Due to the persistence in residue and the emission to environment, antibiotics have become the emerging contaminants. Tetracyclines, as the largest amount of antibiotics in the breeding industry, were investigated in this study. For eliminating the tetracyclines, anaerobic culture was enriched from livestock waste after four generations and FeOn(OH)m modified oyster shell powders (OSPs) were amended into the enrichment culture as auxiliary method. Tetracycline and oxytetracycline were selected as the model compounds. The adsorption models (Langmuir and Freundlich isotherms) of tetracycline and microbes on OSPs were simulated respectively. With the addition of FeOn(OH)m modified OSPs, the transformation efficiency of oxytetracycline achieved 81.5% after 22 days’ incubation, approximately 1.85 times higher than the 4th generation (G-IV) enrichment culture without modified OSPs. Dehydration, demethylation, dehydroxylation and decarboxylation took place under anaerobic condition, inferred from the detected metabolites transformed from oxytetracycline. Genus Methanosarcina and two operational taxonomic units (OTUs) assigned to order Clostridiales , showed an increasing trend on abundance, indicating the contribution to transformation of oxytetracycline. Therefore, the FeOn(OH)m modified OSPs and enrichment culture can accelerate the transformation of oxytetracycline simultaneously, indicating a promising utilization not only for waste water system but also for antibiotic contaminated biomass treatment.
Xueqian Yan,Jin Qian,Xiangjun Pei,Lihong Zhou,Rui Ma,Mingkuan Zhang,Yufei Du,Linqin Bai
In this study, a magnetic NiFe 2 O 4 /MWCNTs/BiOI composite were fabricated and applied for enhanced and sustainable photocatalytic degradation of doxycycline (DOX) under UV light irradiation. The as-synthesized material was characterized by a series of techniques and its photocatalytic property was assessed via a couple of batch tests. With the pH at 3.0 and NiFe 2 O 4 /MWCNTs/BiOI loading of 1.5 g L −1 , the DOX degradation (at 45 mg L −1 ) efficiency could achieve 92.18% with the reaction rate constant k of 0.0072 min −1 . The high mineralization of DOX suggests the strong oxidation of both the parent pollutant and the intermediary products in the ternary catalyst system. DRS spectra indicated that compared with BiOI , the introduction of NiFe 2 O 4 and MWCNTs reduces the band gap energy of the NiFe 2 O 4 /MWCNTs/BiOI. The quenching test illustrates that h + , OH and O 2 − all functioned in the developed photocatalytic system, where O 2 − and h + play the dominant roles in DOX degradation. The more efficient electron-h + separation and more oxidizing species induced by UV light resulted in the significant improvement of DOX abatement in the developed coupling system compared with that on either BiOI or NiFe 2 O 4 /MWCNTs. The magnetic property of NiFe 2 O 4 /MWCNTs/BiOI enables its easy separation of the solid catalyst from the reaction solution and the sustainable application in the photocatalysis . Based on the intermediates of DOX decomposition identified by UPLC-MS, the possible degradation routes were proposed accordingly.
危险品化学品经营许可证（带存储）