Plastic microparticles in water are becoming a growing problem in the environment. A new filtration system was developed by the Fraunhofer Silicon Photonics Center and its partners to make it faster and easier to monitor lake and river pollution. With the support of the German Federal Institute for Materials Research and Testing (BAM), the goal of the research project is to establish a database to analyze the pollution of lakes and rivers and to control the pollution.
Photomicrograph of a prototype silicon filter with a 50 μm laser micromachining (Fraunhofer CSP)
Optical micrograph of the prototype silicon filter after laser micromachining, with a pore size of approximately 50 μm (Fraunhofer CSP).
The invasion of plastic particles into the ecosystem has become an increasingly serious environmental problem. The way these particles enter lakes, rivers and wastewater is not completely clear. In addition, there is no suitable standardized method to study and detect plastic particles in water. However, a reliable scientific database on the origin, occurrence and impact of plastic particles in the environment is essential to solving environmental problems.
The German federally initiated research project "Representative diagnostic strategies for comprehensive systems to understand the specific entrainment of plastics into the environment (RUSEKU)". The goal of the Materials Research and Testing Institute (BAM) is to develop a diagnostic method by 2021 to enable faster and more standard measurement of particle entrainment in lakes and rivers. It will also allow identification of locations where the microplastic particles of water are particularly contaminated.
Fast standardized measurements
As part of a joint research project, the Fraunhofer Silicon Optoelectronics Center CSP is working with SmartMembranes GmbH to develop a special filtration system as part of a standardized and simple sampling method. The cascade filtration system will use special silicon filters with a defined pore density and size to capture plastic particles.
"The sampling method is a key factor in obtaining reliable conclusions about the microplastic volume of groundwater, drinking water, and wastewater or surface water. A sampling scheme is planned to make a significant contribution to this," said Christian Hagendorf, who is responsible for the research project of Fraunhofer CSP , Said the doctor. "Laser and chemical etching processes will be used to make the appropriate hole size on the silicon substrate, where particles will be retained on the silicon substrate. In later analysis in the laboratory, we will use infrared in a wide wavelength range in the transmission method The chemical composition of transparent silicon under the light, and the microplastic particles located on it can be seen by spectrometric techniques, "Hagendorf added.
Apply Optimized Filtering System
Another important parameter that affects the quality of the filter is the mechanical strength of the filter. During the sampling process, the mechanical strength of the filter must carry the load caused by the water flow without breaking. In addition, filters need to have intelligent, optimized pore geometry and surface finish. Another goal of this work is to define the working procedures from sampling to cleaning, to analyzing microplastic particles with partners. This "smart sampling" should enable the fine plastics detection-from sampling to rapid analysis-to be well-adjusted.
This effective and reliable microplastic sampling method will lay a good foundation for strategies and measures to reduce microplastics in the water cycle. This joint research project is funded by the Federal Ministry of Education and Research (BMBF) as part of the research topic "Plastics in the Environment". In addition to Fraunhofer CSP, six scientific research institutions and three SMEs participated in the project.
About Silicon Photovoltaic Fraunhofer CSP Center
Fraunhofer CSP is engaged in application research in the fields of silicon crystallization, solar module technology and solar wafer production. The institute develops new technologies from ingot production to module production, and also participates in the development of new materials in the value-added chain. Another research focus is the evaluation of solar cells and modules, and the characterization of electrical, optical, and microstructured materials and components. Fraunhofer CSP is a joint research organization of the Fraunhofer Institute of Microstructure and Systems IMWS and the Fraunhofer Institute of Solar System ISE.
SmartMembranes Company Profile
SmartMembranes GmbH is a branch of the Fraunhofer Institute of Microstructure and Systems IMWS and was established in 2009 in Halle (Saale). The company describes itself as the world's leading manufacturer of high-order porous materials of alumina and silicon. The high-order porous materials of silicon have clear adjustable membrane characteristics and structural parameters, which are suitable for many innovative applications. In addition to producing materials to customer specifications, another major pillar of the company's business is the development of new processes and products around its core business.