Mechanochemical synthesis of microscale zero-valent iron/N-doped graphene-like biochar composite for degradation of tetracycline via molecular O2 activation

In this study, we prepared a micron zero-valent iron/ N -doped graphene-like biochar (mZVI/NGB) composite using a mechanochemical method for tetracycline (TC) degradation through O 2 activation. The mZVI and NGB components formed a strong coupling catalytic system, with mZVI acting as an electron pool and NGB as a catalyst for H 2 O 2 generation. Under circumneutral pH (5.0–6.8), the mZVI/NGB composite exhibited exceptional TC removal efficiency, reaching nearly 100 % under optimal conditions. It also showed good tolerance to co-existing anions, such as Cl - , SO 4 2- , and humic acid. Further studies found that the TC degradation mechanism was mainly ascribed to the non-radical pathway ( 1 O 2 and electron transfer), and the Fe 2+ /Fe 3+ redox cycle on the composite's surface also played a crucial role in maintaining catalytic activity. This research contributes to the development of advanced materials for sustainable and effective water treatment, addressing pharmaceutical pollutant contamination in water sources.