Membrane Crystallization and the crystallizer of the future

The opportunity to couple membrane processes and crystallization operations, in order to develop an efficient crystallization technology, has been proposed in the form of a membrane crystallizer (MCr). In this system, microporous hydrophobic membranes act as the physical support for contacting two liquid subsystems differing in temperature and/or composition, subjected to mass interchange in vapour phase. One of the main features of the MCr system is that the membrane does not act simply as support for the solvent evaporation, but also as a synthetic hydrophobic and porous surface able to activate heterogeneous nucleation starting at low supersaturation ratios, depending on the surface characteristics of the membrane. Thank to its advantages, as the high control in the crystallization processes even for the crystallization of organic materials, membrane crystallizers represent an additional option for realizing integrated, high efficient systems in the logic of the process intensification strategy, as e.g. in desalination, where a rational integration of this technology might determine substantial improvements in terms of water quality, product recovery factor, overall cost, environmental impact and brine disposal. This technique has furthermore gaining particular attention in the crystallization of bio molecules, such as proteins, and has being tested for enantioselective crystallization.