Design and fabrication of recoverable Fe-biochar composite synthesized through CN- sequestration from wastewater for enhanced Peroxy-bond activation

초록

Easy transformation of wastewater treatment residue into a functional catalyst is a promising yet a challenging endeavor that inspire researchers worldwide. Herein, a rational fabrication strategy was established to synthesize rice-husk biochar supported Fe3O4 magnetic composite (RHFex) from a solid residue generated during treatment of real CN- contaminated wastewater. The resulting RHFex composite achieves 100 % of tetracycline removal in 120 min through a Fenton-like reaction. Surface characterization reveals that a porous Fe3O4 structure that anchored on rice husk is the active component responsible for SO4 center dot- and (OH)-O-center dot radical generation. Among the tested transition metal (Fe2+, Co2+, Ni2+, Mn2+) ions, only Fe2+ and Co2+ demonstrated best CN- removal efficiency by bringing CN- concentration from 1100 mu g L-1 to <200 mu g L-1 level. Building on this, the upcycling strategy was further extended to Co2+, enabling the successful synthesis of zerovalent Co-0 anchored rice husk composite (RHCox) using the same approach. Degradation studies of various antibiotics with RHFex and RHCox revealed TC removal is faster in both PS and PMS oxidants, while other antibiotics degrade quickly only with PMS. This innovative upcycling strategy showcases waste-derived catalyst design that promotes circular economy practices in managing CN- contaminated wastewater treatment and associated solid residues.

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