19-08-2014, 10:26 AM
The research investigation deals with use of an advanced extraction process, Liquid Emulsion Membrane (LEM) for the extraction and enrichment of cadmium (II) from an acidic leach stream. Ni-Cd batteries are commonly used in portable electronic devices. The spent Ni-Cd batteries discarded as a waste to environment results in soil and water pollution. Thus recovery of Cd is the part of E-waste management programme.
The research investigation deals with use of an advanced extraction process, Liquid Emulsion Membrane (LEM) for the extraction and enrichment of cadmium (II) from an acidic leach stream. Ni-Cd batteries are commonly used in portable electronic devices. The spent Ni-Cd batteries discarded as a waste to environment results in soil and water pollution. Thus recovery of Cd is the part of E-waste management programme.
The stoichiometry coefficient for the complexation of cadmium (II) with D2EHPA (di-2-ethylhexylphosphoric acid) was observed to be 2. Temperature effect was studied in the range of 20-45 oC, distribution coefficient was found to decrease with temperature. The liquid membrane made up of carrier D2EHPA, a surfactant (Monemul-80), water-repelling agent (cyclohexanone) and organic diluent (n-dodecane) was used. Methane sulfonic acid (MSA) was used as a stripping agent, forming w/o emulsion. Aqueous feed stream containing cadmium (II) was contacted with the above emulsion in a dynamic contactor. For emulsion preparation studies, experiments were designed using factorial design method. Using liquid emulsion membrane, enrichment of cadmium (II) as high as 16 times was observed.
A simple realistic process design engineer friendly rate based model for the LEM process was developed.