The aim of this work was to develop a quantitative description of the ion exchange equilibria of arsenic on a strong anionic resin, in the presence of nitrates and sulphates. First, the ion exchange equilibrium data of As(V) and NO3− on a strong anionic resin in chloride form were obtained and described with a model based on the mass action law. Namely, assuming ideal behaviour for both solution and resin phase, the thermodynamic constant of the As(V)/Cl− and NO3−/Cl− ion exchange equilibria were estimated by fitting of experimental data. Then, these equilibrium constants were used to predict the ion exchange behaviour of the ternary system As(V)/NO3−/Cl−, providing a rather good agreement with experimental results. The ion exchange equilibria involving sulphate ions were also studied, showing a very high affinity to the resin phase. This behaviour did not allow a quantitative robust modelling of the equilibrium pattern. The results discussed in this paper represent a first step toward the development of a comprehensive modelling of the ion exchange process for the removal of As(V) from surface and groundwater in the presence of competitive, naturally occurring anions.
Ion exchange equilibria of arsenic in the presence of high sulphate and nitrate concentrations
R. Baciocchi, A. Chiavola, R. Gavasci; Ion exchange equilibria of arsenic in the presence of high sulphate and nitrate concentrations. Water Science and Technology: Water Supply 1 December 2005; 5 (5): 67–74. doi: https://doi.org/10.2166/ws.2005.0040
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