Wastewater fuel cell removes 99.99% of antibiotics and makes hydrogen peroxide

Researchers have built a single, binder-free electrode that turns a Microbial Fuel Cell (MFC) into a multi-tasking system. It uses bacteria in municipal wastewater to generate electricity while simultaneously degrading a stubborn antibiotic and producing a valuable industrial chemical.

Hungry bacteria digest organic waste in the wastewater and release electrons into the system. These flowing electrons help degrade 99.99 percent of the antibiotic within two days.

Rather than generating plain water at the counter electrode, the process diverts the chemical pathway to synthesize hydrogen peroxide alongside a modest electrical current. Hydrogen peroxide is a oxidizing and disinfecting agent used in healthcare, environmental management, household cleaning, and manufacturing.

This multi-tasking approach demonstrates how complex municipal sewage can simultaneously yield cleaner water, industrial chemicals, and renewable power.

“The designed MFC was not only for treating the wastewater but also coupled simultaneous antibiotic removal and hydrogen peroxide generation,” the researchers noted in the study paper.

Graphical abstract. Credit: Journal of Power Sources

Hydrogen peroxide generation

Sewage is packed with organic matter and resilient pharmaceutical pollutants like chloramphenicol that treatment facilities fail to break down.

A team of researchers in India transformed this environmental hazard into a resource by using a novel microbial fuel cell equipped with a custom iron-nickel carbon nanofiber electrode. Through microbial fuel cells, wastewater can be treated to produce bioenergy simultaneously.

A microbial fuel cell normally uses bacteria that consume organic waste to generate electrons, which combine with oxygen at a second electrode to produce plain water.

Researchers altered this standard pathway using a custom binder-free electrode made of iron and nickel oxide-tipped carbon nanofibers on flexible carbon cloth. This design forces incoming electrons down a shorter, two-electron path that stops the reduction halfway.

The cell synthesizes valuable hydrogen peroxide instead of basic water. This process produces an industrial disinfectant and avoids energy-intensive traditional manufacturing methods.

Antibiotic removal

Testing on raw sewage spiked with 50 milligrams per liter of chloramphenicol showed the prototype’s high efficiency over a few hours.

The electrified biological system achieved a triple benefit by removing 99.99 percent of the chloramphenicol and cutting chemical oxygen demand by 94 percent.

Bacteria digesting the organic waste drove these high treatment rates, vastly outperforming passive control tests. At the same time, the system produced 0.74 mM hydrogen peroxide and maintained a steady electrical current and an open-circuit potential above 0.6 V.

“Following the performance, the unified FeNiO-CNF/ACF electrocatalyst-based MFC emerges as a promising, economically viable, energy-efficient, and sustainable wastewater treatment, recalcitrant pollutant removal, and fuel generation system in a complex environment simultaneously,” the researchers noted in the study paper.

Challenges remain. The overall power output is still small, typical of benchtop microbial fuel cells, and the team is currently studying the toxicity of the antibiotic’s breakdown products. Scale is another hurdle; the laboratory cell handled just 250 milliliters per chamber.

Long-term durability remains a primary concern when deploying metal-oxide tips in continuous wastewater treatment. Extended exposure to raw sewage exposes the catalyst to corrosive chemical compounds and dense biological accumulation, which can block active sites over time.

The findings were published in the Journal of Power Sources.