Nickel uptake from a wastewater stream produced in a metal finishing industry by combination of ion-exchange and precipitation methods

Abstract

In this study, ion-exchange process was applied individually as well as in combination with the precipitation process for the removal of nickel in a wastewater stream originating from a rinse bath of aluminum parts after sealing, in the anodizing process of a metal surface treatment industry. The results showed that the individual application of the ion-exchange led to removal of nickel up to 74.8% while the metal uptake rates were higher in the first stage of the process. Higher reduction in nickel concentrations was obtained by using the combination of ion-exchange and precipitation processes (from 94.2 to 98.3%). The optimum conditions for the development of the process include application of the precipitation by wastewater pH adjustment in 10.5 followed by ion-exchange process, using pretreated clinoptilolite for a time period which does not exceed 2 h.