MCM-41@Cu–Fe–LDH magnetic nanoparticles modified with cationic surfactant for removal of Alizarin Yellow from water samples and its determination with HPLC

An adsorbent formed from MCM-41 and layered double hydroxides (LDH) coated on magnetic nanoparticles was synthesized and modified with a cationic surfactant (Fe3O4@MCM@Cu–Fe–LDH) for use in dispersive micro solid-phase extraction for removal of Alizarin Yellow (AY) (an anionic dye) prior to high-performance liquid chromatography–ultraviolet (HPLC–UV) detection. This adsorbent was obtained from mesopore MCM-41 coated with Fe3O4 as main core and Cu–Fe–layered double hydroxide (Cu–Fe–LDH) as nanoplatelet shell. The adsorbent was characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. Also, the surface morphology, Brunauer–Emmett–Teller (BET) specific surface area, and Barrett–Joyner–Halenda (BJH) pore size of the adsorbent were obtained. The adsorption isotherms were studied based on the Langmuir and Freundlich models. Adsorption data were successfully fit using the Langmuir model, showing maximum adsorption capacity of 121.95 mg g−1. The proposed method showed good linearity for AY with correlation coefficient R2 > 0.9998. The limit of detection was 0.5 µg L−1. Precision of 6.5% was obtained, as relative standard deviation (RSD) (n = 6). The method was successfully applied to determine AY in well and wastewater samples.