Materials Chemistry and Physics, Vol.183, 467-475, 2016
Mild syntheses and surface characterization of amorphous TiO(OH)(H2PO4)center dot H2O ion-exchanger
This work focuses on the synthesis of titanium phosphate (TiP1) ion -exchanger containing solely H2PO4-groups. Based on the elemental analyses, TG, P-31 MAS NMR, XRD and Raman data, the formula TiO(OH)(H2PO4)center dot H2O is assigned to TiPI. The synthesis requires a mild heating at 70-80 degrees C for a short period of time, followed by filtration and HCI-washing of the TiP1 powder. The layered nature and low crystallinity of this sorbent is confirmed by powder XRD technique. The existence of micro and mesopores in the material is established using BET method. The Na+ capacity of TiP1 is determined to be 6.3 meq g(-1) which is the highest value reported for H2PO4-based sorbents. The presence of -H2PO4 groups is expected to considerably increase both the pH-working range of the TiP1 sorbent and its exchange capacity towards divalent metal ions. All data for TiPI are compared to the data for amorphous TiP containing mostly -HPO4 groups. (C) 2016 Elsevier B.V. All rights reserved.