Synergy between graphitized biochar and goethite driving efficient H2O2 activation: Enhanced performance and mechanism analysis.

[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]