E‐Waste Derived Magnetic Nanoadsorbents for Sustainable Water Purification
Qaisar Maqbool, Hamilton Uchenna Aharanwa, Susanne Gross, Tagir Shamardanov, Michael Stöger‐Pollach, Günther RupprechterABSTRACT
The transition to a circular economy requires scalable routes for upcycling hazardous waste into high‐value functional materials. Here, we report a synthesis of magnetic zinc ferrite/maghemite‐based nanoadsorbents utilizing precursors recovered entirely from spent batteries and oxidized iron scrap. Energy Loss Magnetic Chiral Dichroism (EMCD) measurements under matched experimental conditions revealed about 18% stronger EMCD response for ZnF‐Ni than for unmodified ZnFe 2 O 4 . In addition, ZnF‐Ni enabled substantially faster overall treatment through the combined adsorption and magnetic separation procedure, reducing the processing time to approximately 10–15 min compared with approximately 24 h for ZnF. Magnetic separation facilitates a pH‐switchable process where dyes are removed via protonated surface hydroxyls and subsequently released in alkaline media. We successfully validated a continuous, flow‐through remediation prototype that instantaneously traps the dye‐nanoabsorbent in situ by an external magnetic field from a moving suspension stream, followed by dye release and material recovery. This study presents a techno‐economically practical pathway for e‐waste utilization, showing reaction‐based theoretical atom economy of ∼77% for spinel ferrite formation.