Decarbonation of MgAl-LDHs (layered double hydroxides) using acetate-buffer/NaCl mixed solution
Decarbonation of MgAl-LDHs (layered double hydroxides) using acetate-buffer/NaCl mixed solution
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DOI：
10.1016/j.jcis.2008.02.047
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发表时间：
2008-06-01
影响因子：
9.9
通讯作者：
Sasaki, Takayoshi
中科院分区：
文献类型：
--
作者：
Iyi, Nobuo;Sasaki, Takayoshi
采用醋酸盐缓冲液（醋酸钠和醋酸）/NaCl混合溶液，研究了不同Mg/Al比的MgAl-LDH对碳酸根离子（CO 32-）的脱嵌作用。当仅使用乙酸盐缓冲溶液时，即使使缓冲溶液足够酸性以溶解LDH本身，也不发生脱碳酸作用;然而，向缓冲溶液中加入NaCl导致碳酸根离子从MgAl-LDH脱嵌，并且在25 ℃下进行反应而没有任何形态和重量变化。在最佳条件下，两种MgAl-LDHs均能在min内完全脱碳，且由于其对乙酸根离子的选择性极低，所得LDHs层间含有Cl-，没有引入任何乙酸根阴离子。脱碳酸溶液的浓度的允许范围宽，并且由于缓冲作用，由脱碳酸反应引起的pH变化很小。脱碳酸作用受LDH的Mg/Al比的影响;即，本发明的LDH 2比LDH 3稍微更难分解，这可能是由于LDH 2的层电荷密度更高。(c)2008年爱思唯尔公司All rights reserved.
By using acetate-buffer (sodium acetate and acetic acid)/NaCl mixed solutions, the deintercalation of carbonate ions (CO32-) was conducted on MgAl-LDHs at different Mg/Al ratios-LDH2 (LDH with Mg/Al approximate to 2) and LDH3 (LDH with Mg/Al approximate to 3). When only an acetate-buffer solution was used, decarbonation did not take place even if the buffer solution was made acidic enough to dissolve LDH itself; however, the addition of NaCl to the buffer solution caused deintercalation of the carbonate ions from the MgAl-LDHs and the reaction was conducted without any morphological and weight change at 25 degrees C. Under the optimum conditions, full decarbonation was attained for the two MgAl-LDHs in minutes, and the obtained LDHs contained Cl- in the interlayer space without incorporation of any acetate anions due to their extremely low anion selectivity of acetate ion. The allowable range for the concentration of the decarbonation solution is wide, and the change in pH due to the decarbonation reaction is slight because of the buffering effect. The decarbonation was affected by the Mg/Al ratio of the LDH; i.e., the present LDH2 was slightly more difficult to decarbonate than LDH3, probably due to the higher layer-charge density of LDH2. (c) 2008 Elsevier Inc. All rights reserved.