Fe(III) Complexed Polydopamine Modified Mg/Al Layered Double Hydroxide Enhances the Removal of Cr(VI) from Aqueous Solutions

Herein, we report the preparation of Fe(III) complexed polydopamine modified Mg/Al layered double hydroxides composite material (LDHs@PDA-Fe(III)) and its application to the removal of Cr(VI) in aqueous solution. LDHs@PDA-Fe(III) was characterized and analyzed by field-emission scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transformed infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron (XPS). The adsorption performance was studied through a series of adsorption experiments. Investigate the effects of pH, time, temperature, concentration and other factors. When C-0 = 800 mg/L, T = 308 k and pH 3, the maximum adsorption capacity obtained in the experiment was 683.4 mg/g. In addition, after 5 adsorption cycles, LDHs@PDA-Fe(III) still shows excellent adsorption capacity and stability. Combining adsorption experiments and characterization analysis, it is inferred that the adsorption of Cr(VI) by LDHs@PDA-Fe(III) is the result of the synergistic effect of multiple adsorption mechanisms. Therefore, the efficient removal capacity and excellent stability make LDHs@PDA-Fe(III) an ideal adsorbent for removing Cr(VI) from aqueous solutions.