Cyanide is a highly toxic anion, which is found normally in the wastewater of numerous industries, such as electroplating, case-hardening of metals, extraction of gold, coal gasification, and production of organic chemicals. The release of cyanide into the environment can cause adverse chronic and acute toxic effects on several organs of the human body. Cyanide can be removed from aqueous solutions using different but expensive methods. In this study, Mg/Al layered double hydroxide (Mg/Al-LDH) containing biodegradable amino acid derivative, as an adsorbent was used to remove cyanide. Mg/Al-LDH was characterized by X-ray diffraction (XRD), Fourier Transmission Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), and Transmission Electron Microscopy (TEM). Adsorption experiments were carried out in batch mode as a function of initial cyanide concentration, contact time, pH, temperature and competitive adsorption to get optimum adsorption capacity. The results showed that at the adsorbent dose of 0.0500 g, contact time of 30 min, pH of 11.0, temperature of 298 K and cyanide concentration of 100.0 mg/L, the cyanide adsorption capacity reached 71.4 ± 2.8 mg/g. The adsorption kinetic study showed that the adsorption process followed well with pseudo-second-order model. Furthermore, the adsorption isotherm data were also fitted well with Langmuir isotherm. The practical ability of the prepared adsorbent for removal of cyanide from industrial samples was evaluated using silver polishing industrial effluents. The obtained results showed that Mg/Al-LDH can be used for removal of cyanide ion from industrial effluents.
