University of Tsukuba researchers have developed a new system for evaporating the water from algae biomass with reusable nanoporous graphene, which can lead to cheaper, more environmentally friendly biofuels and fine chemicals.

The team introduced a new procedure of harvesting energy and organic molecules from algae using nanoporous graphene and porous graphene foams. They have developed a reusable system that can evaporate water at high rate without the need for centrifugation or squeezing. The research has a great potential for the application of producing cleaner, cheaper, and more efficient biofuels, vitamins, and chemicals.

SEM image of N-doped graphene foam created from Ni foam-based CVD method after dissolving Ni foam with HCl solution. Image Credit: University of Tsukuba. Click image for the largest view

The team’s research and development work is described in a paper published in Advanced Sustainable Systems.

Algae biomass is a very exciting field of research, because they are photosynthetic microorganisms that convert light energy from the sun into energy-rich biomolecules. When algae are grown and harvested on an industrial scale, these molecules can be converted into a wide array of important compounds, including biofuel, medicines, omega-3 dietary supplements, and many other valuable bio-products.

Algae are also able to absorb carbon dioxide as they grow, switching from traditional fossil fuels to biofuels holds the promise of slashing net greenhouse gas emissions and recycling the CO2 back to fuel and other products. The problem has been micro-algae cultures consist primarily of water at low solid content (0.05 — 1.0 wt%). Harvesting the organic material due to solid-liquid separation techniques usually requires multiple dehydration steps.

The scientists at Japan’s University of Tsukuba introduced a new method for removing water from algae biomass that does not damage the fragile compounds to be harvested. In contrast with previous methods which rely on mechanical centrifugation or squeezing, while this approach uses solar irradiation and reusable, nanostructured support materials. The fabrication of hierarchically-structured nanoporous graphene and porous graphene foams creates tiny channels for water to be pulled upwards from deep inside the sample.

This newly developed material protects the biomass from overheating while capturing more of the sun’s energy to evaporate the water.

First author Professor Yoshikazu Ito said, “We needed a material that absorbs light, has a low specific heat and thermal conductivity, but is still hydrophilic and porous, with a large surface area. Fortunately, nitrogen-doped nanostructured graphene possesses all of these qualities.”

Senior author Dr. Andreas Isdepsky added, “The more energy efficient we can make the dehydration process, the more we can preserve the environmental benefits of using biomass in the first place.”

Algae may seem to have nearly disappeared in the face of the progress in crude oil discovery and natural gas production. But factually, the dehydration issue was a market killer. Too many expensive steps have been required to get to the molecules that matter and keep them intact. Years ago we saw many efforts to dry algae out. Perhaps this work will get the algae the market share it deserves with quality with a competitive price.

One can hope, algae remains a huge opportunity and potential economic disrupter.


1 Comment so far

  1. Terence on May 20, 2020 7:07 AM

    A very interesting area of research. Algae are already widely used in various fields of industry. The transition to biofuels will significantly have a positive impact on the environment.

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