New insights into residual triiodide ion removal from iodinated water using magnetic CoFeO nanoparticles: exploring adsorption behavior and mechanisms.

This study evaluates the adsorption performance of cobalt ferrite (CoFeO)-based magnetic nanoadsorbents (CF-MagNa) for the removal of triiodide ions ( ) from iodinated water. The crystalline structure and phase purity of the synthesized material were confirmed via X-ray diffraction (XRD), which determined a crystallite size of 42 nm and a specific surface area of 26.98 m/g. Field emission scanning electron microscopy (FESEM) revealed a porous morphology conducive to enhanced adsorption. The ferromagnetic properties of CF-MagNa were characterized using vibrating sample magnetometry (VSM), which demonstrated a saturation magnetization (σ) of 74.98 emu/g, a remanent magnetization (σ) of 29.82 emu/g, and a coercivity (H) of 1304 Oe, significant magnetic separation potential. Batch adsorption experiments revealed a 61.6% reduction in concentration at a CF-MagNa dosage of 2 mg/mL. Adsorption isotherms were analyzed, with the Langmuir model yielding a maximum adsorption capacity (Q) of 13.641 mg/g and a Langmuir constant (K) of 0.00996 L/mg. The Freundlich model provided a capacity factor (K) of 1.892 mg/g and a heterogeneity factor (n) of 1.805 L/mg, while the Temkin model yielded a heat of adsorption (B) of 3.404 J/mol and a Temkin constant (K) of 0.743 L/g. The Dubinin-Radushkevich (D-R) isotherm demonstrated the highest correlation (R = 0.97), with a maximum adsorption capacity of 8.28 mg/g. These results highlight CF-MagNa's efficacy as a potential adsorbent for water treatment, with promising applications in environmental remediation and sustainable water purification technologies.