L. DUMEE
"Limiting the interactions between nano/microplastics and water filtration membranes using plasma surface treatment"
The contamination of worldwide waters and ecosystems by plastic litter has turned plastic pollution into a serious environmental problem. Among all plastic pieces, microplastic fragments and fibers constitute a real threat for aquatic species and human health. Although a growing number of studies have investigated the environmental impact of nano/microplastics, knowledge on the occurrence and behavior of nanoplastics (NPs) and nanofibres (NFs) in water is limited. Common analytical methods are not appropriate to detect and analyze NPs and NFs due to their shape and nanometer size. The main concern relies on the fate of NPs and NFs through water treatment plants since processes used to treat water can be impacted by the presence of these nano-sized fragments and fibres, such as ultrafiltration membranes. Membrane can suffer from fouling due to the adsorption of species on their surface which decreases their filtration performance, however, the fouling mechanism of NPs and NFs remains unclear. Investigating the fouling of NPs and NFs on filtration membranes is therefore necessary to develop a solution preventing fouling from occurring and keep membrane performance to a high level.
The present work aims at studying the fouling of poly(ethylene) fragments and textile poly(ester) fibres on commercial ultrafiltration membranes. The membrane surface was subsequently enhanced by plasma polymerization to induce the repulsion of fragments and fibres from the membrane surface. Fouling mechanism was followed by measuring permeate water flux and turbidity measurements were combined to optical imaging to quantify the amount of fibres in water. Nanoparticle Tracking Analysis was used to quantity the amount of fragments in water. Membrane surface properties such as roughness and hydrophilic were assessed before and after filtration to understand the impact of NPs and NFs on the structural and chemical properties of the membrane. Results suggest that the plasma layer reduced the fouling of NPs and NFs by decreasing the amount of NPs and NFs adsorbed on the membrane which kept permeate water flux decline to a low value.