A biomimetic approach for separating microplastics from water

L. Hamann*, Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, Germany

Microplastics are small plastic particles and fibres. They result from the use of plastics in our everyday life or by weathering of plastic litter that is already in the environment. Each German emits about 4 kg microplastics per year. Due to its long persistence in the environment and its effects on organisms and ecosystems, it is perceived as a major environmental problem. In addition to political measures, eco-designed products, commitment and education of the civilian population, technical developments like filters are essential in order to reduce microplastic emissions. Hence, a biomimetic approach shall inspire new filter technologies, which can be implemented in the entry paths of microplastics. Following the biomimetic design process, suspension feeders are chosen as the appropriate biological models for particle separation. Suspension feeders are organisms that separate food particles from the surrounding water. Because of this ability, they are particularly affected by microplastics, as they confuse microplastics with their natural food. As biological filters, they serve as biological model and inspiration to develop biomimetic filter modules. After searching the literature, 24 suspension feeding types have been selected for further analyses. The mechanisms are described with biological and technical parameters and presented in a morphological box. Comparison is drawn to technical filters to identify similarities and differences, which leave room for innovation. Materials and their design, the combination of more than one separation mechanism and the combination of structure-function systems to sensory systems to adapt to changes in the environment show a high potential for a technical application. Examples are the silk nets of caddisfly larvae, the optimized fluid flow through the filtering pads in whale sharks and the filtering surfaces in the beak of flamingos. Through the systematic analysis, the results shall allow access to information about suspension feeders as biological model to facilitate the development a biomimetic filter module to reduce microplastic emissions.

Session: L9 - Short Oral Presentations II
Day: 23 October 2019
Time: 14:45 - 16:00 h

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