LAUSR

Abstract A novel Fe/La oxide magnetic microspheres for enhanced As(V) removal from diluted wastewater was synthesized and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectrometer, and vibrating sample magnetometer. The prepared Fe/La oxide magnetic microspheres possessed satisfactory pore size distribution with stable spheres structure. Adsorption of arsenate onto Fe/La OMMs was first investigated using batch experiments for the determination of pH edge, adsorption kinetics, and isotherm. The removal of As(V) by Fe/La oxide magnetic microspheres could reach almost 100 % under As(V) solution of 1 mg/L at the optimum adsorbent dosage of 0.1 g/L. The adsorption kinetics followed an intraparticle diffusion model, and the adsorption isotherm was well described by the Langmuir model with the maximum adsorption capacity of 62.32 mg/g for As(V) at pH 4. Besides, the Fe/La oxide magnetic microspheres performed well in selectivity and magnetic separation. PHREEQC programming suggested the adsorption process could be better described by the surface complexation model and reinforced the understanding of the Fe/La oxide magnetic microspheres in true wastewater treatment applications. The adsorption mechanism is attributed to surface complexation and intraparticle diffusion, including electrostatic interaction, ligand exchange, and complex formation. The developed Fe/La oxide magnetic microspheres showed great potential in the advanced As(V) processing for the dilute natural arsenic-contaminated water.