(322b) Green Solvents for Upcycling Waste PVC into Ultrafiltration Membranes for Water Treatment

The increasing levels of plastic pollution have resulted in a growing threat to wildlife and ecosystems. Taking immediate action to stop this environmental threat and promote sustainable solutions is imperative. One step towards sustainability is to upcycle the plastic waste to high-value-added products such as membranes for water treatment. Non-solvent-induced phase separation (NIPS) using organic solvents is a standard process for membrane fabrication. These organic solvents, such as tetrahydrofuran (THF), N,N-dimethylformamide (DMF), pose environmental and health hazards as they are toxic and harmful to human health. To improve the eco-friendliness and sustainability of the waste plastic upcycling process, we have investigated the use of green solvents, such as Dihydrolevoglucosenone (Cyrene) and Triethyl phosphate (TEP), for the upcycling process of waste PVC pipes. These upcycled PVC pipe ultrafiltration membranes were thoroughly characterized to evaluate the impact of these two green solvents on membrane physicochemical properties. Each of these green solvents imparted distinct properties to the membrane. For instance, membranes prepared with Cyrene exhibited a sponge-like morphology, while those prepared with TEP showed a finger-like morphology. The performance of these upcycled membranes was also evaluated in terms of pure water permeability and Direct Red 80 (DR-80) dye rejection. The upcycled PVC pipe membranes exhibited impressive permeability (25 LMH/bar with Cyrene and 55 LMH/bar with TEP) and excellent DR-80 rejection (94.64% with Cyrene and 72.58% with TEP), demonstrating the significant potential for these green solvents for upcycling the waste PVC pipes into ultrafiltration membranes.