variavel0=<b>M. A. S. D. BARROS</b> - angelica@deq.uem.br UEM
<b>A. S. ZOLA</b> -  UEM
<b>P. A. ARROYO</b> -  UEM
<b>C. R. G. TAVARES</b> -  UEM
<b>E. F. SOUSA-AGUIAR</b> -  UFRJ
<b>Abstract.</b> In this paper it was analyzed the chromium ion exchange in NaA zeolite in the presence of cations Mg2+, Ca2+ and K+. Multicomponent ion exchange were studied in two groups: binary solutions (Cr/Mg, Cr/Ca and Cr/K) and ternary solutions (Cr/Mg/Ca, Cr/Mg/K and Cr/Ca/K). Mass transfer and operating parameters were obtained such as length of unused bed, overall mass transfer coefficient and dimensionless variance. It was concluded that the presence of the competing ions alters the exchange behavior and at least a binary solution must be considered in designing a packed bed to treat industrial wastewater. The presence of Ca2+ and Mg2+ ions decrease chromium uptake in a higher extension than the presence of K+ ions.
<b>Keywords.</b> zeolite, NaA, dynamic ion exchange, chromium.