Antibiotics are frequently detected in the aquatic environment but are difficult to remove. In this study, tetracycline, a typical representative of antibiotics, was screened as a natural iron ore, limonite, as a fluidized bed stretcher to investigate the efficacy of its catalytic hydrogen peroxide (H2O2) for the degradation of tetracycline, and the effects of the reaction time, the reaction pH, the stretcher dosage, the tetracycline The effects of reaction time, reaction pH, stretcher dosage, initial concentration of tetracycline solution, H2O2 dosage, number of dosages and stretcher expansion on the degradation of tetracycline in the limonite/Fenton fluidized bed system were investigated, and the repeatability of the stretcher was also studied. The results showed that the removal rate of tetracycline could reach about 90% when the reaction pH, stretcher dosage, initial concentration of tetracycline solution, H2O2 dosage, number of dosages, and stretcher expansion rate were 3, 30 g/L, 40 mg/L, 0.6 mmol/L, 1 time, and 100%, respectively. The removal rate remained around 50% after six batches when in the multi-batch influent experiment. Through SEM, XRD, XPS and EPR characterization of limonite, the rough surface was found by SEM, and the main crystalline phase on the surface was hydroxyl iron oxide analyzed by XRD, and a decrease in the proportion of divalent iron and an increase in the number of organic functional group species on the surface of the stretcher were detected by XPS, and the reactive oxygen species playing a major role in the system was identified as •OH by EPR, and the heterogeneous Fenton reaction was assumed to have taken place. reaction was identified as •OH, and it was hypothesized that heterophasic Fenton reaction occurred to degrade the tetracycline.

Jingjing Zhou, Yinlong Zhang, Rong Nie. Use of limonite as a Fenton fluidized bed stretcher to treat tetracycline wastewater with over 90% removal rate. Nature Environmental Protection (2025), Vol. 6, Issue 1: 24-35. https://doi.org/10.38007/NEP.2025.060103.

[1] Song L, Li L, Yang S, et al. Sulfamethoxazole, tetracycline and oxytetracycline and related antibiotic resistance genes in a large-scale landfill, China[J]. Science of the Total Environment, 2016, 551: 9-15.

[2] Chen C Q, Zheng L, Zhou J L, et al. Persistence and risk of antibiotic residues and antibiotic resistance genes in major mariculture sites in Southeast China[J]. Science of the Total Environment, 2017, 580: 1175-1184.

[3] Liu X, Zhang H, Li L, et al. Levels, distributions and sources of veterinary antibiotics in the sediments of the Bohai Sea in China and surrounding estuaries[J]. Marine Pollution Bulletin, 2016, 109(1): 597-602.

[4] Wang Z, Chen Q, Zhang J, et al. Characterization and source identification of tetracycline antibiotics in the drinking water sources of the lower Yangtze River[J]. Journal of environmental management, 2019, 244: 13-22.

[5] Daghrir R, Drogui P. Tetracycline antibiotics in the environment: a review[J]. Environmental chemistry letters, 2013, 11: 209-227.

[6] Liu H, Yang Y, Sun H, et al. Effect of tetracycline on microbial community structure associated with enhanced biological N&P removal in sequencing batch reactor[J]. Bioresource technology, 2018, 256: 414-420.

[7] Zhang Wen bo,HE Dandan,WANG Jiuling,ZHANG Yupeng,CHU Ling,ZHANG Hong. Adsorption of tetracycline by chitosan/magnetic iron bumpstone[J]. Industrial Water Treatment,2023,43(07):128-134.

[8] LIU Jialu,ZHU Yu,LIU Zhaoyu,HU Boeyin,XIAO Zhaibing.Application of PDS/CoFe2O4 activation system in tetracycline wastewater treatment[J]. Industrial Water Treatment,2023,43(04):139-143.

[9] ZHANG Xiao,ZHANG Jing,YAN Chunhui,HUANG Xue,WU Qingping.CuO@C-catalyzed degradation of tetracycline hydrochloride by peroxodisulfate[J]. Water Treatment Technology,2019,45(04):17-20+26.

[10] Oberoi A S, Jia Y, Zhang H, et al. Insights into the fate and removal of antibiotics in engineered biological treatment systems: a critical review[J]. Environmental science & technology, 2019, 53(13): 7234-7264.

[11] Cai Q Q, Lee B C Y, Ong S L, et al. Fluidized-bed Fenton technologies for recalcitrant industrial wastewater treatment–Recent advances, challenges and perspective[J]. Water Research, 2021, 190: 116692.