Effective adsorption of methyl orange dye from water samples over copper(II) Schiff-base complex-immobilized cerium-based metal-organic framework

Abstract

Herein, a copper(II) Schiff-base complex derived from the condensation of salicylaldehyde (Sal) with amino groups of a cerium-based metal-organic framework of type, UiO-66-NH2(Ce), denoted here Cu(II)/Sal@UiO-66(Ce), has been prepared and characterized by EDX, SEM, FT-IR, BET and XRD, as well as thermal gravimetric analysis (TGA) techniques. The nominal nanostructure including dual-metal sites (Ce and Cu) was considered as a novel adsorbent for removing methyl orange (MO, as an organic contaminant) dye from aqueous media. Accordingly, various key experimental factors such as the pH, mass of adsorbent, contact time, and eluent type were tested and optimized. Based on experimental outcomes, the adsorption of MO for Cu(II)/Sal@UiO-66(Ce) reaches a maximum of 98.8 % efficiency at a pH of 6 and a maximum extraction capacity of 454.5 mg/g. Also, the limit of detection (LOD) and relative standard deviation (RSD%) were 0.63 μg/L and 2.4 %, respectively, under the optimum condition. Reusability, short adsorption time, and low-cost cerium-based MOF are the other advantages of the corresponding adsorbent. In addition, the porous adsorbent was applicable for the MO adsorption from environmental water samples.