Abstract Mesoporosity of about 7 nm in ETS-10 titanosilicate was generated by postsynthesis treatment with hydrogen peroxide under microwave irradiation, resulting in an increased external surface area of the materials (55 m2/g). The influence of titanosilicate porosity and its surface modification by phosphorus atoms (ET(P)S-10) on the retention of some nanoions (??-emitting radioactive U(VI) and Th(IV) ions) and biomolecules (the proteins cytochrome c, papain, and ??-globulin) was investigated.