TY - JOUR
T1 - Mechanism of boron uptake by hydrocalumite calcined at different temperatures
AU - Qiu, Xinhong
AU - Sasaki, Keiko
AU - Takaki, Yu
AU - Hirajima, Tsuyoshi
AU - Ideta, Keiko
AU - Miyawaki, Jin
N1 - Funding Information:
Financial support was provided to KS by Funding Program for Progress 100 (World Premier International Researcher Invitation Program) through the operating expense grants of the Ministry of Education, Culture, Sports, Science and Technology. This work was also partially supported by the New Energy and Industrial Technology Development Organization (NEDO) under the Innovative Zero-Emission Coal-Fired Power Generation Project.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/4/8
Y1 - 2015/4/8
N2 - Hydrocalumite (Ca-Al-layered double hydroxide (LDH)) was prepared and applied for the removal of borate. The properties of Ca-Al-LDH calcined at different temperatures were diverse, which affected the sorption density and mechanism of boron species. The sorption density increased with increase in calcined temperature and the sample calcined at 900°C (Ca-Al-LDH-900) showed the maximum sorption density in this work. The solid residues after sorption were characterized by 11B NMR, 27Al NMR, SEM, and XRD to investigate the sorption mechanism. Dissolution-reprecipitation was the main mechanism for sorption of borate in Ca-Al-LDH. For Ca-Al-LDH calcined at 300 and 500°C, regeneration occurred in a short time and the newly forming LDHs were decomposed to release Ca2+ ions and formed ettringite with borate. Two stages occurred in the sorption of boron by Ca-Al-LDH calcined at 900°C. In the first stage, boron species adsorbed on the alumina gel resulting from the hydration of calcined products. In this stage, borate was included as an interlayer anion into the newly forming LDHs in the following stage, and then immobilized as HBO32- into the interlayer, most the LDHs.
AB - Hydrocalumite (Ca-Al-layered double hydroxide (LDH)) was prepared and applied for the removal of borate. The properties of Ca-Al-LDH calcined at different temperatures were diverse, which affected the sorption density and mechanism of boron species. The sorption density increased with increase in calcined temperature and the sample calcined at 900°C (Ca-Al-LDH-900) showed the maximum sorption density in this work. The solid residues after sorption were characterized by 11B NMR, 27Al NMR, SEM, and XRD to investigate the sorption mechanism. Dissolution-reprecipitation was the main mechanism for sorption of borate in Ca-Al-LDH. For Ca-Al-LDH calcined at 300 and 500°C, regeneration occurred in a short time and the newly forming LDHs were decomposed to release Ca2+ ions and formed ettringite with borate. Two stages occurred in the sorption of boron by Ca-Al-LDH calcined at 900°C. In the first stage, boron species adsorbed on the alumina gel resulting from the hydration of calcined products. In this stage, borate was included as an interlayer anion into the newly forming LDHs in the following stage, and then immobilized as HBO32- into the interlayer, most the LDHs.
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U2 - 10.1016/j.jhazmat.2015.01.066
DO - 10.1016/j.jhazmat.2015.01.066
M3 - Article
C2 - 25661174
AN - SCOPUS:84922215847
VL - 287
SP - 268
EP - 277
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
ER -