JP2007296463A5

JP2007296463A5 -

Info

Publication number: JP2007296463A5
Application number: JP2006126029A
Authority: JP
Filing date: 2006-04-28
Publication date: 2009-06-18
Anticipated expiration: 2026-04-28

Description

本発明は、以下に示す構成によって上記課題を解決したヒドロキシアパタイトシリカ複合体多孔質吸着剤とその製造方法に関する。
〔１〕結晶質ヒドロキシアパタイトと多孔質シリカとの複合体からなり、カルシウムとリンのモル比（Ｃａ/Ｐ）が１.９未満であることを特徴とするヒドロキシアパタイトシリカ複合多孔質体吸着剤。
〔２〕通液６０分経過後の残留Ｐｂ濃度が０.２５ppm以下である上記[１]に記載するヒドロキシアパタイトシリカ複合多孔質体吸着剤。
〔３〕カルシウムとリンのモル比（Ｃａ/Ｐ）が１.３を上回り〜１.６７以下であり、カルシウム溶解度２.６９以下である上記[１]または上記[２]に記載するヒドロキシアパタイトシリカ複合多孔質体吸着剤。
〔４〕全細孔容積０.５ml/g以上、透水率１〜１００×１０^-4cm/s、平均粒径１０〜６０μm、ＢＥＴ比表面積１００m²/g以上である上記[１]〜上記[３]の何れかに記載するヒドロキシアパタイトシリカ複合多孔質体吸着剤。
〔５〕 (Ｃａ/Ｓｉ)モル比が０.１〜２.０の珪酸カルシウム化合物に、(Ｃａ/Ｐ)モル比が１.９未満である量のリン酸を加えることにより、珪酸カルシウム化合物のカルシウム分を結晶質ヒドロキシアパタイトに転化させると共に、シリカ分を多孔質シリカに転化させ、(Ｃａ/Ｐ)モル比が１.９未満のヒドロキシアパタイトシリカ複合多孔質を製造することを特徴とする製造方法。
〔６〕ｐＨ７.０以上になるようにリン酸を徐々に添加し、０.５時間〜１２時間反応させる請求項５に記載する製造方法。
〔７〕珪酸カルシウムスラリーまたは珪酸カルシウム化合物を温水に浸漬したものに、(Ｃａ/Ｐ)モル比が１.９未満である量のリン酸を加温下で撹拌しながら、ｐＨ７.０以上になるようにリン酸を徐々に添加して０.５時間〜１２時間反応させ、ヒドロキシアパタイトシリカ複合多孔質体を製造する上記[５]〜上記[６]の何れかに記載する製造方法。
〔８〕珪酸カルシウム化合物にまず酸を反応させて珪酸カルシウム化合物のカルシウムを部分的に溶解除去し、次いでリン酸を反応させて結晶質ヒドロキシアパタイトを生成させてヒドロキシアパタイトシリカ複合多孔質体を製造する上記[５]〜上記[７]の何れかに記載する製造方法。
The present invention relates to a hydroxyapatite silica composite porous adsorbent and a method for producing the same, which have solved the above-described problems with the following configuration.
[1] Hydroxyapatite silica composite porous material adsorbent comprising a composite of crystalline hydroxyapatite and porous silica, wherein the molar ratio of calcium to phosphorus (Ca / P) is less than 1.9 .
[2] The hydroxyapatite silica composite porous material adsorbent according to the above [1], wherein the residual Pb concentration after passage of 60 minutes is 0.25 ppm or less.
[3] Hydroxyapatite according to [1] or [2] above, wherein the molar ratio of calcium to phosphorus (Ca / P) is more than 1.3 to 1.67 or less and calcium solubility is 2.69 or less. Silica composite porous material adsorbent.
[4] The above-mentioned [1] -above having a total pore volume of 0.5 ml / g or more, a water permeability of 1-100 × 10 ⁻⁴ cm / s, an average particle size of 10-60 μm, and a BET specific surface area of 100 m ² / g or more. The hydroxyapatite silica composite porous material adsorbent according to any one of [3].
[5] Calcium silicate compound by adding an amount of phosphoric acid having a (Ca / P) molar ratio of less than 1.9 to a calcium silicate compound having a (Ca / Si) molar ratio of 0.1 to 2.0 The calcium content is converted to crystalline hydroxyapatite and the silica content is converted to porous silica to produce a hydroxyapatite silica composite porous material having a (Ca / P) molar ratio of less than 1.9. Production method.
[6] The production method according to claim 5, wherein phosphoric acid is gradually added so as to have a pH of 7.0 or more, and the reaction is performed for 0.5 hours to 12 hours .
[7] While the calcium silicate slurry or the calcium silicate compound is immersed in warm water, the amount of phosphoric acid having a (Ca / P) molar ratio of less than 1.9 is stirred while heating to a pH of 7.0 or higher. The production method according to any one of [5] to [6] above, wherein phosphoric acid is gradually added and reacted for 0.5 to 12 hours to produce a hydroxyapatite silica composite porous body.
[8] Calcium silicate compound is first reacted with acid to partially dissolve and remove calcium of calcium silicate compound, then phosphoric acid is reacted to produce crystalline hydroxyapatite to produce a hydroxyapatite silica composite porous body The manufacturing method according to any one of [5] to [7] above.

