Details

Autor(en) / Beteiligte

• Chen, Yuchen
• Yang, Jiayi
• Xiao, Lin
• Jiang, Lijuan
• Wang, Xiaolin
• Tang, Yuqiong

Titel

Role of Nano-Fe3O4 for enhancing nitrate removal in microbial electrolytic cells: Characterizations and microbial patterns of cathodic biofilm

Ist Teil von

• Chemosphere (Oxford), 2023-10, Vol.339, p.139643-139643, Article 139643

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Conductive magnetite nanoparticle (Nano-Fe3O4) can facilitate numerous biological reduction reactions as an outstanding electron mediator for electron transfer. The positive role of Nano-Fe3O4 for nitrate removal has gradually gained attention recent years, however, it has not been clarified for the persistence of the promoting effect under different concentrations addition. Performance of nitrogen removal and characteristics of cathodic biofilm were evaluated in this study after Nano-Fe3O4 addition with gradient concentration of 100∼500 mg L−1 in microbial electrolytic cells (MEC). Our study illustrated that the optimal concentration was 200 mg L−1 as the removal rate of nitrate increased by 24.76% and the removal rate of total dissolved nitrogen by 29.72%. At the optimal concentration, Nano-Fe3O4 increased cathodic biofilm DNA concentration by 61.04%, enhanced electron transport system activity, enriched iron redox bacteria, denitrifying bacteria and genes, as well as increased extracellular polymeric substances (EPS) amount, especially the protein content of soluble-EPS. However, promoting effect on nitrate removal was not visible in high concentration (500 mg L−1) addition, its electron transport system activity and EPS content were even declined. XPS results indicated that high concentration of Nano-Fe3O4 may reduce the availability of electrons to cathodic biofilm by competing for electrons, which inhibit nitrate removal. [Display omitted] •Nano-Fe3O4 optimally facilitated denitrification of cathodic biofilm at 200 mg L−1•Nano-Fe3O4 improved cell activity and electron transport system activity.•Nano-Fe3O4 increased amount and conductivity of extracellular polymeric substances.•Nano-Fe3O4 enriched iron redox bacteria, denitrifying bacteria and function genes.•High concentration of Nano-Fe3O4 showed no promoting effect on nitrate removal.