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.