Hydrothermal synthesis of nanotubular Mg-Fe hydrosilicate

Abstract

Magnesium iron hydrosilicate nanotubes with a chrysotile ((Mg,Fe)3Si2O5(OH)4) structure have been synthesized hydrothermally at t = 250–450°C and p = 30–100 MPa. In the hydrothermal synthesis of (Mg,Fe)3Si2O5(OH)4 chrysotile, part of the Fe2+ ions oxidize to Fe3+ and are incorporated into the octahedron and tetrahedron layers of the chrysotile structure. The limiting iron content of chrysotile has been determined up to which cylindrically rolled layers can form to yield nanotubes. The hydrothermal treatment of precursors richer in FeO yields platelike hydrosilicates. The iron ions present in the starting components affect the synthesis parameters, morphology, size, optical properties, and thermal stability of the nanotubes.