An increasingly serious and widespread problem is the introduction of plastics into the water cycle. The poor degradability leads to the plastic waste remaining in the water for a long time and over time it fragments into smaller and smaller plastic particles, so called microplastics. Fields of application are microplastic sensitive seawater using process as membrane based sea water desalination, where microplastics poses a risk of membrane fouling or near food chain processes as sea salt production [1,2]. Another example is municipal and industrial wastewater, which is an important point source for microplastics in the environment. In a comparative study the effect of different types of water on and temperatures the fixation process using the three in previous studies best performing organosilanes were examined and compared with our results of further lab scale studies . We compared rinsed municipal wastewater, seawater and demineralized water at temperatures ranging from 7.5 – 40 °C. The residues of the organosilanes remaining in the water after the fixation process were monitored using ICP-OES and DOC measurements. Due to the fact, that microplastic encompasses a multitude of different types of polymers with different properties and surface properties, we compared the efficiency of the process for polyethylene, polypropylene, polyamide, polyester and polyvinylchloride as examples for common polymer types with different heteroatoms and polarities. The results will be presented in our talk. References [1] K. Schuhen, M.T. Sturm, Microplastic Pollution and Reduction Strategies, in: T. Rocha-Santos, M. Costa, C. Mouneyrac (Eds.), Handbook of Microplastics in the Environment, Springer International Publishing, Cham, 2020, pp. 1–33. [2] K. Schuhen, M.T. Sturm, A.F. Herbort, Technological Approaches for the Reduction of Microplastic Pollution in Seawater Desalination Plants and for Sea Salt Extraction, in: A. Gomiero (Ed.), Plastics in the Environment, IntechOpen, 2019.