Binary ion exchange of metal ions in Y and X zeolites

The ion exchange of Na for Cr/K, Cr/Mg and Cr/Ca in Y and X zeolites was studied using breakthrough curves. It was observed that Cr3+ ions were able to remove some competitive ions that had already been exchanged at the zeolitic sites, producing a sequential ion exchange. Some mass transfer parameters such as length of unused bed, overall mass transfer coefficient, operational ratio and dimensionless variance were studied. Chromium uptake was influenced much more by the competing ion in the NaX zeolite columns. The dimensionless variance indicated that Cr/K solution produced a greater axial dispersion than the Cr/Mg and Cr/Ca systems, probably due to some interaction between Cr3+ and K+ ions. The order of dynamic selectivity, provided by the cation uptake, was Cr3+ > Ca2+, Cr3+ > Mg2+ and Cr3+ > K+ for NaY zeolite and Ca2+ ~Cr3+, Mg2+ > Cr3+ and Cr3+ > K+ for NaX zeolite. Due to the more favorable mass transfer parameters and higher affinity for Cr3+, it was concluded that NaY zeolite was more efficient at chromium uptake in competitive systems

Zinc Adsorption In Bentonite Clay: Influence Of Ph And Initial Concentration [adsorção De Zinco Em Argila Bentonita: Influência Do Ph, Quantidade De Adsorvente E Concentração Inicial]

This paper evaluated the adsorption capacity of zinc by Bofe bentonite clay. Bofe clay was subjected to a thermal treatment for optimizing its adsorption capacity. The kinetic equilibrium of the process was studied in a finite bath system and experiments were performed by varying pH, the amount of adsorbent and initial concentration of the metal. The Langmuir and Freundlich models were used for the analysis of adsorption equilibrium. The physicochemical characterization of clay, before and after the adsorption process, included the techniques of scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and N2 physisorption. The calcined Bofe clay is able to remove zinc from synthetic wastewater. Langmuir model provided the best fit for sorption isotherms with a maximum amount of metal adsorbed of 4.95 mg of metal g-1 of calcined clay. The adsorption was strongly influenced by the initial conditions and modifies the physicochemical characteristics of the clay.352325332Abollino, O., Giacomino, A., Malandrino, M., Mentasti, E., Interaction of metal íons with montmorillonite and vermiculite (2008) Applied Clay Science, 38 (3-4), pp. 227-236Amorim, L.V., Viana, J.D., Farias, K.V., Barbosa, M.I.R., Ferreira, H.C., Estudos comparativos entre variedades de argilas bentoníticas de Boa Vista, Paraíba (2006) Revista Matéria, 11 (1), pp. 30-40Arias, F., Sen, T.K., Removal of zinc metal ion (Zn2+) from its aqueous solution by kaolin clay mineral: A kinetic and equilibrium study (2009) Colloids and Surfaces A: Physicochemical and Engineering Aspects, 348 (1), pp. 100-108Bhattacharyya, K.G., Gupta, S.S., Adsorptive accumulation of Cd(II), Co(II), Cu(II), Pb(II), and Ni(II) from water on montmorillonite: Influence of acid activation (2007) Journal of Colloid and Interface Science, 310 (2), pp. 411-424Bhattacharyya, K.G., Gupta, S.S., Adsorption of a few heavy metals on natural and modified kaolinite and montmorillonite: A review (2008) Advances in Colloid and Interface Science, 140 (2), pp. 114-131Bojemueller, E., Nennemann, A., Lagaly, G., Enhanced pesticide adsorption by thermally modified bentonites (2001) Applied Clay Science, 18 (1-6), pp. 277-284Chen, W.J., Hsiao, L.C., Chen, K.K.Y., Metal desorption from copper(II)/nickel(II)-spiked kaolin as a soil component using plant-derived saponin biosurfactant (2008) Process Biochemistry, 43 (5), pp. 488-498Fagundes-Klen, M.R., Veit, M.T., Silva, E.A., Bergamasco, R., Martins, T.D., Canevesi, R.L.S., Modelagem do efeito do pH na biossorção de metais pela alga marinha Sargassum filipendula (2011) Acta Scientiarum. Technology, 33 (4), pp. 439-446Ghorbel-Abid, I., Galai, K., Trabelsi-Ayadi, M., Retention of chromium (III) and cadmium (II) from aqueous solution by illitic Clay as a low-cost adsorbent (2010) Desalination, 256 (1-3), pp. 190-195Jiang, M.-Q., Jin, X.-Q., Chen, Z.-L., Adsorption of Pb (II), Cd (II), Ni (II) and Cu (II) onto natural kaolinite clay (2010) Desalination, 252 (1-3), pp. 33-39Kubilay, S., Gurkan, R., Savran, A., Sahan, T., Removal of Cu (II) and Zn (II) ions aqueous solutions by adsorption onto natural bentonite (2007) Adsorption, 13 (13), pp. 41-51Silva, M.L.P., Rodrigues, M.G.F., Silva, M.G.C., Remoção de cádmio a partir da argila de Toritama (estado de Pernambuco) ativada termicamente em sistema de banho finito (2009) Cerâmica, 55 (1), pp. 11-17Souza Santos, P., (1992) Ciência e tecnologia de argilas, , São Paulo: Editora Edgard Blücher LtdaStathi, P., Litina, K., Gournis, D., Giannopoulos, T.S., Deligiannakis, Y., Physicochemical study of novel organoclays as heavy metal ion adsorbents for environmental remediation (2007) Journal of Colloid and Interface Science, 316 (2), pp. 298-309Stumm, W., (1992) Chemistry of the solid-water interface, , New York: John Wiley and SonsTito, G.A., Chaves, L.H.G., Ribeiro, S., Souza, R.S., Isotermas de adsorção de cobre por bentonita (2008) Revista Caatinga, 21 (3), pp. 16-21Treybal, R.E., (1980) Mass transfert operations, , New York: McGraw HillVieira, M.G.A., Almeida Neto, A.F., Gimenes, M.L., Silva, M.G.C., Sorption kinetics and equilibrium for the removal of nickel ions from aqueous phase on calcined Bofe bentonite clay (2010) Journal of Hazardous Materials, 177 (1-3), pp. 362-371Yukselen, Y., Asce, M., Kaya, A., Comparison of methods for measuring the surface area of soils. Technical note (2006) Journal of Geotechnical and Geoenvironmental Engineering, 132 (1-3), pp. 931-93