Co-Fe-layered double hydroxide decorated amino-functionalized zirconium terephthalate metal-organic framework for removal of organic dyes from water samples.

In this study, a new efficient adsorbent of Co-Fe-layered double hydroxides@metal-organic framework (Co-Fe-LDH@UiO-66-NH) was synthesized and used for extraction of methylene blue (MB) and methylene red (MR) from water samples prior to their determination by UV-Vis spectrophotometer. The adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), X-ray Diffraction (XRD), and Brunauer-Emmett-Teller (BET) analyses. The impact of various parameters such as pH of the aqueous phase, extraction time, amount of adsorbent, type and volume of eluent solvent, desorption time, and sample volume were studied. The maximum extraction recovery was obtained at an optimized pH 8.0 and extraction time 10.0 min. The adsorption process was fitted by the Langmuir model with a maximum adsorption capacity of 555.62 mg/g and 588.2 mg/g, respectively, for MB and MR. Under optimum conditions, the limit of detection (LOD) for MB was 0.7 μgL and 0.9 μgL for MR. Furthermore, the Co-Fe-LDH@UiO-66-NH composite showed high efficiency for the removal of the analytes from environmental water samples.