Mercury Binding Sites in Thiol-Functionalized Mesostructured Silica International Nuclear Information System (INIS) Thiol-functionalized mesostructured silica with anhydrous compositions of (SiO2)1-x(LSiO1.5)x, where L is a mercaptopropyl group and x is the fraction of functionalized framework silicon centers, are effective trapping agents for the removal of mercuric(II) ions from water.