Electrochemical Concentration of Lanthanide and Actinide Elements

Abstract

A carbon paste electrode is modified with a chemical agent that is selective for a plurality of lanthanides and actinides (f-series) elements. The modified carbon paste electrode selectively has different voltages applied thereto where a first voltage is used to cause the deposition of one or more lanthanides or actinides from an industrial or environmental sample onto the electrode, and, subsequent to removal of the electrode from the sample and insertion into a second sample where concentration of lanthanides or actinides is preferred, a second voltage is used to cause the deposited lanthanides and/or actinides to be discharged from the electrode for concentration into the second sample.

1 - 8 . (canceled) 
     
     
         9 . A retrieving and depositing method for retrieving one or more lanthanides or actinides from a first solution and depositing said one or more lanthanides or actinides in a second solution, comprising the steps of:
 contacting a first solution which contains one or more lanthanides or actinides with a modified carbon paste electrode comprised of an electrically conductive substrate with a carbon paste adhered to a surface Surfaces of said substrate and with one or modifying agents that selectively bind lanthanides or actinides dispersed within said carbon paste;   applying a first voltage to the modified carbon paste electrode suitable to deposit said one or more lanthanides or actinides contained in said sample onto the modified carbon paste electrode;   moving the modified carbon paste electrode to a second solution; and   applying a second voltage suitable to release of said one or more lanthanides or actinides into said second sample.   
     
     
         10 . The method of  claim 9  wherein said first solution is an environmental sample. 
     
     
         11 . The method of  claim 9  wherein said first solution is an industrial sample. 
     
     
         12 . The method of  claim 9  wherein said second solution is of a smaller volume than said first solution, wherein said steps of contacting, applying, moving, and applying concentrate said one or more lanthanides or actinides in said second solution. 
     
     
         13 . The method of  claim 9  wherein the modified paste electrode is repeatedly cycled between the first solution and said second solution, and said step of applying the first voltage is performed within the first solution and said step of applying the second voltage is performed within the second solution. 
     
     
         14 . The method of  claim 9  wherein the one or more modifying agents are selected from the group consisting of 1,2-dihydroxybenzene-3,5-disulfonic acid, 2-hydroxyisobutyric acid, trimetaphosphoric acid, trans-1,2-cyclohexylenedinitrilotetraacetic acid, 2-hydroxy-2-methylpropanoic acid, iminodiacetic acid, nitrilotriacetic acid, ethylenedinitrilotetraacetic acid, diethylenetriamine-pentacetic acid, 2,2′,2″,2′″-(1,4,7,10tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid, N-(2-carboxyphenyl)iminodiacetic acid, dihydroxycyclobutenedione, 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid and derivatives of these compounds. 
     
     
         15 . The method of  claim 14  wherein the one or more modifying agents are reduced by said step of applying said first voltage and wherein said chemical agent is in a ground state by said step of applying said second voltage. 
     
     
         16 . The method of  claim 9  wherein the first voltage ranges from −0.05 to −0.05 V and wherein the second voltage ranges from 0.1 to 0.09 V. 
     
     
         17 . A method of selectively binding lanthanides and/or actinides in a sample, comprising:
 inserting in a sample containing one or more lanthanides or actinides a carbon paste electrode comprising an electrically conductive substrate, a carbon paste adhered to a surface of the substrate, and one or more modifying agents dispersed within said carbon paste, wherein at least one of said modifying agents includes an organic group and binds to a plurality of lanthanide and/ or actinide elements; and   applying a voltage to the carbon paste electrode sufficient to reduce the organic group of the one or more modifying agents from its electrochemical ground state or oxidized state.   
     
     
         18 . The method of  claim 17  wherein said one or more modifying agents are selected from the group consisting of 1,2-dihydroxybenzene-3,5-disulfonic acid, 2-hydroxyisobutyric acid, trimetaphosphoric acid, trans-1,2-cyclohexylenedinitrilotetraacetic acid, 2-hydroxy-2-methylpropanoic acid, iminodiacetic acid, nitrilotriacetic acid, ethylenedinitrilotetraacetic acid, diethylenetriamine-pentacetic acid, 2,2′,2″,2′″-(1,4,7,10tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid, N-(2-carboxyphenyl)iminodiacetic acid, dihydroxycyclobutenedione, 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid and derivatives of these compounds, and wherein said applying step applies a negative voltage. 
     
     
         19 . The method of  claim 17  wherein said one or more modifying agents are selected from the group consisting of 1,2-dihydroxybenzene-3,5-disulfonic acid, 2-hydroxyisobutyric acid, trimetaphosphoric acid, trans-1,2-cyclohexylenedinitrilotetraacetic acid, 2-hydroxy-2-methylpropanoic acid, nitrilotriacetic acid, diethylenetriamine-pentacetic acid, 2,2′,2″,2′″-(1,4,7,10tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid, N-(2-carboxyphenyl)iminodiacetic acid, dihydroxycyclobutenedione, 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid and derivatives of these compounds, and wherein said applying step applies a negative voltage. 
     
     
         20 . A system for selectively binding lanthanides and/or actinides in a sample, comprising:
 a carbon paste electrode configured to be inertable in a sample containing one or more lanthanides or actinides, the carbon paste electrode comprising an electrically conductive substrate, a carbon paste adhered to a surface of the substrate, and one or more modifying agents dispersed within said carbon paste, wherein at least one of said modifying agents includes an organic group and binds to a plurality of lanthanide and/ or actinide elements; and   a voltage source electrically connected to the carbon past electrode configured for applying a voltage to the carbon paste electrode sufficient to reduce the organic group of the one or more modifying agents from its electrochemical ground state or oxidized state.   
     
     
         21 . The system of  claim 20  wherein said one or more modifying agents are selected from the group consisting of 1,2-dihydroxybenzene-3,5-disulfonic acid, 2-hydroxyisobutyric acid, trimetaphosphoric acid, trans-1,2-cyclohexylenedinitrilotetraacetic acid, 2-hydroxy-2-methylpropanoic acid, iminodiacetic acid, nitrilotriacetic acid, ethylenedinitrilotetraacetic acid, diethylenetriamine-pentacetic acid, 2,2′,2″,2′″-(1,4,7,10tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid, N-(2-carboxyphenyl)iminodiacetic acid, dihydroxycyclobutenedione, 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid and derivatives of these compounds, and wherein the voltage source applies a negative voltage. 
     
     
         22 . The system of  claim 20  wherein said one or more modifying agents are selected from the group consisting of 1,2-dihydroxybenzene-3,5-disulfonic acid, 2-hydroxyisobutyric acid, trimetaphosphoric acid, trans-1,2-cyclohexylenedinitrilotetraacetic acid, 2-hydroxy-2-methylpropanoic acid, nitrilotriacetic acid, diethylenetriamine-pentacetic acid, 2,2′,2″,2′″-(1,4,7,10tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid, N-(2-carboxyphenyl)iminodiacetic acid, dihydroxycyclobutenedione, 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecane-1,14-dioic acid and derivatives of these compounds, and wherein the voltage source applies a negative voltage.