Removal of heavy metals from Water Rinsing of Plating Baths by Electrodialysis

During the chromic plating of parts, the baths become more and more poor in chromic acid and rich in metallic impurities such as Cu2+, Zn2+, Fe3+ and Cr3+ which makes the bath useless. Also, the water used to rinse parts contains chromic acid and metallic impurities. As it is known that chromic acid is relatively expensive and very toxic, so its recovery has double interest: economic and environmental. Its reuse is possible after removal of metallic impurities. In this work, we studied the possibility of metallic impurities elimination from the chromic acid. The influence of the current density and the circulating solution flow rate on the process efficiency has been studied. The elimination rates obtained in the presence of ion exchange textile are superior to those obtained in the absence of textile. The analysis of the results showed that for the three metallic impurities studied (Cu2+, Fe3+ and Zn2+), the purification rate increases versus the applied current density and solution flow rate. The importance of the elimination of the three metal cations is as the following order: Cu2+ >Zn2+ >Fe3+

Removal of heavy metals from Water Rinsing of Plating Baths by Electrodialysis

During the chromic plating of parts, the baths become more and more poor in chromic acid and rich in metallic impurities such as Cu2+, Zn2+, Fe3+ and Cr3+ which makes the bath useless. Also, the water used to rinse parts contains chromic acid and metallic impurities. As it is known that chromic acid is relatively expensive and very toxic, so its recovery has double interest: economic and environmental. Its reuse is possible after removal of metallic impurities. In this work, we studied the possibility of metallic impurities elimination from the chromic acid. The influence of the current density and the circulating solution flow rate on the process efficiency has been studied. The elimination rates obtained in the presence of ion exchange textile are superior to those obtained in the absence of textile. The analysis of the results showed that for the three metallic impurities studied (Cu2+, Fe3+ and Zn2+), the purification rate increases versus the applied current density and solution flow rate. The importance of the elimination of the three metal cations is as the following order: Cu2+ >Zn2+ >Fe3+

Phosphate ore washing by Na2EDTA for cadmium removal: Optimization of the operating conditions

This paper discusses the extraction of cadmium from phosphate ore by the washing method. Various parameters were investigated for the cadmium extraction from phosphate ore. The results from extraction tests showed that cadmium extraction depends on the nature and concentration of the extracting agent, the liquid/phosphate ore ratio, the temperature and the solution pH. The effi ciency of the nine extracting agents for removing cadmium from phosphate ore was found to be in the order: Na2EDTA > citric acid > tartric acid > ammonium citrate > calcium chloride > ammonium acetate > ammonium chloride > oxalic acid > ammonium hydroxide. In this study cadmium extraction kinetics was best described by the product layer diffusion control model

Photocatalytically-assisted electrooxidation of herbicide fenuron using a new bifunctional electrode PbO2/SnO2-Sb2O3/Ti//Ti/TiO2.

International audienc

Photocatalytically-assisted electrooxidation of herbicide fenuron using a new bifunctional electrode PbO2/SnO2-Sb2O3/Ti//Ti/TiO2.

International audienc