Photofenton degradation of levofloxacin wastewater by hybrid biochar under circumneutral conditions

ZHAO Xia; WANG Hong-tao; YU Xiao-hong; YAN Jing; YANG Ming-yi; WANG Li; YU Li

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China Environmental Science ›› 2026, Vol. 46 ›› Issue (1) : 389-398.

Emerging Contaminants

Photofenton degradation of levofloxacin wastewater by hybrid biochar under circumneutral conditions

ZHAO Xia¹, WANG Hong-tao¹, YU Xiao-hong¹, YAN Jing¹, YANG Ming-yi¹, WANG Li², YU Li¹

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Abstract

The zero-valent iron-activated persulfate (ZVI-PS) method was used for sludge dewatering. The dewatered sludge was then mixed with humic carbon (HC) and carbonized to successfully prepare a hybrid biochar catalyst. When applied to levofloxacin (LVFO)-containing wastewater treatment in a photofenton system, the catalyst exhibited excellent performance under circumneutral conditions. It effectively addressed the traditional Fenton system’s dependence on acidic environments, thereby significantly broadening the applicable pH range. This study systematically investigated the effects of catalyst dosage, H₂O₂ concentration, xenon lamp power, and pH on LVFO degradation efficiency. The results showed that under optimal conditions (catalyst dosage: 1g/L, H₂O₂ dosage: 0.6mL/L, xenon lamp power: 300W, pH 7), the LVFO degradation rate by the hybrid biochar reached 92.58%—far higher than the 55.86% achieved by humic carbon. This superior performance was primarily attributed to the abundant iron species on the hybrid biochar surface, which facilitate iron cycling and thus enhance catalytic activity. Active species quenching experiments revealed that the system degrades LVFO mainly through the non-radical pathway of singlet oxygen (¹O₂), which explained its excellent degradation capacity under circumneutral conditions. After five cycles of reuse, the catalyst’s iron leaching rate was below 0.56%, and it retained high catalytic efficiency. A potential LVFO degradation pathway was proposed based on three-dimensional fluorescence spectroscopy and intermediate product detection.

Key words

levofloxacin / hybrid biochar / photofenton system / non-radical pathway

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ZHAO Xia, WANG Hong-tao, YU Xiao-hong, YAN Jing, YANG Ming-yi, WANG Li, YU Li. Photofenton degradation of levofloxacin wastewater by hybrid biochar under circumneutral conditions[J]. China Environmental Science. 2026, 46(1): 389-398

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