Adsorption of pollutant ions from residual aqueous solutions onto nano-structured calcium silicate

• F VALENZUELA ^[1] ; C BASUALTO ^[1] ; J SAPAG ^[1] ; V IDE ^[1] ; N LUIS ^[1] ; N NARVAÉZ ^[1] ; S YAÑEZ ^[1] ; T BORRMANN ^[2]
  1. [1] Universidad de Chile

     Universidad de Chile

     Santiago, Chile

     
  2. [2] Victoria University of Wellington

     Victoria University of Wellington

     Nueva Zelanda

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 58, Nº. 2, 2013, págs. 1744-1749
• Idioma: inglés
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• Resumen

  • The sorption of contaminant ions existing in residual aqueous solutions onto nano-structured calcium silicate has been studied. The sorbent was prepared by chemical reaction between a soluble solution of sodium silicate and calcium hydroxide. X-ray diffraction analysis showed the amorphous character of the obtained calcium silicate, although patterns associated to wollastonite, CaSiO3, and larnyta-syn, Ca2SiO4 were detected. The particle mean size was approximate 0.5 to 1.0 ìçé having an average BET surface area of 333.0 m²/g and a mean pore diameter variable between 15.8-23.6 nm. The nano-structured calcium silicates were contacted with industrial residual aqueous solutions containing, among others, Cu(II), Zn(II), Cd(II) and the anions PO4(3-), SO4' and CrO4', being copper (II) and phosphate the ions that were most easily and quantitatively adsorbed. The results of equilibrium experiments showed that the Redlich-Peterson adsorption isotherm model explained the experimental results for some metal ions.The experimental kinetics followed a pseudo-second-order kinetics model for Cu(II) and Zn(II) sorption.