Incorporation of hybrid elements into microporous titanosilicate ETS-10: An approach to improving its adsorption properties toward Pb2+

In this study, B-, Al-, and Ga-substituted microporous titanosilicate ETS-10 (designed as ETBS-10, ETAS-10, and ETGS-10, respectively) were synthesized under hydrothermal conditions. The adsorption kinetics and equilibria of Pb2+ ions on the ETS-10 (without substitution), ETBS-10, ETAS-10, and ETGS-10 samples were measured in a batch mode. Upon isomorphous substitution of B, Al and Ga for the Si(4Si) sites, the resulting solids exhibited more surface-negative charges as revealed by Zeta potential profile. The kinetic data showed a similar adsorption rate of Pb2+ on the four samples because of the same crystalline structure and the similar particle sizes of the four samples. However, the equilibrium results demonstrated that the maximum adsorption capacities of Pb2+ ions on samples ETBS-10, ETAS-10, and ETGS-10 were increased about 11%, 16.9%, and 12.5%, respectively, in comparison with ETS-10 because of the substitution of Si atoms by the trivalent elements.