一方、本発明の製造方法では、ヒドロキシアパタイトの生成と共に多孔質なシリカが生成するので、多孔性を損なうことなく、ヒドロキシアパタイトと多孔質シリカとの複合体が形成される。また、珪酸カルシウム化合物とリン酸との反応方法を工夫することにより、珪酸カルシウム化合物の酸分解により生じる多孔質シリカを、もとの珪酸カルシウム化合物粒子から遊離させず、その粒子表面にヒドロキシアパタイトと同時に析出させることによって、良好な濾過性、沈降性、透水性を有する複合多孔質体を得ることができる。さらに、本発明の製造方法によって生成するヒドロキシアパタイトは結晶性が良いため、水に対する溶解性も低いという利点を有する。
On the other hand, in the production method of the present invention, porous silica is generated together with the generation of hydroxyapatite, so that a composite of hydroxyapatite and porous silica is formed without impairing the porosity. In addition, by devising a reaction method between the calcium silicate compound and phosphoric acid, the porous silica generated by acid decomposition of the calcium silicate compound is not released from the original calcium silicate compound particles, and hydroxyapatite and By depositing at the same time, a composite porous body having good filterability , sedimentation and water permeability can be obtained. Furthermore, since the hydroxyapatite produced by the production method of the present invention has good crystallinity, it has an advantage of low solubility in water.

以下、本発明の製造方法を具体的に説明する。
本発明のヒドロキシアパタイトシリカ複合体の基材となる珪酸カルシウムは、珪酸原料と石灰原料とを水性スラリーとしたものを、例えば、オートクレーブ中において水熱反応（実施例１〜９ではオートクレーブ中、１８０℃〜２２０℃の水熱反応）を行なって合成した一般的によく知られているものを好適に用いることができる。その種類としては、珪酸カルシウム化合物であれば特に限定されず、例えば、トバモライト、ジャイロライト、ゾノトライトなどの結晶質珪酸カルシウム、あるいは非晶質珪酸カルシウムなど何れの珪酸カルシウムも用いることができる。これらは単独で用いても良いし、２種以上を組み合わせて用いても良い。また、これらの珪酸カルシウム化合物は粉体の状態だけではなく、これらの珪酸カルシウム化合物を適当な方法で成型した板状物あるいは塊状物を用いることができる。
Hereinafter, the production method of the present invention will be specifically described.
The calcium silicate used as the base material of the hydroxyapatite silica composite of the present invention is obtained by hydrothermal reaction in an autoclave (for example, in the autoclave in Examples 1-9, 180) A generally well-known one synthesized by carrying out a hydrothermal reaction between ℃ and 220 ℃ can be suitably used. As the kind is not particularly limited as long as it is a calcium silicate compound, for example, tobermorite, gyro light, can be used crystalline calcium silicate or any calcium silicate such as amorphous calcium silicate, such as xonotlite. These may be used alone or in combination of two or more. These calcium silicate compounds can be used not only in the form of powder, but also in the form of plates or lumps obtained by molding these calcium silicate compounds by an appropriate method.

