Towards Regeneration and Reuse of Ionic Liquids in Electroplating

Towards Regeneration and Reuse of Ionic Liquids in Electroplating 

However, it can be assumed for most electrochemical applications of ionic liquids, especially for electroplating, that suitable regeneration procedures can be found. This is first, because transfer of several regeneration options that have been established for aqueous solutions should be possible, allowing regeneration and reuse of ionic liquid based electrolytes. Secondly, for purification of fiesh ionic liquids on the laboratory scale a number of methods, such as distillation, recrystallization, extraction, membrane filtration, batch adsorption and semi-continuous adsorption in a chromatography column, have already been tested. The recovery of ionic liquids from rinse or washing water, e.g. by nanofiltration, can also be an important issue. 

For electroplating purposes ionic liquids show several attractive properties, such as large electrochemical windows, specific solvent characteristics and extremely low vapor pressures compared to ordinary solvents. When used as base electrolytes in electroplating, ionic liquids can allow new processes that are impossible in conventional electroplating where the main solvent used is water. 

In general, recyclability is crucial for the design of sustainable chemical processes [83]. The aspect that should be elaborated here is the possibility of regeneration and reuse of the ionic liquid, depending on the type of impurity and the sensitivity of the specific application towards contamination. 

Despite the huge number of publications dealing with the application of ionic liquids, there are only a couple that include reuse aspects. To the best of our knowledge, there is none that deals with regeneration of spent ionic liquid based electrolytes. The intention of this contribution is to bridge this gap and suggest potential concepts for ionic liquid regeneration. 

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