Minimizing the environmental impact of the regeneration process of an ion exchange bed charged with transition metals

• Published in: Separation and purification technology Vol. 49; no. 2; pp. 167 - 173
• Main Authors: Valverde, José L., De Lucas, Antonio, Carmona, Manuel, Pérez, Juan P., González, Marcela, Rodríguez, Juan F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-04-2006; Elsevier Science
• Subjects: Applied sciences; Chemical engineering; Diffusion; Exact sciences and technology; Fixed resin bed; Heat and mass transfer. Packings, plates; Ion exchange; Kinetics; Mass transfer; Nernst–Planck; Regeneration; Nernst–Planck; Regeneration; Fixed resin bed; Kinetics; Ion exchange; Diffusion; Mass transfer; Elution; Nemst-Planck; Final waste; Modeling; Transport process; Mass action law; Environment impact; Affinity; Mathematical model; Fixed bed
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2005.09.009

A transport mathematical model to describe the performance of ion exchange processes in fixed beds, to use the regeneration curves as a tool to optimize the regeneration process was developed. The model is based on both the Nernst–Planck equation and the mass action law. This model allowed to obtain the optimum amount of regenerant agent to be used, regardless the system considered. Therefore, it would be possible to minimize the final waste volume and maximize the recovered bed capacity without any additional consumption of regenerant agent.
The results obtained allowed to conclude that the sodium chloride is better regenerant agent than chlorhydric acid for strong acid resins, because it requires a lower amount of equivalents to reach the same regeneration level and is cheaper. Finally, the concentration of regenerant agent required for copper elution is less than that required for the other ions (Cd
2+ and Zn
2+). These results were found to agree with the affinity of the resin.