Efficient Removal of Trace as (Iii) by a La/Fe Composite Membrane Filter: The Composite Form of La, the Dynamic Adsorption and Adaptability

In this study, three nanocomposite adsorbents (La(OH)3-Fe3O4, La2O3-Fe3O4, LaxFe3-xO4) based on Fe3O4 and different forms of lanthanum were prepared for As(III) removal to investigate the optimal form of Fe3O4-lanthanum composites. As a result, La0.15Fe2.85O4 had the highest adsorption capacity, more stable structure, and high regeneration ability. The kinetic and isotherm models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating the chemisorption mechanism. Furthermore, the adsorption mechanism was analyzed by X-ray photoelectron spectroscopy (XPS), which showed that electrostatic attraction and surface complexation were the main driving forces of As(III) removal. In order to enhance the practical application of nano-adsorbent, a composite nanofiber membrane (La0.15Fe2.85O4/PAN) was prepared by embedding La0.15Fe2.85O4 in polyacrylonitrile, and the arsenic removal efficiency of the membrane was further investigated by static and dynamic adsorption through building a membrane filter, respectively. The results showed that the membrane reactor had good processing capacity, anti-interference ability and reusability. This study confirmed the most favorable form of la-Fe composite, and provided a composite membrane technology to realize its practical application for water treatment.