Synergistic medium-chain-length polyhydroxyalkanoate-hydrochar composite anodes for stable, high-power microbial fuel...

Area of Science:

• Materials Science
• Electrochemistry
• Biotechnology

Background:

• Sustainable bioelectrochemical systems require advanced anode materials.
• Existing materials often lack a balance of high power output, structural integrity, and biodegradability.
• Medium-chain-length polyhydroxyalkanoates (mcl-PHA) offer biocompatibility and biodegradability.

Purpose of the Study:

• To develop and evaluate novel composite bioanodes integrating mcl-PHA with sugarcane bagasse-derived hydrochars.
• To compare the performance of these composites against a carbon-nanotube equivalent.
• To investigate the impact of hydrochar surface chemistry on bioanode performance.

Main Methods:

• Fabrication of composite bioanodes using mcl-PHA and functionalized hydrochars (raw, phosphate, sulfonated).
• Performance evaluation using polarization analysis and electrochemical impedance spectroscopy (EIS).
• Assessment of microbial fuel cell (MFC) performance, including open-circuit voltage, power density, and current density.

Main Results:

• The PHA-R composite achieved a high open-circuit voltage (938 mV) and power density (1.5 W/m²).
• PHA-P and PHA-S composites enhanced power and current generation compared to pristine hydrochars.
• Electrochemical analysis indicated reduced charge-transfer resistance in PHA-R and PHA-P composites.
• Post-operation, PHA-P and PHA-R showed high electrochemical activity, while PHA-S had minimal capacitance.

Conclusions:

• Composite bioanodes integrating mcl-PHA with hydrochars offer a promising route to high-performance, sustainable bioelectrochemical systems.
• Tailoring hydrochar surface chemistry and managing PHA biodegradation are crucial for long-term anode stability.
• The developed bioanodes demonstrate significant potential for microbial fuel cell applications.