Abstract: Use of an alkyltrichlorosilane of the following formula I: R—SiCl3, wherein: R represents an alkyl group, Si represents a silicon atom and Cl represents a chlorine atom, and/or of a silsesquioxane of the following formula II: [RSiO3/2]n, wherein: R represents an alkyl group, Si represents a silicon atom, O represents an oxygen atom and n represents an integer, for the removal of microplastic particles from water and/or for the treatment of water. Further, a method for the removal of microplastic particles from water and/or for the purification of water is provided, as well as an inclusion and/or intercalation compound, a kit for the removal of microplastic particles from water and/or for the purification of water as well as a water treatment system.