Kinetics of uptake of Cu2+ and Cd2+ by Mg–Al layered double hydroxides intercalated with citrate, malate, and tartrate

In this study, kinetics of the uptake of Cu2+ and Cd2+ by Mg–Al layered double hydroxides (Mg–Al LDHs) intercalated with citrate3− (C6H5O73−), malate2− (C4H4O52−), and tartrate2− (C4H4O62−) in the interlayer were examined. When the Mg–Al LDHs were added to Cu2+ and Cd2+ solutions of a constant pH of 5.0, the concentrations of Cu2+ and Cd2+ decreased with increasing temperature. The uptake was shown to occur as chelation between the heavy metal ions and the organic acid anions. The uptake rate equation was found to be dependent on the type of chelate formed.