Magnetic polyelectrolyte complex (PEC)-stabilized Fe/Pd bimetallic particles for removal of organic pollutants in aqueous solution

Abstract

Magnetic polyelectrolyte complex (PEC) based on chitosan and sodium ligninsulfonate as the support to stabilize Fe/Pd bimetallic particles (mPEC-Fe/Pd) were synthesized for the degradation and decolorization of organic pollutants in aqueous solution. The morphologies and structures of the as-obtained composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). Various factors potentially influencing the decolorization performance of methyl blue (MB) and malachite green (MG) from aqueous solution (i.e., mPEC-Fe/Pd dosage, solution pH, initial dye concentration and reaction temperature) were investigated. mPEC-Fe/Pd exhibited higher catalytic activity towards the removal of MB and MG, which involved both adsorption of dye molecules on mPEC surface and reduction reaction by Fe/Pd particles. Nearly 99% and 91% of MB and MG were removed at initial dye concentration of 100 mg l−1 with 1.0 g l−1 of mPEC-Fe/Pd, respectively. The decolorization efficiency of MB and MG increased with the increase of solution pH and mPEC-Fe/Pd dosage but decreased with the increase of initial dye concentrations. mPEC-Fe/Pd could be recycled effectively, and the removal percentage of MB reached as high as 83.5% even at the eighth reuse. Furthermore, the catalytic performances were further investigated to remove other organic pollutants, in which 92.4% of oxytetracycline, 85.1% of Tetrabromobisphenol A, and 34.7% of norfloxacin were removed at 50 mg l−1 of aqueous solution using 1.0 g l−1 of mPEC-Fe/Pd. Due to high removal efficiency, rapid reaction rate, easy separation and good reusability, mPEC-Fe/Pd had the potential to become an environmental remediation material for the treatment of wastewater containing organic compounds.