Crystallization by selective evaporation using membrane pervaporation: Application to l-glutamic acid to control polymorphism

• Published in: Journal of membrane science 2023-02, Vol.668, p.121256, Article 121256
• Main Authors: Khellaf, Maya, Huang, Xiaoqian, Valour, Jean-Pierre, Mangin, Denis, Charcosset, Catherine, Chabanon, Elodie
• Format: Article
• Language: English
• Subjects: Chemical and Process Engineering; Chemical engineering; Chemical Sciences; Engineering Sciences; HybSi® membrane; l-glutamic acid; Membrane crystallization process; Pervaporation; Polymorphism control
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2022.121256

Crystallization is an important unit operation in process industries, driven by supersaturation, i.e. the solute concentration difference between solution and equilibrium. Hence, to finely control the product qualities, controlling mass and/or heat transfer is crucial. Membrane pervaporation, based on a selective evaporation technique, appears as a process able to limit phase transition and control polymorphism. In this work, a semi-continuous system is developed for the crystallization of l-glutamic acid, which has two polymorphic forms. Hydrophilic HybSi® membranes are chosen. The influence of different operating parameters on process performance in terms of solvent separation, solute crystallization and control of polymorphism is investigated. Results validate the proof of concept and highlight the preferential crystallization of a polymorphic form over the other. Hence, the α-form is usually favoured except when the β-form is seeded, or at high temperature. Temperature appears as the parameter influencing mostly the membrane selectivity and the polymorph generated. However, concentration polarization and fouling, due to the deposit of l-glutamic acid crystals on the membrane surface, are reported and decrease the process performance. Both phenomena are caused by a high local supersaturation close to the membrane surface in addition to a local cooling due to the water evaporation during pervaporation. [Display omitted] •Selective evaporation of water by pervaporation for l‐glutamic acid crystallization.•Pervaporation/crystallization process on a lab‐scale pilot using membrane HybSi®.•Control of polymorphism through appropriate choice of operating conditions.•Highlight concentration polarization and fouling responsible of performance decrease.