A green route to synthesize layered double hydroxides

Abstract

This article demonstrates a green route for synthesis of Ca‐doped [Mg3Al(OH)8]Cl from a reaction of AlCl3·6H2O, Mg(OH)2, Ca(OH)2, and NH3·H2O in water, which produces only the desired solid product and a by‐product NH4Cl in the mother solution; therefore, they can be separated easily by filtration or centrifugation. Being carefully designed, enough NH4Cl can be crystallized from the mother solution, which could be used as a fertilizer; while the distilled water be used to wash the products for the last time; the mother solution that still contains some NH4Cl and filtrate from the first time washing of the product can be used to prepare the LDH again. By using cheaper Mg(OH)2 and Ca(OH)2 instead of MgCl2·6H2O and CaCl2·2H2O, the process is more economic and produces less NH4Cl. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 234–239, 2015

Production of added-value materials from a hazardous waste in the aluminium tertiary industry: Synergistic effect between hydrotalcites and glasses

“…In this sense, the influence of NH 4 Cl on the coprecipitation reaction was recently reported as a kinetic modifier, thus acting as a catalyst when Mg (OH) 2 and Ca(OH) 2 were used for the synthesis of hydrotalcites [39]. In this case the reactions took place at a constant pH 10.…”

Nanoporous Cu Prepared through Dealloying by Selectively Etching an Alkaline Metal with Saline

“…This passivates the Mg surface with Mg(OH) 2 , which is insoluble in water and hinders the rapid dissolution of Mg. In the saline solution, the ammonium ions remove the hydroxide layer, as shown by the reaction in eq , as follows: Mg false( OH false) 2 ( s ) + 2 normalN normalH 4 + → Mg 2 + + 2 normalN normalH 4 OH ( l ) and the weakly acidic saline solution (pH ∼ 5) accelerates the dealloying. These reactions do not produce any harmful chemical waste after fabrication.…”