Priority pollutants (Hg2+ and Cd2+) removal from water by ETS-4 titanosilicate

The synthetic microporous titanosilicate material ETS-4 has been used for the removal of Hg2+ and Cd2+ from water. Batch stirred experiments were carried out to study the equilibrium and the kinetics of the removal of Hg2+ and Cd2+ from water. It has been demonstrated that ETS-4 has a great affinity for both these metal cations even when their initial concentrations are low. The uptake rates for both Hg2+ and Cd2+ were well described by the pseudo-second order model which constants confirmed that the kinetics of the removal of Cd2+ is faster than that of Hg2+. However, at the equilibrium, ETS-4 has a higher capacity to remove Hg2+ than Cd2+. Adsorption isotherms for both Hg2+ and Cd2+ were well fitted to Langmuir isotherm and the corresponding monolayer capacities of ETS-4 are 0.43 and 0.24 µmol mg- 1, respectively, which are quite consistent with those predicted by the pseudo-second order kinetic equation. Hence, the contribution of this work is to support the use of this material for the removal of Hg2+ and Cd2+ from water.