PhD offer University of Montpellier: Coupling nanofiltration and highly effective and stable membranes for electrooxidation of persistent pollutants in water

7 Mar 2024
Job Information

Organisation/Company

University of Montpellier

Research Field

Chemistry

Researcher Profile

First Stage Researcher (R1)

Country

France

Application Deadline

21 Apr 2024 - 08:00 (Europe/Paris)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

9 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

What is the ExposUM Doctoral Nexus?

The Doctoral Nexus proposed by the ExposUM Institute are networks of 3 to 4 PhD students from different disciplines and affiliated to at least two different research units. Compared with a traditional PhD, taking part in a Doctoral Nexus will encourage the ability to work in a team and to design projects in a transdisciplinary way while deepening one's own field of expertise. A specific teaching programme will be offered and the doctoral students concerned will also have the opportunity to organise a seminar within the Nexus network. Theses are funded from the outset for 4 years, including the PhD student's salary and an environmental allowance.

PhD project: Coupling nanofiltration and highly effective and stable membranes for electrooxidation of persistent pollutants in water

Context

The widespread infiltration of PFAS into our drinking water systems poses a significant challenge, spurring the need for advanced water treatment solutions. Membrane filtration, in particular nanofiltration, is able removing PFAS from water but generates concentrates that need to be handled [1]. Electrochemical-based advanced oxidation processes (AOPs) play a pivotal role in addressing this issue, offering the unique capability to break down a variety of recalcitrant organic substances. These processes generate reactive species directly within the water, thereby reducing reliance on external chemical agents and enabling the integration with renewable energy sources for operation. They hold great promise for effectively purifying drinking water from PFAS. Current research aims to overcome the existing drawbacks related to the creation of harmful by-products and limited efficiency due to the low concentrations typically found in drinking water [2]. Additionally, advancements are being pursued to enhance the cost-effectiveness and durability of electrocatalysts essential for the scalability of such treatment methods in potable water applications

Objective and methods

The global objective of this thesis is to study the coupling of nanofiltration and electrochemicalbased advanced oxidation to remove PFAS (PFOA and PFOS) and produce safe drinking water. The novelty of the project is based on the development of porous 3D Perovskite oxides membrane (CaCu3Ti4O12 (CCTO)) as novel electrocatalysts that aim at providing a suitable trade-off between reactivity and stability. The 3D structure will allow for implementation of continuous flow-through reactors for improving mass transport conditions owing to fast radial diffusion within pores combined with convection-enhanced mass transport during filtration. Our objective is organized around four tasks.

Task 1. Characterization of the efficiency of PFAS removing using nanofiltration membranes In this task, we aim to assess the efficacy of NX nanofiltration membranesin the filtration of water contaminated with PFAS. The originality of these membranes relies in the hollow fiber configuration which is still rare for nanofiltration [3]. The NX nanofiltration membranes, characterized by their fine pore size and high selectivity, present a promising solution. The experimental setup involves exposing the membranes to a controlled concentration of PFASladen water and monitoring their performance in terms of removal efficiency, flux rates, and durability. The goal is to investigate the membrane's ability to selectively reject PFAS molecules while maintaining optimal water permeability. The concentrate solution will be analyses by PhD 2 and tested by Dr. Cavailles’s group and PhD 3.The concentrate will then be treated by electrochemical oxidation in task 3.

Task 2. Design of porous calcium copper titanate membrane electrodes In this task, we will investigate the synthesis of perovskite porous based electrodes. Perovskite oxides (specially CaCu3Ti4O12 (CCTO)) are particularly popular in electrocatalysis due to their lowcost and simple synthesis techniques with excellent stoichiometric control, repeatability, and homogeneity. They also offer a high capacity to accommodate a wide variety of substituting and doping elements to regulate their properties. We will first synthesize this perovskite and study the doping with different elements (Silver, Cobalt etc.) in order to enhance the electrocalytic properties. The preparation of porous membrane (macro/meso) will be realized using a templating approach (PMMA, Polycarbonate spheres etc.) in order to obtain material with controlled porosity. The obtained membranes will be characterized by various approaches including SEM, TEM, EDX, XPS, XRD, Raman and FTIR.

