Sustainability of Spent Nickel-Based Electroplating Baths: An Innovative Valorisation Process

The plating industry is a high-pollutant sector because it consumes a significant amount of chemical compounds and produces a large volume of hazardous waste via the disposal of spent plating baths. Thus, the development of regeneration/purification routes to extend the lifetime of the plating baths may be a good opportunity to reduce both the environmental impact and the production costs of the plating industry. In this context, an innovative and in situ purification process, that uses magnetic nanoparticles (MNPs) to capture and remove contaminants and undesirable chemicals from the plating baths, extending their lifetime, was studied within the scope of the PureNano project. To support the process that has been developed, this work aimed to assess the sustainability of this recovery route and highlight its potential benefits. A comparative analysis was conducted between this novel route and conventional alternatives (i.e., underground disposal and incineration). To do so, the life cycle assessment (LCA) and life cycle costing (LCC) methodologies were used to evaluate the environmental impact and production costs, and an ecoefficiency analysis was performed to understand the trade-offs of each scenario. The results showed that MNPs were the main hotspot for the environmental impact and production costs. Overall, the purified plating baths may lead to lower environmental impacts (−98%) and processing costs (up to −95%) than other conventional alternatives. Regarding the ecoefficiency analysis, Scenario A (recovery route without MNPs recycling) and A-R (recovery route with MNPs valorisation) have a better economic/environmental impact relation than the conventional scenarios, i.e., incineration, and deposition in a landfill. However, Scenario A was the most ecoefficient scenario. In addition to this, further research is needed, namely, to search for other materials that may replace the most expensive and burdensome ones, and to investigate the use of renewable energy sources in MNPs production to improve their environmental and economic performances.