Effect of Fe₃O₄ nanoparticles on the performance of anaerobic digestion through electrochemical analysis

ABSTRACT

In view of the high cost and complex operation of the traditional chemical method for the determination of the anaerobic digestion (AD) process, this study investigated the feasibility of using electrochemistry analysis to determine the effect of Fe₃O₄ nanoparticles (NPs) on the AD process. The quantity of electric charge of Fe₃O₄ NPs modified graphite electrode in sodium acetate electrolyte was higher than that of graphite electrode. The addition of Fe₃O₄ NPs was beneficial to improve the electrochemical activity of the electrode. On this basis, enzymes and microorganisms were extracted from anaerobic reactors containing different concentrations of Fe₃O₄ NPs to make electrodes respectively to further investigate the effects of Fe₃O₄ NPs on enzyme and microbial activities in AD. The electrochemical analysis results of the enzyme electrodes and microbial electrodes showed that the quantity of electric charge produced by the group of 200 mg/L Fe₃O₄ NPs was the highest. The cumulative biogas production of 200 mg/L Fe₃O₄ NPs was 809 mL/g VS, and better than other groups. These results showed that 200 mg/L Fe₃O₄ NPs was the best dosage, and the electrochemical analysis has higher sensitivity in the AD detection.

Highlight

1. Electrochemistry was used to investigate the activities of enzymes and microorganisms in anaerobic digestion.

2. The effects of Fe₃O₄ nanoparticles on different stages of anaerobic digestion were analyzed by electrochemical method.

3. The feasibility of electrochemical analysis was verified from the perspective of microbiology.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electrochemistry
• Fe₃O₄ NPs
• anaerobic digestion
• electrode
• electrochemical analysis

Data availability statement

All data generated or used during the study are available from the corresponding author by request.

Disclosure statement

No potential conflict of interest was reported by the authors.