Competitive adsorption of gold ion in the presence of Fe(III) species on Mg/Al layered double hydroxides

Abstract

In this paper, Mg/Al layered double hydroxide (LDH) was prepared via the co-precipitation method and used as an adsorbent of gold (AuCl4 −) with Fe3+ as the competitor ion in the aqueous solution. We conducted an adsorption test for single (without competitor) and binary (presence competitor) solutions. The adsorbent was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Field emission scanning electron microscopy (FE-SEM). The effect of solution acidity indicated that the optimum adsorption of AuCl4 − without competitor was at pH 3. The kinetic study revealed that the adsorbent followed pseudo-second-order with a rate constant (k) of 2.88 x 10−3 and 3.92 x 10−3 g/(mg.min) for the single and binary solutions, respectively. According to the Langmuir isotherm model, the adsorption capacity was 21.74 and 14.29 mg g−1 for single and binary solutions, respectively. The morphological characteristic of the adsorbent showed the layered structure with the hexagonal platelet-type images.