MELBOURNE, Dec 13 ― With COP28 drawing to a close, we take a look at some of the most surprising and most promising ways to reduce greenhouse gas emissions and combat plastic pollution featured in scientific publications over the course of 2023.

The use of rainwater to generate electricity

In the near future, rain panels may be as numerous as solar panels on the roofs of houses. Chinese researchers at Tsinghua University have developed a device for generating energy through the impact of raindrops. While the technique of transforming water into a source of energy isn't new, its application with raindrops remains anecdotal at this time due to the small quantities it generates.

It's precisely this point that the researchers are working on optimising. They have developed a device whose energy output would almost match that of a solar panel, at 200 watts per square metre. These panels have only just been developed, and are therefore not yet on the market. However, we can already imagine the success of such an innovation with manufacturers and homeowners, especially in regions of the world where rainfall is high.

Coffee grounds for stronger concrete

Last August, researchers at the Royal Melbourne Institute of Technology in Australia published a study demonstrating the effectiveness of coffee grounds in improving the performance of concrete as a building material. This environmentally-friendly solution could theoretically enable highly polluting everyday organic waste to be recycled while reducing the quantity of other, often precious resources used, including sand. But coffee grounds are not the only ingredient being used to make concrete more resistant and more ecological. Researchers in Japan came up with the idea of adding a substance to cement, obtained from used baby diapers, that can serve as a binder to improve the quality of concrete while reducing its carbon footprint. The idea has double utility, since it has also been designed to reduce the pollution and waste associated with these everyday household products.

To test their theory, the researchers conducted a laboratory experiment to calculate the number of disposable diapers that could be used in materials for building a low-cost, 36-square-metre dwelling, meeting construction standards in Indonesia. According to the researchers, the substance recovered from used diapers can be used to a maximum capacity of up to 10 per cent in concrete used to build structural elements (such as load-bearing columns or beams) and up to 40 per cent for non-structural components, such as floors or partition walls.

Using fly carcasses to produce biodegradable plastic

Plastic production generates significant greenhouse gas emissions and is a huge source of pollution. To reduce the carbon footprint and waste associated with plastic consumption, American researchers at A&M University in Texas have recovered waste from the breeding of "black soldier” flies as the larvae are rich in protein and nutrients to make biodegradable plastic. The carcasses of the insects contain chitin, a non-toxic, biodegradable sugar-based polymer also found in the shells of crustaceans such as crabs and shrimps.

After rinsing, demineralising and bleaching the chitin extracted from the adult flies' bodies, the researchers propose using it to create materials such as polycarbonates or polyurethanes, types of plastic that are currently polluting because they are manufactured from petrochemical ingredients. Chitin from fly carcasses has other promising uses. Other researchers working in the same university laboratory have created a hydrogel from chitin, capable of absorbing 47 times its weight in water in just one minute. "This product could potentially be used in cropland soil to capture floodwater and then slowly release moisture during subsequent droughts,” note the researchers. ― ETX Studio