A good number of people take spirulina as a dietary supplement, but researchers at the Swiss Federal Laboratory for Materials Science have found a way to coat blue-green algae in semiconductor compounds, triggering the tiny spirals to remove contaminants. some water. biofuels from its waste.

The algae coils are coated with a combination of nickel, zinc oxide and zinc sulfide which first developed into tiny fern-shaped structures, and was found to be effective in absorbing the solar energy. But by transferring the process to the spiral shape of the algae, a shading problem caused by the branches of the micro-fibers was avoided, resulting in greater light absorption.

The researchers coated four-micron spirals of preserved spirulina with a thin layer of nickel, then coated them with nanoparticles of zinc oxide and zinc sulphide. The magnetic properties of nickel proved to be a good way to recover the small coated spirals, while the zinc layer showed “impressive photocatalytic activity“.

The process was developed to help produce clean water using the purifying properties of plants, with a chemical reaction that oxidizes and neutralizes contaminants in the water when exposed to light. And the combination of zinc oxide and zinc sulfide nanoparticles allowed the team to tap into both the visible and ultraviolet portions of the solar spectrum to improve efficiency.

When the coated coils have completed their task of decontaminating the water, the zinc and nickel compounds can be recovered and reused. Then bioethanol and biodiesel can be produced from what is left. Leftover spirulina can also be pelletized and burned for energy, and the ash can be used as a fertilizer to grow new algae.

The Empa team says seaweed is relatively cheap and easy to producebecause they only need water, sun and fertilizer to reproduce quickly. In addition, single-celled organisms consume carbon dioxide and then release oxygen as waste, and the process is further enhanced by adding more CO2 to the algae culture.

So far, the process has only been successfully demonstrated in one lab, but researchers say they are confident larger-scale applications are possible and cost effective.

More information: www.empa.ch