Tetracycline (TC), a commonly used antibiotic, poses serious environmental and health problems, even if present in trace amounts in the aqueous systems, including rivers and groundwater. This study introduces the catalytic wet air oxidation (cWAO) technique as an efficient technique for treating TC-laden water, using the pelletized biochar-supported Cu nanoparticle (NP)-tipped graphitic carbon nanofibers (CNFs) as a catalyst. The proposed materials configuration integrates the favourable redox potential and multiple oxidation states of Cu NPs with high electron conductivity of CNFs. Micron-sized biochar is derived by pyrolysis of the naturally resourced bamboo (Bambusa vulgaris) shoots, and serves as a stabilizing matrix for Cu NPs without leaching. Physicochemical characterization reveals the formation of a meso-macroporous structure with the Cu loading of ~10.8 mg/g and abundance of oxygen functional groups. The cWAO activity tests confirm ~99% removal of aqueous TC using 1 g L-1 dose of the pelletized catalyst at 100 °C and 2 bar, with the simultaneous reduction of chemical oxygen demand (~78%) and total organic carbon (~80%). The radical scavenging test and electron paramagnetic resonance analysis confirm the degradation of TC via the radical (•OH and •O2⁻) and non-radical (1O2) pathways. Liquid chromatography-mass spectroscopy analysis confirms the transformation of the TC molecule to reaction intermediates, eventually break-down to CO2 and H2O. The reusability test shows the stability of the catalyst over five oxidation cycles, while the toxicity test confirms the treated cWAO samples to be harmless. The findings clearly underscore the need for further study on the Cu-CNF/biochar pellets for treating the recalcitrant pharmaceutical compounds-laden wastewater by cWAO in a packed bed reactor under flow conditions.

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