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MSc assignment: development of reactive electrochemical membranes

                                             

Inorganic Membranes group              The Photocatalytic Synthesis Group

Development of reactive electrochemical membranes

Objective

In this project, the candidate will prepare and characterize reactive electrochemical membranes using 2D Ti4O7 nanosheets. During the project the candidate will benefit from the expertise and equipment of the Photocatalytic Synthesis and Inorganic Membrane groups.

 

Project description

Sub-stoichiometric titanium oxides (TinO2n−1, n = 4 to 10)-based Reactive Electrochemical Membrane (REM) technology offers an economically attractive solution for the treatment of wastewater streams1. REM relies on a combination of physical and chemical separations to convert wastewater organic contaminants (OCs) into non-toxic compounds such as water and carbon dioxide. In this system wastewater flows through a porous membrane acting as electrode (anode), resulting in enhanced conversion rates of the targeted contaminants compared to traditional flow-by electrodes. The following electrochemical oxidation reactions occur via: a) direct electron transfer reaction from the contaminant to the REM and b) water oxidation at the REM surface at high O2 overpotential, inducing the formation of large quantities of highly reactive hydroxyl radicals (OH) 1.

Sub-stoichiometric titanium oxides (TinO2n−1, n = 4 to 10)-based REM can produce a high quantity of OH and are used for the electrochemical degradation of various organic pollutants or as electrically-assisted antifouling filtration systems. Here, the Ti4O7 phase is desired because of its high conductivity (≈ 1000 S.cm‑1), (electro)chemical stability, and high selectivity for OH formation. Besides the importance of the phase, to obtain optimal performance a thin filtration layer with high porosity, suitable pore size, and low tortuosity are important to achieve high permeability, to avoid diffusion limitations, and to have sufficient membrane/water interaction to reach a high electrochemically active surface. In this project, we will prepare such type of thin filtration REM by deposition of 2D Ti4O7 nanosheet on top of a porous ceramic support.2 Adjusting the preparation conditions will enable to tune the thickness and pore size to increase the resulting electrochemical active surface. The potential of this new 2D Ti4O7 nanosheet layer as a reactive electrochemical membrane will be assessed by conducting a series of electrochemical oxidation tests and by comparing with reference sub-stoichiometric titanium oxides REM.

Figure 1. Overview of the project objective.

Skills

During the project the student will develop the following skills:

-  Synthesis and characterization of sub-stoichiometric titanium oxides REM

-  Electrochemical oxidation measurements

 

Reading

1. Trellu, C. et al. Electro-oxidation of organic pollutants by reactive electrochemical membranes. Chemosphere 208, 159–175 (2018).

2. Takimoto, D., Toda, Y., Tominaka, S., Mochizuki, D. & Sugimoto, W. Conductive Nanosized Magnéli-Phase Ti4O7 with a Core@Shell Structure. Inorg. Chem. 58, 7062–7068 (2019).

 

Contact : Marie Pizzoccaro-Zilamy (IM), email: m.d.pizzoccaro@utwente.nl; Bastian Mei (PCS), email: b.t.mei@utwente.nl