Professor Zhiyong Jason Ren and Lu Lu.

A microbial photoelectrochemical system developed at Princeton University to obtain hydrogen from wastewater.

The need to flexibly manage non-programmable renewable energies makes hydrogen one of the technological elements on which the energy transition is based, like other storage systems.

But this gas also plays an essential role in other industrial fields: it is, for example, a critical element in the production of ammonia or methanol.

The only drawback is that obtaining pure hydrogen is an expensive process, which consumes large amounts of energy. Unless we use the method developed by Princeton University in New Jersey (USA).

There, a group of scientists succeeded in extracting hydrogen from wastewater using solar energy, in a process that has doubled the current conversion efficiency.

The technique, described in the article by Energy and environmental sciences, uses a special microbial electrolysis cell, a system that uses bacteria to break down organic matter. The element developed by the engineers is a chamber equipped with bioandes and a black silicon photocathode with a “Gruyère” interface. At the anode level, the microorganisms catalyze the oxidation of the organic substance using the electrode as an external electronic catalyst; at the cathode, by adding energy from the outside (in this case, solar) we obtain hydrogen.

Placed under sunlight and “loaded” with urban wastewater, the cell is capable of break down organic pollutants present during the production of solar fuel.

The process, the scientists explain, “allows us to treat wastewater and simultaneously generate fuel“.

For the experiment, the team, led by engineer Zhiyong Jason Ren, chose wastewater from a local brewery. This is the first time that real wastewater has been used in a microbial electrolysis cell and not in laboratory solutions specially created for testing.

The team produced hydrogen continuously for four days, where similar systems failed within hours.

“It’s a win-win process, both in the chemical industry and in other industries. They can save on wastewater treatment and energy consumption with this hydrogen generation system. “

Lu Lu, first author of the study.

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