Synthesis of Li-Al-carbonate layered double hydroxide in a metal salt-free system

• Published in: Journal of materials chemistry Vol. 2; no. 31; pp. 6524 - 653
• Main Authors: Lin, Meng-Chang, Chang, Fu-Tsung, Uan, Jun-Yen
• Format: Journal Article
• Language: English
• Published: 21.08.2010
• Subjects: Aluminum; Aqueous solutions; Drinking water; Flakes; Fluorides; Hydroxides; Nanostructure; Temperature
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/c0jm00710b

This work describes a novel method based on a metal salt-free system to synthesize a Li-Al-CO 3 layered double hydroxide (LDH) by simply adding powdered AlLi intermetallic compound (IMC) to a stirred water-bath at ambient temperature and atmosphere. The AlLi powder in the water-bath hydrolyzed strongly, subsequently forming an alkaline Al 3+ - and Li + -containing aqueous solution of pH 12.3. Additionally, dissolution of CO 2 gas from the ambient atmosphere into the stirred alkaline solution produced the anion, CO 3 2− , in the solution to form Li-Al-CO 3 LDH. Washing in water was unnecessary because metal salts were not used to synthesize the LDH. Notably, transmission electron microscopy (TEM) results indicate that nano-sized Al particles were incorporated on the surface of Li-Al-CO 3 LDH flakes. Chemical analysis data suggest that the chemical formula of Li-Al-CO 3 LDH was Li 0.33 Al 0.67 (CO 3 ) 0.17 (OH) 2 · m H 2 O. This work also investigates the removal of the fluoride ions from an aqueous solution by using Li-Al-CO 3 LDH. Experimentally, residual fluoride concentration decreased to 0.4 ppm with an initial concentration of 20 ppm, which satisfies World Health Organization (WHO) guidelines for drinking water quality. A novel method, based on a metal salt-free system, was explored for producing Li-Al-CO 3 LDH by simply adding powdered AlLi intermetallic compound (AlLi IMC) to a stirred water bath at ambient temperature and atmosphere.