Competitive removal of Cd2+ and Hg2+ Ions from water using Titanosilicate ETS-4: kinetic behaviour and selectivity
1000 | 2013
Cardoso, Simão P. | Lopes, Cláudia B. | Pereira, Eduarda | Duarte, Armando C. | Silva, Carlos M.
Mercury and cadmium are priority hazardous substances. Some titanosilicates have been tested for the removal of Cd2+ and Hg2+ from single solutions by ion exchange. In this work, the competition between both contaminants for the exchanger binding sites of titanosilicate Engelhard titanosilicate material number 4 (ETS-4) was studied by performing batch experiments with aqueous solutions containing the two counter ions. The results evidenced the large capacity of ETS-4 and shown that the cadmium(II) diffusivity through the sorbent is higher than that of mercury(II). Furthermore, the ETS-4 exhibited higher kinetic and equilibrium selectivities for Cd2+, which attained values in the ranges 8.9-12.5 and 7.9-12.8, respectively. With respect to modelling, the pseudo-second-order equation described successfully the competitive removal of Cd2+ and Hg2+.
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