Application of magnetic multi-wall carbon nanotube composite into fermentative treatment process of ultrasonicated waste activated sludge

[Display omitted] •Fe3O4-MWCNTs achieved better WAS conversion, to H2, than Fe3O4 and MWCNTs.•Fe3O4 NPs could enrich hydrogenase, while MWCNTs raised sludge conductivity.•Fe3O4 NPs exhibited higher substrate degradation efficiency than MWCNTs.•Because of released ROS, Fe3O4 revealed sharper toxicity...

Full description

Saved in:
Bibliographic Details
Published in:Bioresource technology 2020-06, Vol.306, p.123186-123186, Article 123186
Main Authors: Mostafa, Alsayed, Tolba, Aya, Gar Alalm, Mohamed, Fujii, Manabu, Afify, Hafez, Elsamadony, Mohamed
Format: Article
Language:English
Subjects:
Enzymes activity
Fe3O4-MWCNTs composite
Reactive oxygen species
Sludge conductivity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:[Display omitted] •Fe3O4-MWCNTs achieved better WAS conversion, to H2, than Fe3O4 and MWCNTs.•Fe3O4 NPs could enrich hydrogenase, while MWCNTs raised sludge conductivity.•Fe3O4 NPs exhibited higher substrate degradation efficiency than MWCNTs.•Because of released ROS, Fe3O4 revealed sharper toxicity than MWCNTs.•Fe3O4-MWCNTs showed low ROS likely due to limited reaction of restricted Fe3O4. This study investigated the effect of supplementing nano-sized magnetite (Fe3O4 NPs), multi-wall carbon nanotubes (MWCNTs) and Fe3O4-MWCNTs composite on bioconversion of waste activated sludge to hydrogen, in batch systems. Substrate degradation efficiency (SDE) increased from 28 ± 3.8 (control) to 49 ± 5.9, 46 ± 4.8 and 52 ± 6.3% at optimal doses of 200 (Fe3O4 NPs), 300 (MWCNTs) and 200 mg/L (Fe3O4-MWCNTs), respectively. Based on dissolved iron and sludge conductivity measurements, superior SDE in Fe3O4 and MWCNTs batches have been assigned to enhanced dissimilatory iron reduction (DIR) and high sludge conductivity, respectively. Combined impacts for sludge conductivity and DIR were revealed in Fe3O4-MWCNTs system. In 200 mg/L (Fe3O4-MWCNTs) batch, catalytic activities of hydrogenase, protease and α-amylase peaked to 596, 146 and 131% (relative to control), respectively; as well as, highest volumetric H2 production of 607 ± 59 mL/L was acquired. Performance deteriorations at high concentrations of nanoparticles were caused by cellular oxidative stress induced by generated reactive oxygen species.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2020.123186