The development of new solvent-stable membranes in the past two decades has extended the applicability of nanofiltration for processing of natural extracts, obtained with organic solvents and their mixtures with water. The biologically active constituents of plants are traditionally isolated trough solid-liquid extraction and further evaporation of the obtained dilute liquid extracts. Significant reduction of the specific energy consumption while preserving product activity during the concentration or fractionation of liquid extracts from rosemary or spent coffee grounds, using nanofiltration, is demonstrated via experimental data and process simulations. Even though the concept has been proved at a laboratory scale, the application of nanofiltration for processing of natural extracts at production scale is rather scarce. The two main obstacles are the fact that until couple of years ago a reliable multiscale modeling framework and tools for simulation of these processes were not available and also that commercial membranes are prone to fouling from the target components of the plant materials. To address the first obstacle a complete modeling framework and tool, called “OSN Designer”, to support the nanofiltration process design has been developed. It was supposed to: cover all phenomena from the membrane nanoscale to the process macroscale; to require only limited number of experimental data at lab scale; to be compatible with existing process modeling environments, such as AspenONE, ChemCAD, etc. Using OSN Designer we investigated the effects at process level from drastically enhancing the membrane permeances by using different technics, to answer the question: will ultrafast membranes lead to ultrafast processes?

Discussed are current results on application of nanofiltration to fractionate hydrosols, residual waters, and hydroalcoholic biologically active extracts from spent plant material from the steam and hydrodistillation of essential oil plants. In terms of membrane materials needed, the topic is at the interface between OSN and aqueous nanofiltration.

Acknowledgements: This study is funded by the European Union - NextGenerationEU, through the National Recovery and Resilience Plan of the Republic of Bulgaria, project No BG-RRP-2.004-0002, "BiOrgaMCT" and the Bulgarian National Science Fund (contract KP-06-H37/14).