Adsorption of Metanil Yellow Azoic Dye from Aqueous Solution onto Mg‐Fe‐NO₃ Layered Double Hydroxide

We report the preparation and characterization of a layered double hydroxide (LDH) adsorbent for azoic dye, metanil yellow (yellow GX; YGX) removal. The nanoparticles of Mg‐Fe‐LDH‐NO 3 adsorbent were prepared with Mg/Fe molar ratio of 3:1 by a hydrothermal process and coprecipitation method at pH 9.5 and were characterized by X‐ray powder diffraction (XRPD), thermal gravimetric analysis (TGA), elemental analysis, and Fourier transform infrared spectroscopy (FT‐IR). The size and morphology of nanoparticles were examined by scanning electron microscopy (SEM). The XRD patterns indicate that the intercalation of YGX between the LDH layers has not occurred and surface adsorption has happened. In the adsorption experiments, the Gibbs free energy Δ G 0 values, the enthalpy Δ H 0 , and entropy Δ S 0 was determined. The isotherms showed that the adsorption of YGX by Mg‐Fe‐LDH‐NO 3 was both consistent with Langmuir and Freundlich equations.