Context and objectives
During laundry washing, fibers are inevitably shed from textiles and are carried into the wastewater. These fibers, typically around 10 μm in diameter, vary in composition
- mainly polyester and cotton
- and recovering and separating them remains a significant challenge, particularly for recycling synthetic fibers.
Simply extracting them is also a crucial challenge for water decontamination, as textile polymer fibers represent for instance 60% of the microplastics found at the surface of Lake Geneva.
Traditional membrane filtration methods are costly and inefficient, often suffering from issues like membrane clogging and the need for high pressures. Additionally, water-evaporation based processes are not energetically sustainable. Alternatively, we consider here the flotation process, which consists of creating gas bubbles within the liquid to which the fibers will attach and thus be captured. Flotation is a common process in industry. However, little is known on how it is affected by the geometry of fibers. Besides, in waste water,
surfactants (laundry detergents) can be present, which may affect the wetting properties of the fibers and their ability to attach to bubbles.
Work plan
The capture process is three-step: collision, attachment and possibly detachment. We will focus here on attachment. We will use videomicroscopy to quantify the probability of adsorption on a single bubble placed in a fiber suspension. These measurements will be coupled with characterizations of the physicochemical properties of the solution-fiber couples (surface tension and contact angle), for different types and concentrations of surfactants that are present in laundry formulations. These measurements performed at ILM will be complemented by the development of a theoretical model to predict collision efficiency, and by pilot scale experiments performed at IFPEN.
Keywords: flotation, fibers, attachment
- Academic supervisor Prof Anne Laure Biance, Institut Lumière matière, ORCID : 0000-0002-3120-7595
- Doctoral School Ecole Doctorale Matériaux de Lyon
- IFPEN supervisor Dr Jean-Lou Pierson, ORCID : 0000-0002-6231-1424
- PhD location ILM / IFPEN Solaize
- Duration and start date 3 years, starting in the fourth quarter 2025 (Novembre 3)
- Employer IFPEN
- Academic requirements University Master degree in Fluid mechanics
- Language requirements English level B2 (CEFR)
To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.