A crab wanders on a beach contaminated with plastic pellets. Images: VCG
A group of Chinese scientists have developed a type of ion exchange microrobot to remove microplastics and nanoplastics (MNPs) from water, according to Jinan University, one of its developers.
The robot has a diameter of 20 to 100 microns, which is thinner than a human hair. It has innovative means of obtaining energy, taking advantage of exchanges with impurities in water, and can operate without additional energy input.
The research, which was recently published in the journal Science Advances, indicates that micronutrient powder pollution in non-marine waters poses a major threat to the global ecosystem. However, current strategies, such as chemical flocculation and physical filtration, often fail to completely remove ultrafine plastic particles.
In search of a better solution, scientists from Guangzhou-based Jinan University and the University of Hong Kong designed microbots to remove MNPs from water, inspired by land-sweeping robots.
“Floor-sweeping robots can run autonomously on a planned route and sweep garbage nearby, so we thought there could be a similar type of robot for cleaning garbage in water,” said Wang Jizhuang, a senior researcher from Jinan. University.
The self-propelled robots developed by the group consist of resin globules with magnetic nanoparticles, and can interact with surrounding particles as they move, resulting in the dynamic removal of micronutrients in their path. Wang said each robot has an absorption band of up to 200 microns in diameter.
Meanwhile, the plastic being sucked into the water causes a fluid to flow around the robots, causing them to move independently without any other energy input.
Due to the magnetic components inside, the robots can also be collected simply with a magnet after completing their tasks, and can be precisely controlled through a programmable magnetic field, according to Wang.
In their research, it has been confirmed that the robots show a removal efficiency of more than 90 percent during 100 consecutive tasks to remove MNPs of different compositions, sizes, and shapes in water.
It is estimated that each liter of wastewater only needs about 5 million such micro-robots to clean up the MNPs contained in the water, Wang said, adding that this number is very easy for micro-robots to achieve in practice.
The group has identified additional research goals, such as finding ways for newly developed robots to simultaneously collect MNPs and break them down on site.
It is hoped that the development of self-propelled robots, with advantages of reasonable cost and minimal secondary pollution, will make them suitable for industrial applications, providing an attractive strategy for large-scale removal of ultra-fine plastic particles, he said.
In August 2022, the China Institute of Electronics published a report on the development of the robotics industry, estimating that the global market size of the robotics industry will reach $51.3 billion by the end of 2022, and may break 65 billion yuan in 2024.
China’s robotics industry market size is expected to reach $17.4 billion by the end of 2022, with the average annual growth rate between 2017 and 2022 reaching 22%.
The industrial robot has reached a new historical high as it has been applied in plastic engineering, chemical engineering, metal products and automobile manufacturing.
Data from the International Federation of Robotics showed that China’s industrial robot market size has been growing in the past five years and will expand the trend of increase in 2022 to $8.7 billion, surpassing $11 billion in 2024.
Xinhua – Global Times
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