Pore size control for mesoporous titanium hydroxide prepared with mixed template molecules and its fluoride ion exchange property

Control of pore size on mesoporous titanium hydroxide denoted as TiOX(OH)2+δ with zirconium additive was studied by using different size template molecules. The mesopore diameter of TiOX(OH)2+δ increased monotonically with increasing size of the organic template molecule used. The use of a mixture of template molecules with different size allowed for accurate pore size control of TiOX(OH)2+δ. Moreover, a pore size between those of single template molecules was obtained using a mixture of two different template molecules. The fluoride ion exchange capacity of Zr-added TiOX(OH)2+δ also increased with increasing mesopore diameter, and the largest fluoride ion exchange capacity was achieved on the sample with 3.34 nm pore size, and the fluoride ion exchange capacity was further improved by the accurate control of pore size. The amount of fluoride ions adsorbed was 1.1 mmol/g against 50 ppm NaF solution; this was observed in TiOX(OH)2+δ with 4.2 nm pore size, which was obtained using a 3:1 mixture of C12H25NH2:C14H29NH2 as the template molecule.