of  claim 1  wherein the total initial concentration of the one or more cationic radionuclides is equal to or less than 2.15×10 −7  M. 
     
     
         3 . The method of  claim 1 , wherein the solution comprises an aqueous solution. 
     
     
         4 . The method of  claim 1 , wherein the contacting comprises mixing the substantially hydrophilic graphene oxides with the solution. 
     
     
         5 . The method of  claim 1 , wherein the sorption comprises absorption. 
     
     
         6 . The method of  claim 1 , wherein the substantially hydrophilic graphene oxides are selected from the group consisting of functionalized graphene oxides, chemically converted graphene, pristine graphene oxides, doped graphene oxides, reduced graphene oxides, functionalized graphene oxide nanoribbons, pristine graphene oxide nanoribbons, doped graphene oxide nanoribbons, reduced graphene oxide nanoribbons, stacked graphene oxides, graphite oxides, and combinations thereof. 
     
     
         7 . The method of  claim 1 , wherein the one or more cationic radionuclides is selected from cations of the group consisting of thallium, iridium, fluorine, americium, neptunium, gadolinium, bismuth, uranium, thorium, plutonium, niobium, barium, cadmium, cobalt, europium, manganese, sodium, zinc, technetium, strontium, polonium, cesium, potassium, radium, lead, actinides, lanthanides and combinations thereof. 
     
     
         8 . The method of  claim 1 , further comprising adjusting the pH of the solution such that the reduction of the total initial concentration of the one or more cationic radionuclides occurs in about twenty minutes or less after contacting the substantially hydrophilic graphene oxides with the solution. 
     
     
         9 . The method of  claim 1 , wherein the total initial concentration of the one or more complexing agents in the solution is in the range of 2.4×10 4  times and 2.6×10 13  times the total initial concentration of the one or more cationic radionuclides. 
     
     
         10 . The method of  claim 1 , wherein the one or more complexing agents is selected from the group consisting of Na + , Ca 2+ , NO 3   − , CH 3 COO − , C 2 O 4   2− , SO 4   2− , Cl − , CO 3   2− , and combinations thereof. 
     
     
         11 . The method of  claim 1 , wherein the substantially hydrophilic graphene oxides have a ratio of total oxygen functionality to graphitic sp 2  carbon in the range of 2.6:1 and 4.0:1. 
     
     
         12 . The method of  claim 1 , further comprising separating the graphene oxides from the solution. 
     
     
         13 . The method of  claim 12 , wherein the separating comprises at least one of the following: centrifugation, ultra-centrifugation, filtration, ultra-filtration, precipitation, electrophoresis, reverse osmosis, sedimentation, incubation, treatment with acids, treatment with bases, treatment with chelating agents, and combinations thereof. 
     
     
         14 . The method of  claim 12 , wherein the separating comprises precipitating the graphene oxides from the solution by the addition of a polymer to the solution. 
     
     
         15 . The method of  claim 1 , wherein the one or more cationic radionuclides is a cationic actinide and the solution is comprised of nuclear fission products. 
     
     
         16 . The method of  claim 15 , further comprising separating the graphene oxides from the solution after the sorption. 
     
     
         17 . A method of radionuclide sequestration comprising: contacting substantially hydrophilic graphene oxides with a solution comprising nuclear fission products comprised of actinides, and reducing the concentration of the actinides in the solution by sorption of at least a portion of the actinides to the substantially hydrophilic graphene oxides. 
     
     
         18 . A method of radionuclide sequestration comprising: contacting substantially hydrophilic graphene oxides with a solution comprising one or more cationic radionuclides having a total initial cationic radionuclide concentration of 2.15×10 −7  M or less,
 the solution is additionally comprised of one or more complexing agents selected from the group consisting of Na + , Ca 2+ , NO 3   − , CH 3 COO − , C 2 O 4   2− , Cl − , SO 4   2− , Cl − , CO 3   2− , and combinations thereof; and 
 sorbing the one or more cationic radionuclides to at least a portion of the substantially hydrophilic graphene oxides. 
 
     
     
         19 . The method of  claim 18 , further comprising reducing the total initial concentration of the one more cationic radionuclides by at least forty percent in about twenty minutes or less after contacting the substantially hydrophilic graphene oxides. 
     
     
         20 . The method of  claim 18 , further comprising desorbing one or more of the radionuclides from the graphene oxides that sorbed the cationic radionuclides and separating the desorbed radionuclides from the graphene oxides to produce radionuclide-desorbed graphene oxides. 
     
     
         21 . The method of  claim 20 , further comprising repeating the method of  claim 20  at least once wherein the graphene oxides comprise the radionuclide-desorbed graphene oxides. 
     
     
         22 . A composition comprising radionuclide-sorbed graphene oxides prepared by the process of contacting substantially hydrophilic graphene oxides with a solution comprising one or more cationic radionuclides and one or more complexing agents,
 sorbing at least forty percent of the total initial concentration of the one or more cationic radionuclides to at least a portion of the substantially hydrophilic graphene oxides thereby producing radionuclide-sorbed graphene oxides,   separating the radionuclide-sorbed graphene oxides from the solution.   
     
     
         23 . A radionuclide composition prepared by the process of contacting substantially hydrophilic graphene oxides with a solution comprising one or more cationic radionuclides and one or more complexing agents,
 sorbing at least forty percent of the total initial concentration of the one or more cationic radionuclides to at least a portion of the substantially hydrophilic graphene oxides thereby producing radionuclide-sorbed graphene oxides,   separating the radionuclide-sorbed graphene oxides from the solution, and   desorbing one or more of the radionuclides from the radionuclide-sorbed graphene oxides.