Improvement of electron transfer efficiency during denitrification process by Fe-Pd/multi-walled carbon nanotubes: Possessed redox characteristics and secreted endogenous electron mediator

Nanomaterials which contacts microbial membranes for extracellular electron transfer, could establish a connection with the internal electron transfer chain of microorganisms. This characteristic could be employed to accelerate the denitrification process. In this study, the effect and mechanism of Pd-Fe/multi-walled carbon nanotubes (MWCNTs) on the extracellular electron transport behavior of Alcaligenes sp.TB was studied using electron transfer inhibitors and electrochemical methods. The main conclusions were as follows: the electron transfer site of Pd-Fe/MWCNTs was 266 mV, which was next to cytochrome c; the excellent electron exchange capacity of PdFe/MMWCNTs (Delta Ep = 734 mV) and the secretion of PN (33 mg/L) induced by Pd-Fe/MWCNTs both contributed to the occurrence of DEET process and promoted the electron transfer; the correlation between the electron mediator and the nitrate removal was analyzed were greater than 0.9731. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Nanomaterials in contact with microbial membranes can accelerate denitrification processes by establishing a connection with the internal electron transfer chain of microorganisms. This study found that Pd-Fe/MWCNTs promote extracellular electron transfer in Alcaligenes sp.TB. The excellent electron exchange capacity of Pd-Fe/MWCNTs and the secretion of PN contribute to the occurrence of DEET process and electron transfer.