Synthesis and application of g-C3N4/Fe3O4/Ag nanocomposite for the efficient photocatalytic inactivation of Escherichia coli and Bacillus subtilis bacteria in aqueous solutions

Mitra Gholami,Ramin maleki,Roshanak Rezaei Kalantary,Soudabeh Ghodsi,Ali Esrafili,Hamid Reza Sobhi

doi:10.1186/s13568-021-01324-3

Abstract

Contamination of water with bacteria is one of the main causes of waterborne diseases. The photocatalytic method on the basis of bacterial inactivation seems to be a suitable disinfectant due to the lack of by-products formation. Herein, g-C3N4/Fe3O4/Ag nanocomposite combined with UV-light irradiation was applied for the inactivation two well-known bacteria namely, E. coli and B. subtilis. The nanocomposite was prepared by a hydrothermal method, and subsequently it was characterized by XRD, FT-IR, SEM, EDX and PL analyses. The optimum conditions established for the inactivation of both bacteria were as follows: nanocomposite dosage 3 g/L and bacterial density of 103 CFU/mL. In the meantime, the efficient inactivation of E. coli and B. subtilis took 30 and 150 min, respectively. The results also revealed that inactivation rate dropped with an increase in the bacterial density. It is also pointed out that OH˚ was found out to be the main radical species involved in the inactivation process. Finally, the kinetic results indicated that the inactivation of E. coli and B. subtilis followed the Weibull model. It is concluded that C3N4/Fe3O4/Ag nanocomposite along with UV-light irradiation is highly effective in inactivating E. coli and B. subtilis bacteria in the aqueous solutions.

Highlights

Given on-going growing population and climate change phenomena, provision of high quality and clean water from reused aqueous sources remains a great challenge (Widi et al 2018)
B. subtilis shows a high level of resistance due to the presence of a thick layer of peptidoglycan around it
The main difference between gram-positive and gram-negative bacteria arise from the cell wall and the amount of peptidoglycan membrane constituents (Al-Kobaisi, 2007)

Summary

Introduction

Given on-going growing population and climate change phenomena, provision of high quality and clean water from reused aqueous sources remains a great challenge (Widi et al 2018). The Weibull, Log-Linear, and Biphasic models were used to describe the kinetic behavior of the bacterial inactivation.

Results

Conclusion