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• A high performance nZVI encapsulated with Bi(0) in biochar was synthesized. • nZVI@Bi0/PPBC showed high catalytic performance to activate PDS for degradation ACE. • Bi(I/II) accelerated the cycle of Fe(II) and Fe(III). • O 2 ·−, 1O 2 and electron transfer played major in nZVI@Bi0/PPBC/PDS system. • The introduction of Bi increased the repeatability and stability of nZVI. Due to the contradiction between superior reaction kinetics and imperfect reproducibility of nanoscale zero-valent iron (nZVI) in persulfate oxidation systems, how to improve the reusability of nZVI while highly guaranteeing efficiency is an important but challenging matter. Hence, we took a hydrothermal-assisted carbon reduction to synthesize nZVI encapsulated with Bi being loaded on pomelo peel biochar (nZVI@Bi0/PPBC), and the results indicated that the presence of Bi could improve the reproducibility of nZVI and facilitate the removal of acetaminophen (ACE) in the persulfate (PDS) system. The degradation rate constant of the nZVI@Bi0/PPBC 800 composite for ACE was approximately 1.5 times higher than that of the nZVI/PPBC 800. nZVI exhibited synergistic effects with Bi on PDS activation through electron transfer. Interestingly, the Bi(0) became increasingly pure as the pyrolysis temperature increased, and the catalytic performance of ZVI@Bi0/PPBC became better. In addition, electron spin resonance and quenching experiments revealed that 1O 2 and O 2 · − were the predominant reactive oxygen species in nZVI@Bi0/PPBC/PDS system. The nZVI@Bi0/PPBC/PDS system showed excellent oxidation ability across a broad pH range (3.0–9.0) and resisted interference from certain anions. This work reveals the possible role of Bi(0) in nZVI based PDS system, and provides an idea for the protection of nZVI. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green and facile α-FeOOH/GBC Fenton-like systems were constructed to remove OTC. • The performance of α-FeOOH/GBC enhanced with the increase of GBC's graphitization. • The major role of GBC was to facilitate the reaction between H 2 O 2 and Fe(III). • Donated eletrons for fasting Fe(III)/Fe(II) redox cycle was another role of GBC. • O 2 - and 1O 2 were identified as the predominant ROS for OTC degradation. Due to the contradiction between attractive properties and undesirable Fenton-like catalytic performance of iron minerals, how to enhance their Fenton-like catalytic activity is a critical but challenging issue. Here, we took an eco-friendly approach to improve the Fenton-like catalytic capacity of goethite (α-FeOOH) by loading it on graphitized biochar (GBC), and the results indicated that the existence of GBC could successfully facilitate the oxytetracycline (OTC) removal. The degradation rate constant of α-FeOOH/GBC-10 composite was approximately 2.1 times higher than that of α-FeOOH. GBCs with different graphitization degrees were obtained by adjusting the pyrolysis temperature. Interestingly, the improvement of catalytic activity of α-FeOOH/GBC was well correlated with the graphitization degree of GBC, and the graphitized structures (sp2-C) and functional group (C O) in GBC could expedite the blocked Fe(III)/Fe(II) cycling by speeding up the electrons transfer from H 2 O 2 to α-FeOOH and donating electrons to Fe(III). In addition, the electron spin resonance and quenching experiments demonstrated that OTC removal was attributed to the joint action of •OH, O 2 −, and 1O 2. This study sheds light on the possible role of GBC in Fenton-like reactions based on iron minerals and thus, lays the groundwork for the rational construction of more efficient Fenton-like catalytic systems. [ABSTRACT FROM AUTHOR]