(190g) Green(er) Solvents for Upcycling Waste PVC into Membranes

The increasing levels of plastic pollution have led to a growing threat to wildlife and ecosystems. One step towards sustainability is upcycling plastic waste into high-value-added products, such as membranes for water treatment. However, the use of organic solvents in the upcycling process of waste plastic into membranes raises serious concerns due to their adverse environmental and health effects. To enhance the eco-friendliness and sustainability of this process, this study investigates the use of green(er) solvents, such as dihydrolevoglucosenone (Cyrene) and triethyl phosphate (TEP), for upcycling waste PVC pipes into ultrafiltration membranes. The rheological and thermodynamic behavior of waste PVC pipe casting solutions with these two solvents were analyzed, along with the properties (pore morphology, size, surface charge, and surface roughness) of the upcycled PVC membranes. Additionally, the effect of additives such as calcium carbonate and carbonyl group possessing compounds present in the waste PVC pipe on the casting solution, membrane structure, and, consequently, on the performance of the upcycled membranes was assessed. The upcycled PVC membranes were benchmarked against similar membranes fabricated using organic solvents and commercial membranes. The additives affected the pore morphology and surface charge of the upcycled membranes. The upcycled PVC membranes exhibited permeability (26.1 LMH/bar with Cyrene and 56.9 LMH/bar with TEP) and dye rejection (94.6 % with Cyrene and 72.6 % with TEP) comparable to similar membranes fabricated using organic solvents and commercial membranes.