A team of international green chemists has managed to use cashew nutshells – a waste material – to produce sunscreens.
Scientists from the University of Witwatersrand have been working with colleagues from Malawi, Tanzania, and Germany on Xylochemistry.
Xylochemistry, also known as wood chemistry, is a chemical process that involves producing useful compounds from wood and other fast-growing non-edible plants.
The cashew nutshell sunscreen happens to be their latest work.
In their published paper in the European Journal of Organic Chemistry, the researchers described how they developed an aromatic compound with good UVA and UVB absorbance.
Aside from protecting humans and livestock, the new sunscreen can protect coatings and polymers from the sun’s harmful rays.
Since we already have products that offer that function, why do we need sunscreens from cashew nutshells?
Why Creating Cashew Nutshell Sunscreens is a Good Idea
Ultraviolet rays can damage most materials, leading to effects such as yellowing of plastics, weathering, discoloration of dyes, among others. In humans, UV exposure can lead to sunburns, premature aging, and the development of lethal melanomas.
That’s why we use organic and inorganic compounds as UV filters — to mitigate the damage caused by the sun.
An ideal organic ultraviolet ray filter has a high absorption of UVA rays (ranging from 315-400 nm) and UVB rays (280-315 nm).
For example, an organic compound called Oxybenzone is used to reduce the ultraviolet degradation in plastics. But, regulatory bodies are starting to enforce stricter regulations on the production of sun-filtering products.
While the petrochemical origin of the current UV protection agents is no cause for concern, the poor biodegradability is a significant drawback. As a result, they pose a real threat to the aquatic ecosystem.
In a statement, principal author of the paper, Charles de Koning of the Wits School of Chemistry, said:
“With the current concerns over the use of fossil resources for chemical synthesis of functional molecules and the effect of current UV absorbers in sunscreens on the ecosystem, we aimed to find a way to produce new UV absorbers from cashew nut shell liquid (CNSL) as a non-edible, bio-renewable carbon resource.”
Aside from saving the aquatic environment, the new sunscreen provides a sustainable and environmental-friendly way to use waste materials. Cashew nutshells are a waste product of cashew farming, and it’s abundant in countries like Tanzania.
The team has already filed a patent application to commercialize the process in South Africa.
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