Estudios de adsorción de Pb en una montmorillonita pilareada con SiO2-Cr2O3

A. MERCADO; 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

In the present work the use of an Argentine montmorillonite pillared with SiO2-Cr2O3 nanoparticles as a sorbent for the removal of Pb the (II) was evaluated. In the pillaring process 3-amine-propyl-triethoxysilan (APTEOSi), silicon tetraethoxide (TEOS), and chromium (III) nitrate, were used as precursors of the mixed pillars. The clays calcined at 500ºC were named PESPSiCr-01 and PESPSiCr-03 respectively. The basal spacings for the calcined clays were 9,56 Å (PESP-Na), 32 Å (PESPSiCr-01) and 15,38 Å ( PESPSiCr-03). The FTIR demonstrate the presence of bands attributed to stretching modes typical of this type of materials. The obtained results show that the clay PESPSiCr-01 calcined at 500ºC is completely deshydroxylated, whereas in the PESPSiCr-03 this process still does not take place. The batch adsorption process for Pb2+ and Pb2+ in the presence of Ca2+ was studied, in aqueous media and room temperature. The results show that the adsorption behavior of can be described by the Langmuir model. The qmax for Pb2+ reaches values of up to 139,1 mg Pb2+/g clay. The FTIR studies indicate that the clay sheet structure was not altered during the Pb2+ adsorption. The Eads determined from the model of Dubinin-Raduskevich, corresponds to 33,3 kJ/mol, which would indicate that the process of retention takes place basically by means of ionic exchange reactions at the surface sites located at the clay layered surface, the nanoparticles and the clay borders. The pillared clay presents pronounced affinity towards the Pb(II) adsorption still in the presence of Ca2+, with a factor of separation, α2, of 2,58. 2-Cr2O3 nanoparticles as a sorbent for the removal of Pb the (II) was evaluated. In the pillaring process 3-amine-propyl-triethoxysilan (APTEOSi), silicon tetraethoxide (TEOS), and chromium (III) nitrate, were used as precursors of the mixed pillars. The clays calcined at 500ºC were named PESPSiCr-01 and PESPSiCr-03 respectively. The basal spacings for the calcined clays were 9,56 Å (PESP-Na), 32 Å (PESPSiCr-01) and 15,38 Å ( PESPSiCr-03). The FTIR demonstrate the presence of bands attributed to stretching modes typical of this type of materials. The obtained results show that the clay PESPSiCr-01 calcined at 500ºC is completely deshydroxylated, whereas in the PESPSiCr-03 this process still does not take place. The batch adsorption process for Pb2+ and Pb2+ in the presence of Ca2+ was studied, in aqueous media and room temperature. The results show that the adsorption behavior of can be described by the Langmuir model. The qmax for Pb2+ reaches values of up to 139,1 mg Pb2+/g clay. The FTIR studies indicate that the clay sheet structure was not altered during the Pb2+ adsorption. The Eads determined from the model of Dubinin-Raduskevich, corresponds to 33,3 kJ/mol, which would indicate that the process of retention takes place basically by means of ionic exchange reactions at the surface sites located at the clay layered surface, the nanoparticles and the clay borders. The pillared clay presents pronounced affinity towards the Pb(II) adsorption still in the presence of Ca2+, with a factor of separation, α2, of 2,58.