Environmentally benign Fe-Zr bimetallic adsorbent for efficient removal of arsenic from water

Arsenic contamination of drinking water continues to be a major global environmental and public health problem. Herein, a Fe-Zr bimetallic functional polymer architecture (qFZV) was synthesized by the free-radical copolymerization and quaternization process, and was used for arsenic removal. The successful incorporation of Fe and Zr species, quaternary ammonium (-N⁺R 3 Cl⁻) functionalities, and a porous heterostructure morphology favourable for adsorption was confirmed by instrumental techniques such as XRD, FTIR, FESEM, and XPS. The batch experiments showed the rapid adsorption kinetics and high affinity for both As(V) and As(III) and the equilibrium was achieved in short time. The adsorption data were fitted well to Langmuir isotherm model indicating monolayer adsorption on a homogeneous active site. The qFZV adsorbent demonstrated maximum adsorption capacities of 33.77 mg g −1 for As(V) and 29.57 mg g −1 for As(III) with strong tolerance to coexisting ions. XPS analysis of the As 3d region showed peaks at 45.16 and 42.65 eV confirming the adsorption of As(V) and As(III) respectively. The improved performance can be attributed to the synergistic effect of ligand exchange and electrostatic interactions from the Fe-Zr active centres, quaternary ammonium groups and interconnected porous channels. Moreover, qFZV exhibited excellent adsorption efficiency for multiple regeneration cycles, proving its stability and reusability. These findings suggest that qFZV can be a potent and regenerative, sustainable adsorbent for the remediation of arsenic-contaminated water.