Zirconium‐based adsorbent based on hydrolysis‐resistant strategy and its adsorption performance for As( III ) and As(V)

Abstract In this study, a nano‐amorphous hydrated zirconia adsorbent (Zr‐NA‐3) was synthesized via a hydrolysis‐resistant sol–gel strategy and systematically evaluated for arsenic removal from water. The adsorbent achieved a high specific surface area of 224.39 , approximately twice that of materials prepared by direct hydrolysis. Characterization revealed a hierarchical micro‐mesoporous structure (0.2–30 nm) dominated by an amorphous zirconium oxide framework with abundant surface hydroxyl groups, which provided sufficient active sites for arsenic adsorption. Batch adsorption experiments demonstrated adsorption capacities of 136.5 for As(III) at pH 11 and 139.3 for As(V) at pH 3, respectively. Adsorption kinetics followed a pseudo‐second‐order model, and thermodynamic analysis indicated that the adsorption process was spontaneous and endothermic, while the desorption process exhibited the opposite trend, being spontaneous and exothermic. Isotherm analysis showed that As(III) adsorption was better described by the Freundlich model (heterogeneous adsorption), whereas As(V) conformed more closely to the Langmuir model (monolayer adsorption), reflecting distinct adsorption behaviours under optimal pH conditions. X‐ray photoelectron spectrometer (XPS) and Fourier transform infrared spectrometer (FTIR) characterizations confirmed that surface complexation (via ligand exchange with surface hydroxyl groups) and electrostatic interactions were the dominant adsorption mechanisms. Furthermore, after three adsorption–desorption cycles, removal efficiencies remained above 94% for As(III) and 93% for As(V), with regeneration efficiencies of 92%–97%, accompanied by negligible zirconium leaching. Overall, the hydrolysis‐resistant strategy endows Zr‐NA‐3 with superior structural properties and arsenic adsorption performance, making it a promising candidate for the remediation of arsenic‐contaminated water.