Study of Chromium Removal by the Electrodialysis of Tannery and Metal-Finishing Effluents

Ruan C A Moura,Daniel A Bertuol,Carlos A Ferreira,Franco D R Amado

doi:10.1155/2012/179312

Abstract

The metal-finishing and tannery industries have been under strong pressure to replace their current wastewater treatment based on a physicochemical process. The electrodialysis process is becoming an interesting alternative for wastewater treatment. Electrodialysis is a membrane separation technique, in which ions are transported from one solution to another through ion-exchange membranes, using an electric field as the driving force. Blends of polystyrene and polyaniline were obtained in order to produce membranes for electrodialysis. The produced membranes were applied in the recovery of baths from the metal-finishing and tannery industries. The parameter for electrodialysis evaluation was the percentage of chromium extraction. The results obtained using these membranes were compared to those obtained with the commercial membrane Nafion 450.

Highlights

Over the past few decades, there has been increased concern for the preservation of water resources
Industrial activities have led to widespread heavy metal contamination of soils and natural waters
The purpose of this study is the investigation of the transport of some ions through synthesized membranes and a commercial one by electrodialysis

Summary

Introduction

Over the past few decades, there has been increased concern for the preservation of water resources. Among the various sources of water contamination, the electroplating industry stands out as one of the most important, because it generates a considerable volume of effluents containing high concentrations of metal ions and, often, high concentrations of organic matter [1]. Another aggravating factor is that the traditional process for the treatment of these effluents, not very efficient and in some cases totally inefficient, produces dangerous solid waste (electroplating sludge), which should, be disposed of in appropriate landfills. Chemical Oxygen Demand (COD), chlorides, sulfates, and chromium often do not reach the required limits [3]

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Conclusion