Playing with Pore Size for Enhanced Alkane/Alkene Separations

Organisation/Company

MADIREL

Research Field

Chemistry
Engineering » Process engineering

Researcher Profile

Recognised Researcher (R2)
Leading Researcher (R4)
First Stage Researcher (R1)
Established Researcher (R3)

Country

France

Application Deadline

29 Apr 2024 – 22:00 (UTC)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

1 Sep 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

Context. The total process cost of chemical separations lies around 10-15% of the world energy use. Amongst these, the separation of alkane and alkenes is one of the most challenging. The current separation of propane and propylene, ethane and ethylene mixtures are carried out at extremely low temperatures (-70 °C or -160 °C). Since the global production of propane and propylene exceeds 200 million tons, this represents a huge energy demand. Any process operating under mild conditions, would have a huge impact. This thesis topic is focussed on adsorption-based separations using microporous materials as an alternative.

Research objectives. The goal of the thesis is to explore the use of microporous materials for alkane/alkene separations. Two routes will be explored: (i) leveraging the unique selective properties of small pore zeolites and (ii) the use of mechanical pressure to regenerate flexible adsorbents.

On the one hand, cage-and-window type zeolites (CHA, LTA, …) possess pore sizes comparable to the molecules to be separated. The adsorption of alkanes in such zeolites leads to entropic effects: from a certain chain length onwards, molecules have to ‘coil’ inside the structure. These entropic effects have been demonstrated at low adsorbed amounts1 and by molecular simulation.2 The objective of this part of the research is to better understand the mechanisms behind such effects. Unique equipment available at the MADIREL allows the simultaneous measurement of adsorption isotherms coupled to microcalorimetry. The technique will allow us to gain insight into adsorption energetics over the full range of the isotherm. Next, experimental work in dynamic conditions, supported by process modelling, will allow to gain insight into how these effects extrapolate to real separation applications.

On the other hand, unique equipment has been developed in the MADIREL laboratory, which allows to measure the adsorption of gasses on materials under mechanical constraints. In a 2020 Nature Comms. paper, the group has shown that the mesoporous MIL-53 Metal Organic Framework can be contracted under mechanical pressure, allowing to finetune the pore size of MIL-53 for CO2 / CH4 separation and CO2 / N2 separation.3 The use of mechanical pressure to finetune the pore shape and pore opening of other breathing MOFs will be investigated, specifically for hydrocarbon separations. An exploratory path will be investigated by the adjustment of the in-house developed equipment to allow measurements in dynamic mode, allowing the full exploration of this method to control separation selectivity and regenerate porous materials.

Candidature. The candidate should have a Master of Science in physical chemistry or chemical engineering. He/she should have a solid background with good grades.

Laboratory. The investigation of adsorption mechanisms in microporous materials is one of the key topics within the MADIREL laboratory. The candidate will be trained in a wide variety of characterisation techniques available in the lab: N2 adsorption at 77K, Hg intrusion, microcalorimetry, …

Funding. The offer does not consist of a fully funded position, but we are looking for a candidate to apply of the internal auditions of the Doctoral School ED250 at Aix-Marseille University. Together with the candidate, we will prepare a written application (deadline 13/05/2024) and oral auditions (30/05/2024 and 31/05/2024. The position opens in October 2024.

Contact details. The thesis will be co-guided by Dr. Benjamin Claessens and Dr. I. Beurroies of Aix-Marseille University. Prospective candidates are requested to send a CV, motivation letter and a copy of their final year notes to benjamin.claessens(at)univ-amu.fr or isabelle.beurroies(at)univ-amu.fr. Two contacts are requested who can be contacted as a reference.

References.

(1)          Denayer, J. F. M.; Devriese, L. I.; Couck, S.; Martens, J.; Singh, R.; Webley, P. A.; Baron, G. V. Cage and Window Effects in the Adsorption of N-Alkanes on Chabazite and SAPO-34. J. Phys. Chem. C 2008, 112 (42), 16593–16599. https://doi.org/10.1021/jp804349v .

(2)          Krishna, R.; Smit, B.; Calero, S. Entropy Effects during Sorption of Alkanes in Zeolites. Chem. Soc. Rev. 2002, 31 (3), 185–194. https://doi.org/10.1039/b101267n .

(3)          Chanut, N.; Ghoufi, A.; Coulet, M. V.; Bourrelly, S.; Kuchta, B.; Maurin, G.; Llewellyn, P. L. Tailoring the Separation Properties of Flexible Metal-Organic Frameworks Using Mechanical Pressure. Nat. Commun. 2020, 11 (1), 1–7. https://doi.org/10.1038/s41467-020-15036-y .

Funding category: Contrat doctoral
We are looking for a candidate to propose for auditions for the Ecole Dectorale
PHD Country: France

Requirements
Specific Requirements

We are looking for a candidate with a background in chemistry, physical chemistry or chemical engineering. The candidate will have to perform auditions for the ED to be accepted for the PhD. The candidate will be strongly coached for these auditions. Intereseted candidates should send a CV, motivation letter and references of 2 previous supervisors. 

Additional Information
Work Location(s)

Number of offers available

1

Company/Institute

MADIREL

Country

France

City

Marseille

Geofield

Where to apply

Website

https://www.abg.asso.fr/fr/candidatOffres/show/id_offre/121628

STATUS: EXPIRED