Role of dissolved organic matter from natural biofilms in oxytetracycline photodegradation
- 137 Downloads
Dissolved organic matter (DOM) is one of the most important factors that influence the photodegradation of antibiotics in the aquatic environment. However, the mechanisms by which DOM produced by natural biofilms (BDOM) influences photodegradation are poorly understood. Here, the influences of BDOM and fulvic acid (FA) as model DOM on the photodegradation of the antibiotic oxytetracycline (OTC) were investigated, and the differences between the characteristics of BDOM and FA were determined by ultraviolet, infrared, and three-dimensional fluorescence spectrum analyses. In addition, an experiment on the scavengers of reactive oxygen species (ROS) was also conducted to explore related mechanisms. The results indicated that the aromaticity degree and molecular weight of BDOM were lower than those of FA. The OTC photodegradation rates increased from 9.7 × 10−2 to 19.9 × 10−2 min−1 with increasing BDOM concentration, while they decreased from 8.9 × 10−2 to 5.6 × 10−2 min−1 with increasing FA concentration. Excited triplet-state BDOM (3BDOM*) and singlet oxygen (1O2) simultaneously promoted the photodegradation of H2OTC and HOTC−. However, FA inhibited OTC photodegradation through strong light-shielding effects. These results are beneficial for understanding the effects of natural biofilms on the antibiotic photodegradation in the aquatic environment.
KeywordsAntibiotic Photochemical degradation Reactive oxygen species Humic substance Periphyton Algae
This study was supported by the National Natural Science Foundation of China (Nos. 21577047 and 21307041), and the 111 Project (No. B16020).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Arce VB, Scotto J, Allegretti PE, Melo MA, Airoldi C, Salum ML, Erra-Balsells R, Diez RP, Martire DO (2016) Combined experimental and computational investigation of the fluorescence quenching of riboflavin by cinnamic alcohol chemisorbed on silica nanoparticles. J Phys Chem C 118:15348–15355CrossRefGoogle Scholar
- He XS, Xi BD, Wei ZM, Jiang YH, Yang Y, An D, Cao JL, Liu HL (2011) Fluorescence excitation-emission matrix spectroscopy with regional integration analysis for characterizing composition and transformation of dissolved organic matter in landfill leachates. J Hazard Mater 190:293–299CrossRefGoogle Scholar
- Huber S, Remberger M, Kaj L, Schlabach M, Jorundsdottir HO, Vester J, Arnorsson M, Mortensen I, Schwartson R, Dam M (2016) A first screening and risk assessment of pharmaceuticals and additives in personal care products in waste water, sludge, recipient water and sediment from Faroe Islands, Iceland and Greenland. Sci Total Environ 562:13–25CrossRefGoogle Scholar
- Zhao C, Pelaez M, Duan X, Deng HP, O’Shea K, Fatta-Kassinos D, Dionysiou DD (2013) Role of pH on photolytic and photocatalytic degradation of antibiotic oxytetracycline in aqueous solution under visible/solar light: kinetics and mechanism studies. Appl Catal B Environ 134–135:83–92CrossRefGoogle Scholar