Removal and recovery of Ag(CN)2- from synthetic electroplating baths by polymer inclusion membrane containing Aliquat 336 as a carrier

• Phase inversion technique for synthesis of PIMs based on Aliquat 336 was used.
• Morphological and chemical characterizations of PIMs were investigated.
• Application of PIMs for the removal and recovery of silver cyanide complex.
• Investigation of the membrane selectivity towards Ag(CN)2- and Zn(CN)42- anions.
• Lifetime and durability of PIM have been performed.

The current research deals with the first application of a polymer inclusion membrane (PIM) for the removal and recovery of silver cyanide complex from an aqueous solution. The effective PIM containing Aliquat 336 as the carrier, cellulose triacetate (CTA) as the base polymer, and Bis (2-ethylhexyl) sebacate (BEHS) as a plasticizer were prepared by phase inversion technique via solvent evaporation and characterized by different techniques. The effects of several factors on the transport efficiency including the nature and the concentration of the carrier, the type of base polymer and the plasticizer, initial concentration of the feed phase and the stripping phase nature have been studied. This study shows that the membrane composition affects considerably the Ag(CN)2- transport. The transport mechanism is implemented by an anionic exchange between the fixed site of the Aliquat 336 and the anionic species in the solution followed by their diffusion across the membrane. We revealed that the transport of Ag(CN)2- found to be enhanced by the increasing of initial complex concentration and the best silver cyanide removal was achieved when HCO3- is used as the stripping agent. Moreover, we found that PIM exhibited an important selectivity towards Ag(CN)2- than Zn(CN)42-. These promising results lead us to apply this technology for the removal of silver cyanide complex from real wastewater.

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