Adsorption of Cd(II) on Zn-Al LDHs (Layered Double Hydroxides) Intercalated with Chelating Agents EDTA

Abstract

Abstract:The hydrotalcite-like compound [Zn 2 Al(OH) 6 ]NO 3 ·mH 2 O (shorted as ZnAl-NO 3 ) was intercalated with the chelating agent EDTA (ethylene diamine tetraacetic acid) by anion exchange to uptake cadmium ion from aqueous solutions. The materials synthesized in this work were characterized by chemical analysis, FT-IR (fourier transform infrared spectroscopy), XRD (X-ray powder diffraction) to confirm their properties. In order to investigate the optimum conditions for Cd(II) adsorption, the amount of Cd(II) adsorbed by Zn-Al LDHs intercalated with EDTA (ZnAl-EDTA) under different conditions (i.e., adsorbent dosage, temperature and contact time) were determined by ICP-AES (inductively coupled plasma-atomic emission spectrometry). Adsorption isotherms of Cd(II) onto ZnAl-EDTA were measured at varying initial Cd concentrations (0.05 mg/L to 1 mg/L) under optimized conditions. The data were applied to Langmuir and Freundlich isotherms model, and well fitted by the Freundlich isotherms model. The pseudo-second-order kinetic model was more adequate to describe the kinetic in this case.

Layered Double Hydroxide Zn/M3+ (M3+= Al and Cr) as Highly Efficient Adsorbent of Heavy Metal Pb(II)

“…Pb 2+ removal with Ca-Al LDH can be removed at a high concentration of 6 ppm from an initial concentration of 10 ppm (Rojas, 2014). The work conducted by Asiabi et al (2017) with modified Ni-Cr/diphenylamine 4-sulfonate (DS) LDH to adsorp Pb with adsorpstion capacity reaching 309 mg/g at 293 K. Research by Zhang et al (2016) for Cd(II) with Zn-Al/EDTA LDH, the maximum adsorption capacity was 16.1 𝜇g 1−1/𝑛 •g −1 •L −1 according to the Freundlich equation, indicating that adsorption occurs in a multilayer. Adsorption capacity of Fe(II) metal up to 12.618 mg/g using Zn/Cr LDH with Freundlich equation was observed by Oktriyanti et al (2020).…”