Novel phase-controlled Al_2.66O_3.99/iron oxide nanocomposites for rapid Cu(II) removal from acidic water

In this study, alumina/iron oxide nanocomposites are synthesized via a simple, cost-effective co-precipitation method and investigated for the removal of copper ions from acidic aqueous media. Five samples with varying iron oxide phase contents are prepared by varying the precursor molar ratios. Structural analysis confirms the coexistence of Al₂.₆₆O₃.₉₉ and iron oxide phases, while Rietveld refinement reveals that the iron oxide phase fraction increases from 0.2% to 67.2% across the synthesized samples. The nanocomposites are characterized in detail using a range of analytical methods, including structural, morphological, optical, magnetic, and elemental analyses. Magnetic measurements indicate soft-magnetic behavior, with an enhanced response observed in the sample with the highest iron oxide content. The experimental results demonstrate rapid uptake of Cu(II), with significant removal occurring within the first few minutes and removal efficiencies exceeding 90% after 90 min for most samples. Nonlinear kinetic analysis indicates that the pseudo-second-order model provides a good description of Cu(II) adsorption behavior, while complementary characterization elucidates the underlying adsorption interactions. Owing to their tunable phase composition and effective Cu(II) adsorption performance, these alumina/iron oxide nanocomposites show potential for wastewater treatment in mildly acidic aqueous media.Clinical trial number: Not Applicable.