Triple-action amyloid lysozyme-coated magnetic nanospheres for highly efficient reduction and removal of Cr( vi ) from environmental water

Hexavalent chromium (Cr(VI)) is a potent carcinogen and environmental contaminant that poses serious health risks to humans. Its widespread presence in aquatic systems has raised significant global concern. In this work, a highly effective magnetic nanoadsorbent (Fe₃O₄@PTL) is fabricated using Fe₃O₄ as the carrier and phase-transitioned lysozyme (PTL) as the functional coating for the efficient removal of Cr(VI) through an innovative triple-effect remediation strategy. Electrostatic interactions promote the adsorption of Cr(VI) by driving its movement toward the positively charged surface of Fe₃O₄@PTL. The electron-rich PTL layer synergizes with Fe(II) to efficiently reduce toxic Cr(VI) to the less hazardous Cr(III), attaining an exceptional reduction efficiency of 82.98%. Subsequently, the PTL coating significantly enhances Cr(III) immobilization capacity (72.36%) through multifunctional group complexation. Moreover, the iron leaching of the PTL-encapsulation material was reduced by approximately 80% compared to that of unencapsulated Fe₃O₄, demonstrating excellent acid resistance. As a result, the synthesized nanoadsorbent exhibits strong reducibility, high removal efficiency, and minimal iron leaching, significantly enhancing its practical applicability. Hence, this work not only provides an effective solution for controlling Cr(VI) pollution but also unveils an advanced triple-action strategy to guide the future development of high-performance heavy metal adsorbents.