Method for producing adsorbent, adsorbent, and adsorption apparatus
A method for producing an adsorbent which is stable toward a liquid such as an eluant and which shows excellent reproducibility in selectively adsorbing and separating an object compound, the method includes the steps of: preparing a base material having a surface, in which at least part of the surface of the base material is formed of a material containing as its major component apatite which is represented by the composition formula Ca 10 (PO 4 ) 6 ((OH) 1-a X a ) 2 ; preparing a solution containing ions of at least one metal element; substituting at least part of Ca of the apatite by the at least one metal element by bringing the base material into contact with the solution to obtain a substituted base material; and subjecting the substituted base material to heat treatment at 50 to 400° C. for 0.5 to 10 hours, wherein the base material and the substituted base material are not exposed to a temperature exceeding 500° C. for 4 hours or longer from the substitution step to the completion of production of the adsorbent.
1. A method for producing an adsorbent capable of selectively adsorbing an object compound, the method comprising:
preparing a base material having a surface, in which at least part of the surface of the base material is formed of a material containing as its major component apatite which is represented by the composition formula Ca 10 (PO 4 ) 6 ((OH) 1-a X a ) 2 , where X represents at least one halogen element and 0≦a≦1;
preparing a solution comprising ions of at least one metal element, wherein said metal element is at least one of a bivalent metal element, a trivalent metal element, a lanthanoid metal element, or an actinoid metal element;
substituting at least part of the Ca of the apatite with the at least one metal element by bringing the base material into contact with the solution to obtain a substituted base material; and
subjecting the substituted base material to heat treatment at 50 to 400° C. for 0.5 to 10 hours,
wherein the heat treatment comprises a first heat treatment step carried out at a temperature of 50 to 250° C., and a second heat treatment step carried out at a temperature higher than that of the first heat treatment step, wherein the difference in a temperature between the first heat treatment step and the second heat treatment step is 50° C. or higher and
wherein the base material and the substituted base material are not exposed to a temperature exceeding 500° C. for 4 hours or longer from the time of substituting at least a part of the Ca to the completion of production of the adsorbent.
2. The method for producing an adsorbent as claimed in claim 1 , wherein the apatite is represented by the composition formula Ca 10 (PO 4 ) 6 (OH) 2 , the method further comprising:
preparing a solution containing ions of at least one halogen element, and
wherein at least part of the Ca of the apatite is substituted by the at least one metal element and at least part of the OH groups of the apatite are substituted by the at least one halogen element by bringing the base material into contact with the two solutions sequentially or almost simultaneously.
3. The method for producing an adsorbent as claimed in claim 1 , wherein the heat treatment is carried out in an oxidative atmosphere.
4. The method for producing an adsorbent as claimed in claim 1 , wherein a substitution amount of the Ca of the apatite with the at least one metal element is 0.01 wt % or higher.
5. The method for producing an adsorbent as claimed in claim 1 , wherein a substitution ratio of the OH groups of the apatite with the at least one halogen element is 30% or higher.