Pyrolyzed sediment accelerates electron transfer and regulates rhodamine B biodegradation

Area of Science:

• Environmental Science
• Electrochemistry
• Microbiology

Background:

• Electron transfer efficiency is crucial for biodegradation of environmental pollutants.
• Exogenous electron shuttles can improve electron transfer in microbial electrochemical systems (MESs).

Purpose of the Study:

• To investigate the effect of sediment pyrolysis temperature on electron transfer and rhodamine B (RhB) removal in MESs.
• To explore the potential of pyrolyzed sediment as an electron mediator for pollutant degradation.

Main Methods:

• Sediment pyrolysis at various temperatures (300°C, 600°C, 900°C).
• Evaluation of electron transfer properties and power generation in MESs.
• Assessment of RhB removal efficiency.
• Microbial community analysis and metabolic pathway investigation.

Main Results:

• Sediments pyrolyzed at 300°C (PS300) and 600°C (PS600) enhanced power generation by 16%, while PS900 inhibited it.
• PS600 exhibited higher RhB removal efficiency compared to PS300, attributed to increased abundance of electroactive bacteria (EAB) and toxicity-degrading bacteria (TDB).
• PS600 upregulated amino synthesis and the tricarboxylic acid cycle, enhancing intracellular metabolism, while PS300 showed more active cellular anabolism potentially due to RhB toxicity.

Conclusions:

• Pyrolytic sediment, particularly at 600°C, effectively mediates electron transport and promotes pollutant removal in MESs.
• This approach offers a techno-economically feasible method for utilizing low-carbon solid wastes in environmental remediation.
• Optimizing pyrolysis temperature and understanding microbial community dynamics are key for efficient pollutant degradation.