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

Zerovalent iron (Fe)-based Fenton-like technology has great potential for treating recalcitrant organic pollutants (ROPs) in wastewater. However, rapidly and precisely manufacturing Fe-based materials with the desired geometries is challenging. Herein, novel three-dimensional printed Fe (3DP-Fe) and bimetallic 3DP-Ni/Fe were customized by 3D printing for efficient Fenton-like degradation of florfenicol (FLO), a typical antibiotic in wastewater. 3DP-Ni/Fe with hydrogen peroxide (HO) exhibited superior reactivity toward FLO than 3DP-Fe, 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/Fe was similar across different shapes but increased with increasing porosity and size. Compared with powdered Ni/Fe, 3DP-Ni/Fe exhibited faster electron transfer during Fe(II)/Fe(III) cycling, which increased the utilization efficiency of dissolved Fe and HO for ·OH production. Moreover, 3DP-Ni/Fe could be reused >150 times, 5-fold more than powdered Ni/Fe, owing to its lower metal ion release and Fe depletion. 3DP-Ni/Fe with HO can also efficiently remove chemical oxygen demand from real wastewater and other ROPs (e.g., acetaminophen, carbamazepine, thiamphenicol, and tetrabromobisphenol A).