Solid layer double hydroxides (LDHs) are promising adsorbents for heavy metal and rare earth element
removal from aqueous streams. LDHs are layered materials that are built of positively charged brucite-like
layers weakly bound with each other by exchangeable anions. LDHs are typically synthetically made and have
positively charged layers that contain different bivalent cations (Mg, Mn, Zn, Cu, Ni, etc.) and trivalent cations
(Al, Fe, Cr, etc.), but can also be formed in clay mineral silicates like kaolinite. These materials have been used
in waste water treatment and in soil remediation to capture heavy metal ions. Additionally, these materials can
be intercalated with different organic molecules to form organic-inorganic hybrid materials that can be used as
sorbents. Specifically, LDHs can be intercalated with chelating anions in the interlayer space to enhance
sorption properties of the materials. Studies on decontamination of aqueous media from U(VI), and sorption of
Cu2+, Cd2+, and Pb2+ reported the use of inorganic hydrotalcite sorbents and LDHs.
In this study a hydrotalcite material was synthesized and compared to a layered double hydroxide
intercalated with ethylenediaminetetracetic acid (EDTA). The materials were fully characterized using various
characterization techniques including SEM, XRD, and BET. The material was then tested for extraction of rare
earth elements from a synthetic ideal aqueous solution. Parameters such as the pH, and the LDH to water ratio
were varied to see the effects on extraction efficiency for the materials. The rare earth element concentration
was measured using ICP-MS.