Mg–Al Hydrotalcites Intercalated by Ethylenediaminetetraacetic Acid for Ni(II) Removal from Aqueous Solution

High-efficient-adsorbents-layered double hydroxides (LDH) intercalated by carbonate ion and ethylenediaminetetraacetic acid (EDTA) ion were synthesized by the coprecipitation method for the removal of Ni2+ in the aqueous solution. MgAl–EDTA–LDH had a better adsorption performance than MgAl–CO3–LDH due to the larger specific surface area and strong trapping for heavy metal ions of EDTA. Ni(II) adsorption on the two kinds of LDH conformed to the pseudo-second-order kinetic model. The Langmuir isothermal adsorption model was more suitable to describe the adsorption isotherm than the Freundlich model. The maximum adsorption capacity of MgAl–EDTA–LDH and MgAl–CO3–LDH for Ni(II) was 108.2 and 23.47 mg/g, respectively. This work may offer ideas for the preparation and application of excellent adsorbents in the heavy metal removal from polluted water.