Insights into the coordination-driven role of boron in Fe-doped carbon nitride composites activation of peracetic acid to remove tetracycline: Function and contribution of boron

The coordination strategy of non-metallic atoms was recognized as a great potential for improving the catalytic performance and stability of metal catalysts, although it remained a daunting task. We described a rational design for the introduction of coordinated Boron (B) atoms in Fe-g-C3N4 herein. The resulting FeB5-g-C3N4/PAA system exhibited glorious catalytic activity, removing 96.5 % of tetracycline (TC) within 60 min, surpassing the performance of the Fe-g-C3N4/PAA system by a factor of 1.36. In addition, the system has good acid resistance (pH=3-9) and interference resistance (HCO3-, HPO42-, Cl- and HA), while reduced toxicity of TC and leaching of ferric ions. Notably, B broke the inert electronic structure of graphitic carbon nitride (g-C3N4) and enhanced the electron transfer potential of FeB5-g-C3N4. The coordinated B atoms also had a profound effect on the Fe sites, which not only increased the Fe(II) content but also strengthened the electron-loss potential and PAA adsorption affinity. It served as a TC adsorption site to enhance the adsorption of TC simultaneously. These contributions not only accelerated the regeneration of the Fe(II)/Fe(III) redox cycle but also led to the conversion of high-valent iron oxide species and R-O & sdot; into main active species, which played crucial roles in the removal of TC. In sum-mary, this study offered insight into the role and contribution of B on metal catalysts, and it has showcased the practical potential of the FeB5-g-C3N4/PAA process for wastewater treatment applications.