Floating drones with 'hydrophilic teeth' tackle microplastic menace

The researchers shared their achievements in the scientific journal "Advanced Science". Thanks to "hydrophilic teeth", the floating drones can capture microplastics in the water.

Microplastics are tiny plastic particles that do not exceed 5 millimetres in size. In recent years, they have been found in tap and bottled water, rivers, lakes, oceans, and even human bodies. It is, therefore, possible that we drink and consume them daily. How did they get there? Through, for example, the degradation of more considerable plastic waste, the release of microbeads from cosmetic products, or the washing out of fibres from synthetic clothing during laundry. Introducing these particles into the natural environment poses a serious threat to humans and all aquatic organisms that may consume them, causing their accumulation in the food chain.

Separating fine particles requires the use of extremely dense screens and high pressure, which significantly reduces filtration efficiency. Furthermore, filtration techniques are unable to effectively clean large areas, such as lakes, rivers, or oceans.

The device, described in "Advanced Science", was created by Dr Seong Jin Kim and Dr Myoung-Woon Moon from the Centre for Extreme Materials Research at the Korea Institute of Science and Technology (KIST). They developed its hydrophilic design - the drone features gear-like protrusions with water-attracting properties, allowing for efficient microplastic collection. The drone moves independently and autonomously on water, like a robotic vacuum cleaner at home, enabling efficient cleaning of large bodies of water, such as oceans, lakes, or rivers. In tests, the drone recovered over 80% of microplastics, including expanded polystyrene, polypropylene, and polyethylene.

Sprout Studios, in collaboration with Draper and the Environmental Protection Agency (EPA), inspired by Korean research, also created the first underwater drone capturing microplastics, Draper, which aims to help combat microplastic pollution in oceans, coastal regions, and rivers.

How does it work? The drone scans the upper 9 metres of water, where most microplastics are found, identifies types of plastic, and transmits GPS data to a heat map. The project aims to create a plastic particle pollution index, similar to the World Air Quality Index, which will publish measurements and forecasts of microplastic concentration trends.

The drone has a large front intake that filters water and channels microplastics to an internal processing unit. Excess water is released from the back. Two proximity sensors on the sides of the intake communicate with a GPS antenna, aiding the drone in navigation. The outer ring houses the batteries, control unit, and inductive charger, and the open frame facilitates deployment and recovery. The drone is battery-powered and energy-efficient, and thanks to a self-docking wind-powered charging buoy, it is self-sustaining.

This drone uses "hydrophilic teeth" that attract water and use surface tension to gather microplastics of various sizes and shapes. It can operate autonomously and clean water like a robotic vacuum cleaner.

Innovative technologies, such as drones and specialised filtration systems, offer hope for more effective monitoring and removal of microplastics from our environment. Collaboration between scientists, government institutions, and technology companies is crucial for developing and implementing these solutions on a larger scale.