Environmental Science and Pollution Research

, Volume 25, Issue 10, pp 9331–9341 | Cite as

Mechanistic investigation of visible light driven photocatalytic inactivation of E. coli by Ag-AgCl/ZnFe2O4

  • Akhanda Raj Upreti
  • Nirina Khadgi
  • Yi Li
Research Article


In this study, photocatalytic inactivation of Escherichia coli was investigated over magnetic nanocomposite Ag-AgCl/ZnFe2O4. The nanocomposite demonstrated efficient photocatalytic activity by complete inactivation of the bacteria within 60 min of visible light irradiation. The anions HPO42− and SO42− were found to play the most important role in the inhibition of photocatalytic inactivation of E. coli. A systematic investigation of mechanism of photocatalytic bacterial inactivation was carried out based on cell membrane injury test, scanning electron microscopy (SEM) of bacterial morphology changes, Fourier transform infrared (FTIR) spectroscopy of E. coli cells before and after treatment, superoxide dismutase (SOD) and catalase (CAT) activity assay, and role of various reactive oxygen species (ROS). The activities of SOD and CAT enzymes were found to decrease due to the ROSs attacks during photocatalytic inactivation. The ROS produced in the photocatalytic disinfection severely altered the bacterial permeability and led to protein fragmentation, release of ions, and generation of protein carbonyl derivatives. The leaked cytoplasmic substances and cell debris were further degraded and, ultimately, mineralized with prolonged photocatalytic treatment.


Photocatalysis Bacterial inactivation E. coli Enzyme assay Water disinfection Magnetic nanocomposite 



The study was supported by National Natural Science Foundation of China (grant No. 91547105 and 51479066), Foundation for Innovative Research Groups of the National Natural Science Foundation of China (grant No. 51421006), Fundamental Research Funds for the Central Universities (grant No. 016B10614), Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYZZ16_0291).

Supplementary material

11356_2018_1225_MOESM1_ESM.docx (1.8 mb)
ESM 1 (DOCX 1794 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of EnvironmentHohai UniversityNanjingPeople’s Republic of China

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