Remoción de Cr(III) por adsorción en arcillas pilreadas

C. ADAMO; F. ESPINOZA; E. L. SHAM; E. M. FARFÁN TORRES

Mar del Plata, Argentina

Congreso; V Congreso Iberoamericano de Física y Química Ambiental; 2008

Sociedad Iberoamericana de Física y Química AMbiental

The potentiality of the use of TiO2 pillared clays as sorbents for the removal of Cr (III) was evaluated. The TiO2 pillared clays were obtained by intercalation of two Argentinian montmorillonites suspensions without previous treatments (PJ and PESP) and homoionized with sodium (PJ-Na and PESP-Na), with a mixture of titanium isopropoxide and HCl with a molar ratio Ti/Cl of 1:2. The obtained results show that the pillaring process leads to the obtention of materials with an interlayer space between 22 and 23 Ã, independently of the departure clay used. That is to say that only the clay phase interacts with the olygomers precursors of the props of TiO2. The adsorption batch essays of Cr(III) in aqueous solution show that the stationary state is reached after 5 hours of time of contact. The values of maximum adsorption capacity obtained by means of the Langmuir model, are between 9.2 and 7.4 mg of Cr3+/g of clay. Although they are lower than the correspondents to the original clays, they are still superior to the values reported in the literature for other sorbents. The decrease of the adsorption capacity in case of the pillared clays is due to the fact that a part of the exchange sites of the clays are effectively covered in an irreversible form by the microparticles of TiO2 inserted between the plates. The pillared materials calcined at 500°C adsorbed a lower quantity of Cr3+ due to the partial collapse of their structure with the consequent decrease of accessibility to the exchange sites.2 pillared clays as sorbents for the removal of Cr (III) was evaluated. The TiO2 pillared clays were obtained by intercalation of two Argentinian montmorillonites suspensions without previous treatments (PJ and PESP) and homoionized with sodium (PJ-Na and PESP-Na), with a mixture of titanium isopropoxide and HCl with a molar ratio Ti/Cl of 1:2. The obtained results show that the pillaring process leads to the obtention of materials with an interlayer space between 22 and 23 Ã, independently of the departure clay used. That is to say that only the clay phase interacts with the olygomers precursors of the props of TiO2. The adsorption batch essays of Cr(III) in aqueous solution show that the stationary state is reached after 5 hours of time of contact. The values of maximum adsorption capacity obtained by means of the Langmuir model, are between 9.2 and 7.4 mg of Cr3+/g of clay. Although they are lower than the correspondents to the original clays, they are still superior to the values reported in the literature for other sorbents. The decrease of the adsorption capacity in case of the pillared clays is due to the fact that a part of the exchange sites of the clays are effectively covered in an irreversible form by the microparticles of TiO2 inserted between the plates. The pillared materials calcined at 500°C adsorbed a lower quantity of Cr3+ due to the partial collapse of their structure with the consequent decrease of accessibility to the exchange sites.