# Progress in Electrodeposition of Zinc and Zinc Nickel Alloys Using Ionic Liquids
## 7 Industrial Scope  
If ILs are to be employed for electrodeposition on a larger (industrial) scale, the effect of impurities either emanating as a byproduct from the synthesis of ILs or traces of water in the form of drag-out needs to be considered. Adopting the ionic liquid-based system on an industrial scale for electroplating applications requires suitable recycling and disposal methods [75; 76]. Though the non-volatile nature of the ILs makes them attractive for electroplating applications, there are certain issues associated with them when employed at industrial scale. In addition, the high viscosity of ILs affects the mass transportation of the species, which leads to the low mobility and diffusion coefficient of metal ions. Therefore, the design and preparation of ILs with the desired physical and chemical properties such as viscosity, stability, conductivity, and composition require a significant effort. Furthermore, ionic liquids cannot be easily purified by conventional methods such as distillation. An additional issue that might arise during the scale up is the heat capacity of the ionic liquids. On the basis of the work reported by [PERSON] et al. [77], the heat capacity values of imidazolium and pyridinium salts were in the range of 300 to 600 J K\({}^{-1}\)mol\({}^{-1}\), indicating that that the ILs might actually have to be cooled rather than heated. Another disadvantage with the use of some ionic liquids is that they may suffer from ohmic heating, owing to their low electrical conductivity during electroplating. Research on ILs the field of electroplating technology has expanded significantly over the past decade. Once the technical performance of an ionic liquid is fully demonstrated, it becomes obvious that, at a certain point, the price determines the final commercial success of a product as it decides the economic feasibility of the IL-based system or process. At that point, a good marketing strategy is to explain that the higher costs of using ILs also bring added value. Any available cost analysis for a given plating system is usually based upon academic research, because of the trade secrets and commercial sensitivity involved in the proprietary electrolytes developed by industries and commercial organisations. Thus, the cost discussions on Zn and Zn-Ni alloys are based upon the information available in the literature on non-commercial electrolytes used by various science and engineering research laboratories. It is, however, worth noting that most of the academic work is primarily initiated after conducting a survey of literature and discussions with commercial electrolaters. Figure 2 shows the cost comparison of ionic liquid-based systems against aqueous electrolytes considering an industrial scale of 100 L make up. The cost is calculated considering the quantity of individual constituent components required for the IL-based system from the references [6; 43; 50; 72; 78] and the value of each constituent is calculated based on the Sigma-Aldrich and Merck pricing. From Figure 2, ILs seem uneconomical compared with traditional aqueous and organic solvents owing to their high cost, which greatly prohibited their applicability on a large scale. However, it is worth noting that recycling the drag out solution (process solution transferring into subsequent rinse water tanks) shall enhance the life of the ionic liquid-based plating solution, saving cost while eliminating the environmental impact of the process due to the drag out (reducing the source of pollutants). The plating solution and the rinse water can be recycled many times without affecting the quality of the coatings formed, as long as the contamination level is closely monitored. After performing Zn and Zn-Ni alloy plating using ionic liquid-based systems, a film of the bath solution will remain on the parts, the rack, or barrel and remain in cavities and gaps owing to their high viscosities [79].