SURFER’Z: Understanding surface barriers in zeolites for molecular separations
The SURFER’Z project, coordinated by the LCS (CNRS, ENSICAEN, University of Caen Normandy), with Arnaud Travert as project coordinator, has been selected for funding by the French National Research Agency (ANR) as part of its 2026 Generic Call for Proposals.
SURFER’Z brings together the LCS and LIPhy (CNRS, Grenoble Alpes University) to study diffusion barriers at the external surfaces of zeolites.
The project is also conducted within the framework of the CARMEN Joint Research Laboratory, a collaborative research initiative dedicated to the characterization of materials for the energy transition. Both LCS and LIPhy are partners in CARMEN, which provides a common framework for combining advanced experimental characterization with multi-scale modeling.
Molecular separation: a major energy challenge
Molecular separation is an essential step in many chemical industry processes. Conventional techniques such as distillation rely on energy-intensive thermal operations. The development of alternative approaches based on adsorption therefore constitutes a major scientific and technological challenge.
Zeolites are particularly promising materials for such applications. Their molecular-sized pore networks, whose structure and properties can be precisely tuned, allow them to preferentially host specific molecules.
However, their performance does not depend solely on their adsorption capacity. The rates at which molecules enter the crystals, move through their pores, and exit also play a crucial role.
Understanding phenomena at zeolite surfaces
SURFER’Z focuses on diffusion barriers at the external surfaces of zeolite crystals. These transport resistances can slow down molecular exchanges between the surrounding medium and the microporous network.
They remain poorly understood, are difficult to observe directly, and can be hard to distinguish from diffusion phenomena occurring inside the crystals. Understanding them also requires linking multiple length and time scales, from molecular motion to the overall performance of a separation process.
The project pursues two complementary objectives:
- Understanding the origin of surface barriers and quantifying their importance.
- Establishing an experimentally validated predictive framework to determine when these barriers should be reduced or, conversely, could be exploited to improve separation performance.
The model system chosen for the project is the separation of short-chain alcohols containing two to four carbon atoms (C2 – C4). These molecules are of particular interest for biomass valorization and biofuel production.
A strategy combining experiments and modeling
The scientific program is structured around four main axes.
Material preparation and characterization
The teams will select zeolites and modify their external surfaces in a controlled manner to study the effects of surface chemistry, pore structure, and crystal size.
Molecular transport measurements
Operando infrared spectroscopy, pulsed field gradient nuclear magnetic resonance (PFG-NMR), and breakthrough experiments will be used to study adsorption, intracrystalline diffusion, and interfacial transport resistance.
Description of mechanisms at the molecular scale
Molecular simulations and theoretical models will provide a better understanding of alcohol adsorption and transport across zeolite interfaces.
Prediction of separation performance
Experimental and numerical data will be integrated to link microscopic mechanisms to the macroscopic behavior of the separation process.
A collaboration between LCS and LIPhy within CARMEN
SURFER’Z draws on the complementary expertise of two laboratories that are also partners within the CARMEN Joint Research Laboratory.
At the LCS in Caen, SURFER’Z brings together complementary expertise in spectroscopy, NMR, adsorption, molecular transport, as well as in the preparation and characterization of zeolites.
- Arnaud Travert , Professor at the University of Caen Normandy, brings his expertise in operando infrared spectroscopy, adsorption, and quantitative analysis of molecular transport phenomena.
- Cassandre Kouvatas , Associate Professor at the University of Caen Normandy, brings her expertise in NMR spectroscopy and experimental characterization of adsorption and molecular transport.
- Edwin Clatworthy , CNRS Researcher, brings his expertise in zeolite preparation, post-synthetic modification, physicochemical characterization, and breakthrough experiments.
At LIPhy in Grenoble, the project relies on the expertise of the Statistical Physics and Modeling (PSM) team in molecular simulation, statistical physics, and multi-scale modeling.
- Benoit Coasne, CNRS Research Director, brings his expertise in molecular-scale modeling of adsorption, confinement, and transport in nanoporous materials.
- Simon Gravelle, CNRS Researcher, brings his expertise in molecular simulation and multi-scale modeling of transport in confined systems.
This complementarity is at the heart of the CARMEN approach: linking the in situ/operando characterization of transport in microporous solids to molecular and mesoscopic modeling to obtain a multi-scale description of material behavior.
Two complementary PhD projects
Two PhD students will be recruited as part of SURFER’Z.
The PhD project at LCS will focus on the experimental side of the project: preparation and post-synthetic modification of zeolites, physicochemical characterization, operando IR spectroscopy, PFG-NMR measurements, and breakthrough experiments.
The PhD project at LIPhy will focus on molecular simulations and theoretical modeling of adsorption and transport across zeolite interfaces, as well as the transfer of information obtained at the molecular scale to macroscopic models.
Together, the two PhD projects will provide complementary experimental and theoretical descriptions of surface diffusion barriers.
Towards a predictive understanding of surface barriers
SURFER’Z aims to make surface barriers measurable, predictable, and potentially useful for molecular separation.
By establishing quantitative relationships between surface chemistry, crystal size, porosity, and molecular transport, the project seeks to provide the scientific foundations necessary to improve the design of materials and adsorption-based separation processes.
Ultimately, SURFER’Z aims to establish a fundamental and predictive understanding of transport phenomena at the interfaces of nanoporous materials, while proposing new concepts for the design of molecular separation processes.
Partners
