Formation of a 10 A phase with halloysite structure under hydrothermal conditions with varying initial chemical composition

Abstract

A BSTRACT We studied the process of obtaining nanostructured halloysite by varying the parameters for creating the initial composition. The initial composition was synthesized by co-hydrolysis of (C 3 H 7 O) 3 Al and (C 2 H 5 O) 4 Si in the C 6 H 14 –NH 3 · H 2 O system. Aluminum hydrosilicate with the composition Al 2 Si 2 O 5 (OH) 4 was synthesized under hydrothermal conditions (220 ◦ C, 2 MPa, 96 h). Particles of plate-like morphology with average length 100 – 200 nm and 60 nm thickness were obtained. The PXRD patterns revealed the presence of two phases. Plate-like kaolinites are found. Also we observed the formation of a halloysite-like phase. Studies of synthesized samples by IR spectroscopy and thermal analysis revealed the presence of organic-modified hydrosilicate with phase transition around 412 ◦ C. The resulting phase is promising for studying the processes of adsorption and further exfoliation.