Selective separation of chromium (III) from electroplating effluents by ion-exchange processes

This work reviews the application of the ion-exchange technology to treat industrial effluents containing heavy metals and presents results on the uptake of Cr (III) from aqueous solutions using the polyfunctional chelating exchange resin Diphonix. Some industrial samples of effluent collected in an electroplating industry were characterized in what respects metals, total suspended and dissolved solids (TSS, TDS), chemical oxygen demand (COD) and pH. In order to evaluate the sorption capacity of the resin, some batch equilibrium experiments were carried out. The effects of temperature and the presence of acid nitric in solution on the ion-exchange equilibrium were studied, and it was observed that the sorption capacity of the resin is affected by both variables. Moreover, saturation experiments in column were also performed in order to determine the dynamic behaviour of the process. The results suggest that the resin tested offers a good performance towards the Cr(III) removal and can be easily regenerated with a mixture of NaOH and H2O2.