Task 3. Batch reactivity for removing persistent pollutants In this task, PFAS concentration will be in the range 5-20 ppm to avoid analytical issues. First, we will identify the reaction mechanisms using radical quenchers and probe molecules (e.g. terephthalic acid for •OH). Then, we will evaluate the kinetics and the pathway for the degradation and mineralization of selected pollutants, the evolution of by-products (degradation by-products; ClO3- and ClO4-) and the competition with scavengers. In addition, we will quantify the reactivity of perovskite powders for activation of externally added H2O2 and/or S2O8 2- /HSO5 - ; the reactivity of the suspension of catalysts in a batch electrochemical reactor used for in situ production of H2O2 (from reduction of dissolved O2 at carbon-based materials) and/or S2O8 2- /HSO5 - (from sulfate oxidation at TiO2-x or boron-doped anodes); and the reactivity of catalysts immobilized on electrode surface in a batch electrochemical reactor. Finally, we will quantify the influence of electrode polarization and water matrix on the lifetime of catalysts: using an approach based on accelerated lifetime tests.

Task 4. Flow-through validation over catalysts using nanofiltration concentrates First, we will optimize the porosity of CCTO membrane and we will study mechanical stability (shock and attrition tests). Then, we will determine the optimal configuration of the flow-through reactor with model pollutants. We will validate the flow-through configuration for treatment of model water. Finally, we will apply and optimize the treatment of nanofiltration concentrates as performed in previous study in IEM [4]. The treated solution will be analyzed by PhD 2 and tested by Dr. Cavailles’s group and PhD 3.

Expected results

The completion of this research project will definitely lead to a treatment scheme dedicated to the eradication of PFAS for drinking water production. This project will allow to obtain the first prove of concept for electrochemical water purification using perovskite based membrane. It could lead ultimately to a substantial industrial valorization through several industrial partners that have close collaboration with our laboratory. Feasibility The feasibility of this project is based both on the expertise of the host laboratory and the wide national and international collaborations already in place. In addition, this project benefits from the technical and scientific support of a scientist and a technician. All the facilities necessary for the implementation of the project are already available within the IEM.

Candidate profile: The candidate (M/F) should hold a Master's or Engineering degree in Materials Science, Chemistry, Process Engineering, Physical Chemistry, or a related field. The candidate should have strong foundational skills and an inclination for experimental work in the laboratory. Excellent writing and communication skills, particularly in English, are required, along with the ability to work independently. Previous experience in membranes would be advantageous.

1 Tow EW, Ersan MS, Kum S, Lee T, Speth TF, Owen C, et al. Managing and treating per- and polyfluoroalkyl substances (PFAS) in membrane concentrates. AWWA Water Sci. 2021;3(5):1–23. 2 Mirabediny M, Sun J, Yu TT, Åkermark B, Das B, Kumar N. Effective PFAS degradation by electrochemical oxidation methods-recent progress and requirement. Chemosphere. 2023;321:138109. 3 Wendy A. Jonkers, Emile R. Cornelissen, Wiebe M. de Vos, Hollow fiber nanofiltration: From lab-scale research to fullscale applications, Journal of Membrane Science, Volume 669, 2023,121234,4 4 Azaïs A, Mendret J, Petit E, Brosillon S. Influence of volumetric reduction factor during ozonation of nanofiltration concentrates for wastewater reuse. Chemosphere. 2016;165:497–506.

Application procedure

The application must include the following:

• a CV
• a letter of motivation
• a copy of the degree required for registration
• any additional specific information requested by the doctoral school GAIA (https://adum.fr/as/ed/gaia/index.pl ).

If you would like to apply for this position, please send an e-mail to [email protected] and [email protected] , with a CC to [email protected]  to inform them of your interest.

Before Sunday 21 April, 8pm CET

More information availalble here (as of March 11th, 2024):

https://www.umontpellier.fr/articles/appel-a-projet-doctoral-nexus-campagne-2024

Requirements

Research Field

Chemistry

Education Level

Master Degree or equivalent

Languages

ENGLISH

Level

Good

Languages

FRENCH

Level

Good

Internal Application form(s) needed
Sujets Nexus 2024 Mendret.pdf
English
(829.09 KB - PDF)
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Additional Information
Work Location(s)

Number of offers available

1

Company/Institute

IEM Montpellier

Country

France

Geofield

Where to apply

E-mail

[email protected]

Contact

State/Province

FRANCE

City

Montpellier

Website

https://www.umontpellier.fr/

Street

163 rue Auguste Broussonnet

Postal Code

34000

STATUS: EXPIRED