Copper ions removal from aqueous solutions by novel Ca–Al–Zn layered double hydroxides

Abstract

Novel Ca–Al–Zn layered double hydroxide (LDH) was synthesized by co-precipitation method and its calcined product (calcined Ca–Al–Zn LDH) was obtained by heating at 450°C for 4.0 h. The calcined and uncalcined products of Ca–Al–Zn LDHs were used as adsorbents to remove copper ions from aqueous solutions. The structure, composition, and morphology of the synthesized calcined and uncalcined products were approved by X-ray diffraction, FT-IR, N₂ adsorption–desorption isotherm, and scanning electron microscopy. The removal capacities of calcined layered double hydroxide are higher than that of uncalcined LDH at ambient temperature, different pH, constant shaking rate 160 rpm, and different copper/adsorbent ratios. According to the analytical results and the experimental data, we were successful to prepare a novel LDH adsorbent for the Cu(II) removal, where the removal of the copper ions reached a maximum value at pH 6.0, shaking, 160 rpm, adsorbent mass 0.25 g/l and after 120 min to be 15.4 and 20.5 mg of Cu(II) per gram of uncalcined and calcined LDH, respectively. According to these results, the calcined Ca–Al–Zn LDH has higher potential application in Cu(II) ions removal field.

Keywords:

• Water treatment
• Ca–Al–Zn LDH
• Cu(II) removal
• Calcination