TY - JOUR
T1 - Removal mechanism of polymeric borate by calcined layered double hydroxides containing different divalent metals
AU - Xinhong, Qiu
AU - Sasaki, Keiko
N1 - Funding Information:
Financial support was provided to KS by Funding Program for Progress 100 in Kyushu University and this work was also supported by Natural Science Foundation of Hubei Province (No. 2015CFB506 ).
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015
Y1 - 2015
N2 - The removal mechanism of polymeric borate by calcined layered double hydroxides is not clear. In this work, layered double hydroxides containing different divalent metals were synthesized and calcined to produce calcined layered double hydroxides (Zn-, Mg-, and Ca-CLDH). Then, Zn-, Mg-, and Ca-CLDH were applied to remove polymeric borate. Zn-CLDH showed better performance for the removal of borate than Ca-CLDH, and hardly any borate was removed by Mg-CLDH. Based on the characterization results, the detailed removal process of polymeric borate by different calcined layered double hydroxides is discussed. Because there is little H3BO3 that can act as a trigger, and ligand promoted dissolution of the complex H3BO3 and MgO is prevented. Therefore, Mg-CLDH could not transform to the layered structure to immobilize the borate. For the Zn-CLDH, Zn-CLDH transformed into Zn-LDH, and polymeric borate was absorbed into the interlayer of layered double hydroxides, which is the dominant mechanism of borate removal by Zn-CLDH. Reconstruction of the Ca-LDH from the Ca-CLDH was more rapid than the other calcined layered double hydroxides. However, formation of borate-containing ettringite was the main removal mechanism in the first stage. With increasing reaction time, the reaction between CO32- and Ca2+ released from ettringite, and the regeneration of Ca-LDH to form CaCO3 were the main reasons for borate removal in the second stage.
AB - The removal mechanism of polymeric borate by calcined layered double hydroxides is not clear. In this work, layered double hydroxides containing different divalent metals were synthesized and calcined to produce calcined layered double hydroxides (Zn-, Mg-, and Ca-CLDH). Then, Zn-, Mg-, and Ca-CLDH were applied to remove polymeric borate. Zn-CLDH showed better performance for the removal of borate than Ca-CLDH, and hardly any borate was removed by Mg-CLDH. Based on the characterization results, the detailed removal process of polymeric borate by different calcined layered double hydroxides is discussed. Because there is little H3BO3 that can act as a trigger, and ligand promoted dissolution of the complex H3BO3 and MgO is prevented. Therefore, Mg-CLDH could not transform to the layered structure to immobilize the borate. For the Zn-CLDH, Zn-CLDH transformed into Zn-LDH, and polymeric borate was absorbed into the interlayer of layered double hydroxides, which is the dominant mechanism of borate removal by Zn-CLDH. Reconstruction of the Ca-LDH from the Ca-CLDH was more rapid than the other calcined layered double hydroxides. However, formation of borate-containing ettringite was the main removal mechanism in the first stage. With increasing reaction time, the reaction between CO32- and Ca2+ released from ettringite, and the regeneration of Ca-LDH to form CaCO3 were the main reasons for borate removal in the second stage.
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U2 - 10.1016/j.colsurfa.2015.07.036
DO - 10.1016/j.colsurfa.2015.07.036
M3 - Article
AN - SCOPUS:84938149386
SN - 0927-7757
VL - 482
SP - 702
EP - 709
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
ER -