In this study, nano zero-valent iron (nZVI) was loaded onto walnut shell activated carbon by liquid phase reduction method to synthesize nanocomposites (WS-AC/nZVI), which was used as a catalyst to activate PMS to efficiently degrade tetracycline in solution. The results showed that under the conditions of TC concentration of 100 ppm, PMS dosage of 0.2 mM, and WS-AC/ nZVI dosage of 0.1 g/L, the TC removal rate could reach 81 %. Based on quenching experiments and electron spin resonance (EPR), it was verified that the •OH, SO₄^•− and ¹O₂ bound on the catalyst surface were the main reactive oxygen species during the reaction. The intermediates of TC were identified by UPLC-MS and DFT, and the possible degradation pathway of TC was deduced. The degradation mechanism of TC was comprehensively evaluated by Fukui function, ALIE and three-dimensional ESP analysis. The catalyst still maintained a high TC removal efficiency after four cycles of experiments, and the minimal iron loss on the surface of the catalyst indicated its good stability. The efficient and stable WS-AC/nZVI activated PMS showed great potential for degradation of antibiotics.
 

Nano zero-valent iron (nZVI); Tetracycline (TC); Potassium persulfate (PMS); Activation; Recyclability.