Abstract Summary
Inorganic acids are frequently used in the leaching process of end-of-life LIBs due to their low cost and high leaching efficiency. The use of HCl from MDI/polyurethanes production as a leaching medium greatly facilitates the separation of metals through the formation of chloro-metal complexes. Benzene and chlorobenzene, are some of the main contaminants obtained during the HCl recovery processes for LiCl production, from minerals or end-of-life cathode materials, posing a significant environmental and applicability concern. The primary objective of this study is to remove organic contaminants potentially present in the HCl stream from MDI production using fixed-bed column adsorption. Activated alumina and activated carbon were selected due to their chemical resistance. These materials were functionalized with different precursors to fine-tune their properties and enhance adsorption performance. Textural, morphological and chemical properties of the adsorbents were investigated employing scanning/transmission electron microscopy (SEM/TEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption isotherms at -196 ˚C. The preliminary results with the original alumina materials indicate that the material can effectively adsorb chlorobenzene from the HCl solution. Equilibrium was reached after 40 minutes, with an adsorption efficiency of 70%. The effects of flow rate, bed height, initial concentration, and contact time on adsorption performance were systematically evaluated. Breakthrough curves were analysed to determine equilibrium time and adsorption capacity. The results demonstrated that adsorption efficiency is significantly influenced by these parameters, providing valuable insights for optimizing fixed-bed column design and operation. This study contributes to the development of effective strategies for chlorobenzene removal. The authors acknowledge the financial support of the project Agenda NGS - New Generation Storage, with the reference n.º C644936001-00000045, co-funded by Component C5 – Capitalisation and Business Innovation under the Portuguese Resilience and Recovery Plan, through the NextGenerationEU Fund.
