Meet the Chinese fish robots that can ‘eat’ microplastics – and maybe help clean up oceans
- Small bots developed by researchers at Sichuan University absorbed plastic pollutants in tests in shallow water
- The next step is to see if they can do it at greater depths and analyse the contaminants in real time
It’s small, soft, eats microplastics and, with time, might be able to analyse marine pollution in real time.
In a study published in the peer-reviewed journal Nano Letters on June 22, researchers from Sichuan University in southwest China said the robot could also “self-heal” and absorb microplastics even when damaged.
For now, the soft robot only collects microplastics in the shallows.
Mussels, lobsters and oysters: microplastic pollution finds way into 170 different types of Hong Kong seafood
But Wang Yuyan, one of the lead authors of the study, said the team was working on new materials that could work underwater and detect microplastic contaminants in real time – and one day maybe help stop the pollution.
“To further clarify the danger of microplastic composite pollutants, we believe that it is of great significance to develop a micro-sampling robot to accurately collect these harmful microplastic composite pollutants in the aquatic environment,” Wang said.
“It is expected that in the future, we can directly put these ‘fish’ into the ocean, directly collect and analyse the composition of microplastics in the ocean, and then guide the design of the processing and production of our plastic products, blocking the generation of microplastics from the source.”
Microplastics are plastic fragments less than 5mm long and can be easily ingested by a range of marine life, harming their health.
According to an estimate by Kyushu University in Japan in 2021, there are 24.4 trillion pieces of various microplastics in the world’s upper oceans, equivalent in weight to about 30 billion 500-millilitre (17 fl oz) plastic water bottles, but the actual amount is likely to be much greater.
The robot fish designed by the Sichuan University researchers is about 1.3cm (½ inch) long and is propelled by a near-infrared laser that deforms the material on the bot’s tail.
The robot can swim up to 2.67 body lengths per second, a speed that outperforms most artificial soft robots, according to the researchers.
The bot’s material is made from layers and layers of nano sheets of a chemical mixture that includes graphene.
The structure makes the material more bendable and durable and was based on the formation of nacre found in clam shells, the researchers said in the paper.
03:15
Microplastics and debris from burning ship washes onto Sri Lankan coast
They said that because some components in microplastics had solid chemical bonds and electrostatic interactions with the fish material, the robot could repeatedly absorb nearby microplastics and transport them to a designated place.
The researchers noted that the nanocomposite material in the robot had a self-healing efficiency of up to 89 per cent, so the robot could absorb pollutants and “recover its robustness and functionality even when damaged”.
The next step, the research team said, would be to test to see if the fish-shaped robot could work at a greater depth to deal with the microplastic waste lurking in the deep sea.
