A magnesium-aluminum layered double hydroxide intercalated with NO 3 - (NO 3·Mg-Al LDH) removed Sb(V) in solution. The antimony (Sb) removal increased with time and with an increasing molar ratio of Al/Sb, i.e., the quantity of NO 3·Mg-Al LDH. The removal of Sb(V) in solution by NO 3·Mg-Al LDH was not due to the reaction of Sb(V) with dissolved Mg 2+ but was rather caused by anion exchange between Sb(V), i.e., Sb(OH) 6 -, in an aqueous solution and NO 3 - in the interlayer of the Mg-Al LDH. The intercalation of Sb(OH) 6 - in the interlayer ofMg-Al LDH is thought to result in the formation of a brandholzite-like structure. Some Sb(OH) 6 - was likely adsorbed on the surface of the NO 3·Mg-Al LDH. The efficiency of the Sb removal decreased in the following order, irrespective of the reaction time: NO 3·Mg-Al LDH ≈ Cl·Mg-Al LDH > SO 4·Mg-Al LDH > CO 3·Mg-Al LDH. The removal of Sb by SO 4·Mg-Al LDH and Cl·Mg-Al LDH was also caused by anion exchange between Sb(V), i.e., Sb(OH) 6 -, in an aqueous solution and SO 4 2- and Cl - in the interlayer of Mg-Al LDH, which formed a brandholzite-like structure due to the intercalation of Sb(OH) 6 - into the interlayer. In the case of SO 4·Mg-Al LDH, hydrogen bonds between the Mg-Al LDH-positive host layer and Sb(OH) 6 - were probably stronger than the electrostatic force of attraction between the Mg-Al LDH-positive host layer and SO 4 2-. The results suggested that Cl·Mg-Al LDH was as effective as NO 3·Mg-Al LDH for the treatment of Sb(V) in aqueous solutions.
|Number of pages||6|
|Journal||Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering|
|Publication status||Published - 2012 Jul 1|
- Anion exchange
- Magnesium-aluminum layered double hydroxide
ASJC Scopus subject areas
- Environmental Engineering