Customizable Three-Dimensional Printed Zerovalent Iron: An Efficient and Reusable Fenton-like Reagent for Florfenicol Degradation

Zerovalent iron (Fe⁰)-based Fenton-like technology has great potential for treating recalcitrant organic pollutants (ROPs) in wastewater. However, rapidly and precisely manufacturing Fe⁰-based materials with the desired geometries is challenging. Herein, novel three-dimensional printed Fe⁰ (3DP-Fe⁰) and bimetallic 3DP-Ni/Fe⁰ were customized by 3D printing for efficient Fenton-like degradation of florfenicol (FLO), a typical antibiotic in wastewater. 3DP-Ni/Fe⁰ with hydrogen peroxide (H₂O₂) exhibited superior reactivity toward FLO than 3DP-Fe⁰, generating hydroxyl radicals (·OH) and atomic hydrogen to achieve >90% dehalogenation and >70% total organic carbon removal within 10 min. The resulting degradation intermediates possessed lower antibacterial activity than FLO and did not cause resistance gene proliferation in activated sludge. The Fenton-like activity of 3DP-Ni/Fe⁰ was similar across different shapes but increased with increasing porosity and size. Compared with powdered Ni/Fe⁰, 3DP-Ni/Fe⁰ exhibited faster electron transfer during Fe(II)/Fe(III) cycling, which increased the utilization efficiency of dissolved Fe²⁺ and H₂O₂ for ·OH production. Moreover, 3DP-Ni/Fe⁰ could be reused >150 times, 5-fold more than powdered Ni/Fe⁰, owing to its lower metal ion release and Fe⁰ depletion. 3DP-Ni/Fe⁰ with H₂O₂ can also efficiently remove chemical oxygen demand from real wastewater and other ROPs (e.g., acetaminophen, carbamazepine, thiamphenicol, and tetrabromobisphenol A).