Elimination of Cu(II) from Aqueous Solutions by Liquid-liquid Extraction. Test of Sodium Diethyldithiocarbamate (SDDT) as an Extracting Agent

Abstract

The presence of heavy metals in industrial wastewaters, can be an important source of pollution, and may be a severe health hazard, due to their toxicity and to the fact that they are not amenable to biological degradation. Copper is a typical environmental heavy metal pollutant. It is considered in the present study since at high concentration exceeding certain limits, it may cause severe mucosal and a central nervous irritations, necrotic changes in the liver and kidney, etc. So it is necessary to treat wastewaters containing this heavy metal to reduce its concentration before discharge. Different and traditional methods for the removal and recovery of copper from industrial waste streams do exist each having its lacks and shortcomings. One can cite precipitation, ion exchange, electrolysis, adsorption on activated carbon and liquid-liquid extraction which is used in the present work. The main objective of the present experimental work is the determination of the best conditions for the extraction of Cu(II) ions from aqueous solutions, using sodium diethyldithiocarbamate (SDDT) as the extracting agent and different organic solvents, such as chloroform and dichloromethane, as diluents. The analysis of the aqueous phase after separation was performed by means of an atomic absorption spectrophotometer. The obtained experimental results showed that high copper extraction yields are achieved for an added extracting agent mass greater than 7.5 mg, fixing the aqueous phase pH at 9. The results showed that the extraction process was more efficient when using dichloromethane rather than chloroform, although this latter is more used in practice.