Synthesis of Mg/Al–NO 3 hydrotalcite immobilized by citric acid for [AuCl 4 ]– adsorption

Synthesis of Mg/Al–NO 3 hydrotalcite immobilized by citric acid (Mg/Al–NO 3 HT–Cit) was synthesized for [AuCl 4 ]– adsorption. The Mg/Al–NO 3 HT–Cit was prepared by co-precipitation method. Optimum condition for the synthesis was studied by determining the optimum acidity and concentration of precursors. Application of adsorbent for [AuCl 4 ]– adsorption was studied by determining their kinetics model. The results showed that the optimum acidity for Mg/Al–NO 3 HT–Cit preparation was pH 7. The XRD diffractogram showed that synthesis of Mg/Al–NO 3 HT– Cit was successfully immobilized onto the surface of hydrotalcite with basal spacing d(003) was 7.99 Å. Adsorption of [AuCl 4 ]– was optimum at pH 3. Isotherm analysis revealed the adsorption of [AuCl 4 ]– is best fitted by Langmuir model with qmax value of 126.58 mg g⁻¹.