本発明のヒドロキシアパタイトシリカ複合体の基材となる珪酸カルシウムは、実施例１〜１０に示すように、カルシウムとシリカのモル比（Ｃａ/Ｓｉ）が０.１〜２.０であるものが好ましく、０.４〜０.８のものがより好ましい。カルシウムとシリカのモル比（Ｃａ/Ｓｉ）が上記範囲であるものは、丸味を帯びた粒子形になり、透水性の良い多孔質複合体を得ることができる。
As shown in Examples 1 to 10, the calcium silicate used as the base material of the hydroxyapatite silica composite of the present invention has a calcium to silica molar ratio (Ca / Si) of 0.1 to 2.0. Preferably, the thing of 0.4-0.8 is more preferable. When the molar ratio of calcium to silica (Ca / Si) is in the above range, the particles are rounded and a porous composite with good water permeability can be obtained.

図１に示すように、比較例３、４、６では２０分経過後のＰｂ濃度は何れも２０ppm以上であるが、本発明の実施例１、３、７、８、９、１０は何れも１０分経過後には１０ppm以下、２０分経過後のＰｂ濃度は実質的にゼロであり、重金属に対して短時間に優れた吸着効果を有することが判る。この傾向は図２においても同様であり、ヒドロキシアパタイトのカルシウムとリンのモル比（Ｃａ/Ｐ）が１.９０である比較例１は６０分経過後のＰｂ濃度が４０ppm以上であるのに対して、本発明の実施例１、５、６は２０分経過後のＰｂ濃度は実質的にゼロであり、優れた吸着効果を有している。具体的には、表１に示すように、(Ｃａ/Ｐ)モル比１.９０の比較例１（No.21）は通液６０分経過後のＰｂ濃度は４４.３ppmであるが、(Ｃａ/Ｐ)モル比１.６７以下の実施例１〜１０は通液６０分経過後のＰｂ濃度は何れも０.２５ppm以下であり比較例１〜３より低い。また、実施例１〜１０の蛋白質吸着率は何れも５３.５％以上であり、比較例１〜３および市販品より大幅に高い。なお、比較例２（No.22）はリン酸量が(Ｃａ/Ｐ)モル比１.６７であるが、リン酸の反応時間が２分間であるため、通液６０分経過後のＰｂ濃度０.３９ppmおよび蛋白質吸着３５.６％であり、何れも実施例１〜１０よりかなり低い。さらに、比較例３（No.23）はコンクリート廃材をリン酸中に浸漬して表面をヒドロキシアパタイト化したものであり、通液６０分経過後のＰｂ濃度および蛋白質吸着は何れも実施例１〜１０よりかなり低い。
As shown in FIG. 1, in Comparative Examples 3, 4, and 6, the Pb concentration after 20 minutes is 20 ppm or more, but in Examples 1, 3, 7, 8, 9, and 10 of the present invention, After 10 minutes, 10 ppm or less, and the Pb concentration after 20 minutes is substantially zero, indicating that the heavy metal has an excellent adsorption effect in a short time. This tendency is the same in FIG. 2, whereas in Comparative Example 1 in which the molar ratio of calcium to phosphorus (Ca / P) of hydroxyapatite is 1.90, the Pb concentration after 60 minutes is 40 ppm or more. In Examples 1, 5, and 6 of the present invention, the Pb concentration after 20 minutes is substantially zero, and has an excellent adsorption effect. Specifically, as shown in Table 1, Comparative Example 1 (No. 21) having a (Ca / P) molar ratio of 1.90 has a Pb concentration of 44.3 ppm after passage of 60 minutes. In Examples 1 to 10 having a Ca / P) molar ratio of 1.67 or less, the Pb concentration after passing through the liquid for 60 minutes is 0.25 ppm or less, which is lower than those of Comparative Examples 1 to 3. Moreover, all the protein adsorption rates of Examples 1-10 are 53.5% or more, and are significantly higher than Comparative Examples 1-3 and a commercial item. In Comparative Example 2 (No. 22), the amount of phosphoric acid was (Ca / P) molar ratio 1.67, but the reaction time of phosphoric acid was 2 minutes, so the Pb concentration after 60 minutes passed through 0.39 ppm and protein adsorption 35.6%, both of which are considerably lower than in Examples 1-10. Further, Comparative Example 3 (No. 23) was obtained by dipping concrete waste material in phosphoric acid to make the surface hydroxyapatite. Both the Pb concentration and the protein adsorption after 60 minutes passed were in Examples 1 to 3. Much lower than 10.

