Influence of High Chloride Concentration on pH Control in Hydroxide Precipitation of Heavy Metals

Marcin Stec,Barbara Jagustyn,Krzysztof Słowik,Marek Ściążko,Tomasz Iluk

doi:10.1007/s40831-020-00270-x

Marcin Stec, Barbara Jagustyn + Show 3 more

Open Access

https://doi.org/10.1007/s40831-020-00270-x

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Abstract

Removal of zinc and cadmium from highly saline solutions by hydroxide precipitation is discussed. Experimental solubilities of zinc and cadmium in highly saline solutions were compared to modeled results obtained using Pitzer’s approach. An amphoteric character of zinc and cadmium and an influence of chloride ion on the concentration of dissolved metals were investigated. In order to avoid errors linked to pH measurements in concentrated aqueous solutions, the method of calibration of glass pH electrodes was developed and evaluated. The method uses easily prepared buffers whose pHs were determined with the Pitzer ion-interaction approach. The presented investigations address two issues of high significance in industrial wastewater treatment, namely: precise pH measurements and rigorous modeling of highly saline wastewaters. The results can be implemented in the treatment of hydrometallurgical wastewaters such as zinc refinery wastewater. Additionally, an implementation of the presented investigations is not limited to wastewater treatment but can easily be extended to other high-chloride metallurgical processes wherein the pH measurements in highly saline streams are required.Graphical

Highlights

The continuous progress of industrialization significantly affects the environment by contamination with heavy metals [1, 2]
Despite tremendous work done to optimize precipitation processes, there are still several challenges present. One such challenge is that heavy metals precipitation forms highly saline wastewaters
The aim of this study is to introduce a possibility of using Pitzer’s approach to estimate the composition of simple buffers of high ionic strength and to model the precipitation of heavy metals from high ionic strength solutions

Summary

Introduction

The continuous progress of industrialization significantly affects the environment by contamination with heavy metals [1, 2]. Harmful effects of heavy metals contamination against living organisms are well known and well documented. To address this significant aspect, several methods of removal of heavy metals from wastewater have been developed but precipitation of metals remains the most popular technique on an industrial scale. Despite tremendous work done to optimize precipitation processes, there are still several challenges present. One such challenge is that heavy metals precipitation forms highly saline wastewaters

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