Synthesis and characterization of magnetic metal-organic framework (MOF) as a novel sorbent, and its optimization by experimental design methodology for determination of palladium in environmental samples

This paper describes the synthesis and application of novel magnetic metal-organic framework (MOF) [(Fe3O4–Pyridine)/Cu3(BTC)2] for preconcentration of Pd(II) and its determination by flame atomic absorption spectrometry (FAAS). A Box–Behnken design was used to find the optimum conditions for the preconcentration procedure through response surface methodology. Three variables including amount of magnetic MOF, extraction time, and pH of extraction were selected as factors for adsorption step, and in desorption step, four parameters including type, volume, and concentration of eluent, and desorption time were selected in the optimization study. These values were 30 mg, 6 min, 6.9, K2SO4+NaOH, 6 mL, 9.5 (w/v %)+0.01 mol L−1, 15.5 min, for amount of MOF, extraction time, pH of extraction, type, volume, and concentration of the eluent, and desorption time, respectively. The preconcentration factor (PF), relative standard deviation (RSD), limit of detection (LOD), and adsorption capacity of the method were found to be 208, 2.1%, 0.37 ng mL−1, and 105.1 mg g−1, respectively. It was found that the magnetic MOF has more capacity compared to Fe3O4–Py. Finally, the magnetic MOF was successfully applied for rapid extraction of trace amounts of Pd (II) ions in fish, sediment, soil, and water samples.