Core-shell structured magnetic γ-Fe₂O₃@Cu-La composite material for enhanced arsenic removal: Behavior and mechanism

Arsenic removal has attracted growing attention due to its high toxicity, mobility, and carcinogenicity. For efficient arsenic uptake, we successfully fabricated a magnetic γ-Fe₂O₃@Cu-La composite material (CLFO). The CLFO exhibited high arsenic adsorption capacity through the synergistic effect of its Cu-La composite oxide phase, while the γ-Fe₂O₃ component endowed it with superior magnetic separation functionality. The core-shell structured CLFO consisted of smaller nanoparticles of irregular sizes and shapes. Results from batch experiments demonstrated that the CLFO exhibited effective removal capacities for both As(V) (160.4 mg/g) and As(III) (113.5 mg/g), with an optimal adsorption pH range of 6.0-7.0. The spent CLFO was successfully regenerated and used for arsenic removal from real water samples. Both As(V) and As(III) were taken up through the creation of inner-sphere surface complexes resulting from replacing the surface hydroxyl groups. Overall, the CLFO appeared to be an excellent option for eliminating arsenic in engineering applications.