Recaptured carbon dioxide may help us recycle batteries

Source: New Scientist

In a way that can assist with the recycling of metals from batteries, scientists from the University of Lyon, France, have come up with the chemistry to capture carbon dioxide (CO₂) from the air to extract the metals.

The process uses a mixture of polyamines which adsorb carbon dioxide readily. The scientists used carbon dioxide from the exhaust of an internal combustion engine to be fixated into a polyamine solution. As result, they gradually created a library of CO₂ loadings and solvents to assist with the precipitation of different metals.

They demonstrated that these metals could be extracted: lanthanum (La), nickel (Ni) and cobalt (Co). This shows that the three metal constituents of the La₂Ni₉Co alloys used to manufacture the batteries of electric vehicles can be separated and recovered by successive CO₂-induced selective precipitations.

This research shows that CO₂ can be captured sustainably as opposed to the capture and storage of CO₂ underground.

References:
- Captured carbon dioxide could be used to help recycle batteries. New Scientist, January 13, 2020.
-“Simultaneous CO₂ capture and metal purification from waste streams using triple-level dynamic combinatorial chemistry.” By J Septavaux, et.al. Nature Chemistry, 2020: https://doi.org/10.1038/s41557-019-0388-5

Could food ‘made from air’ let us ditch farms?

Source: New Scientist

A Finnish company called Solar Foods makes food ‘from air’. First, they used the electricity from solar panels to split water into hydrogen and oxygen. The resulting hydrogen provides energy to bacteria which can extract carbon dioxide (CO₂) and nitrogen from the air to make protein-rich organic matter. They do this more efficiently than plants grown via photosynthesis and the food is grown in vats in factories that take up much less land area than contemporary farms.

Food production is inefficient as less than 0.5% of the light energy falling on a field gets turned into food. By contrast, solar panels convert around 17% of the light energy falling on them into electricity. Solar Foods says it can turn electricity into food, via hydrogen, with an efficiency of 20%. (New Scientist)

Farming and land clearance produce a third of all greenhouse gases. Also, the clearing of land for farming reduces habitat for our wildlife. This process could help reduce the need for extra farmland and even allow some farms to return native habitat for the rewilding of endangered animals. This could be a more sustainable way to feed our growing population.

Read more: Can we really save the planet by making food ‘from air’ without farms? New Scientist, January 10, 2020.

CO₂ from beer-making used to feed productive algae and reduce emissions

Algal bio-reactor at Young Henrys. (ABC News)

When beer is fermented it releases carbon dioxide (CO₂). While crop cultivation and transport are a major part of the industry's emissions, the CO₂ from fermenting just one six-pack of beer takes a tree 2 days to remove it from the atmosphere. Conversely, green algae soaks up CO₂ quickly and makes ample oxygen (O₂) via photosynthesis. For example, a 400-litre bag of algae installed at a Sydney brewery (Young Henrys) is producing as much O₂ as a hectare of Australian bush. So here the fermenting process is putting O₂ into the air instead of CO₂.

The added bonus is that algae make sugars and other molecules from the photosynthetic process. These molecules are the building blocks for food, pharmaceuticals and plastic. The scientists of the University of Technology Sydney (UTS) managing the project at Young Henrys brewery have the aim to prove carbon emissions can be used to make commercial products. One advantage is that these algae need much less water to create food than say a crop of soybeans.

An example of a possible algal product is studied by Dr Janice McCauley who looks at using algae to make human supplements that can improve our health. Algae have the potential to do this because they have these molecules that could reduce inflammation in our bodies.

Read more:
- Every sixpack of beer contributes to climate change. Brewers hope algae is the solution. ABC News, January 15, 2020.
- Deep Green Biotech Hub, UTS: https://deepgreenhub.uts.edu.au/