N-enriched covalent organic polymer derived nanoscale zero-valent iron for effective oxidative degradation of tetracycline

Considering the agglomeration and instability of nanoscale zero-valent iron (NZVI, Fe⁰), N-enriched covalent organic polymer derived zero-valent iron (NZVI@N-COP) composite with excellent activity, high stability and as well as effective antibiotic removal capacity was innovatively synthesized via solvent thermal and in-situ reduction growth methods. The dispersion of NZVI is distinctly improved by using N-enriched covalent organic polymer (N-COP) as both matrix and dispersant. NZVI@N-COP exhibited excellent electron transfer capability and high TC removal efficiency without additional oxidants. The removal efficiency of TC was increased by 42.4% compared with that of pristine NZVI. The promoted activity of NZVI@N-COP can be ascribed to the strong coordination of Fe with N atoms between NZVI and N-COP, which reduces oxidation and leakage of Fe, exposing more available reactive sites to produce reactive oxygen species. Additionally, Characterization results show that the reaction mechanism involves adsorption and chemical oxidation of O₂•– without additional oxidants. Optimum operating conditions were determined to be NZVI@N-COP dosage 0.1 g·L⁻¹, pH 6, and temperature 298 K. This research put forward a simple method for synthesis of highly effective N-COP derived NZVI and its application in the treatment of antibiotic pollutants.