〔図１〕実施例および比較例について、経過時間によるＰｂ濃度を示すグラフ
〔図２〕実施例および比較例について、経過時間によるＰｂ濃度を示すグラフ
〔図３〕実施例１の本発明試料について、Ｘ線回折結果を示すグラフ
[Fig. 1] Graph showing Pb concentration by elapsed time for Example and Comparative Example [Fig. 2] Graph showing Pb concentration by elapsed time for Example and Comparative Example [Fig. 3] Sample of the present invention of Example 1 , Graph showing X-ray diffraction results

Claims

A hydroxyapatite silica composite porous material adsorbent comprising a composite of crystalline hydroxyapatite and porous silica, wherein the molar ratio of calcium to phosphorus (Ca / P) is less than 1.9 .

The hydroxyapatite silica composite porous material adsorbent according to claim 1, wherein the residual Pb concentration after passage of 60 minutes is 0.25 ppm or less .

The hydroxyapatite silica composite porous body according to claim 1 or 2, wherein the molar ratio of calcium to phosphorus (Ca / P) is more than 1.3 to 1.67 or less and calcium solubility is 2.69 or less. Adsorbent.

The total pore volume is 0.5 ml / g or more, the water permeability is 1 to 100 × 10 ⁻⁴ cm / s, the average particle size is 10 to 60 μm, and the BET specific surface area is 100 m ² / g or more. A hydroxyapatite silica composite porous material adsorbent as described above.

By adding an amount of phosphoric acid having a (Ca / P) molar ratio of less than 1.9 to a calcium silicate compound having a (Ca / Si) molar ratio of 0.1 to 2.0, the calcium content of the calcium silicate compound is increased. And a hydroxyapatite-silica composite porous material having a (Ca / P) molar ratio of less than 1.9, wherein the silica content is converted to crystalline hydroxyapatite and the silica content is converted to porous silica.

The production method according to claim 5, wherein phosphoric acid is gradually added so as to have a pH of 7.0 or more, and the reaction is carried out for 0.5 to 12 hours .

To a solution in which calcium silicate slurry or calcium silicate compound is immersed in warm water, the amount of phosphoric acid having a (Ca / P) molar ratio of less than 1.9 is stirred under heating so that the pH becomes 7.0 or higher. The production method according to any one of claims 5 to 6, wherein a hydroxyapatite silica composite porous body is produced by gradually adding phosphoric acid and reacting for 0.5 to 12 hours.

A method for producing a hydroxyapatite silica composite porous body by first reacting a calcium silicate compound with an acid to partially dissolve and remove calcium of the calcium silicate compound, and then reacting phosphoric acid to produce crystalline hydroxyapatite. The manufacturing method in any one of Claims 5-7.