POLYOLEFINS AND WASTE POLYOLEFINS-BASED MATERIALS FOR OIL/WATER TREATMENT

Abstract

Water pollution is a critical threat to marine ecosystems, human health, and environmental sustainability. In parallel, global accumulation of plastic waste poses long-term ecological and socioeconomic risks. Although these two challenges are typically addressed independently, this work explores an integrated approach that leverages waste polyethylene (PE) as a value-added material for oily wastewater treatment, thereby contributing simultaneously to pollution reduction and circular resource utilization. In the first phase of this study, waste PE was chemically modified through plasma-induced grafting of a cationic monomer to enhance surface wettability and affinity toward oil droplets. The modified PE was assessed for produced water treatment under both batch and filtration configurations, achieving removal efficiencies of approximately 75% in batch mode and 65% in filtration mode. The second phase focused on converting PE waste into a foamed sorbent material for oil spill remediation. Fabricated PE exhibited high 1.4 g/g oil uptake performance within one hour. In the third phase, waste LDPE was coated with a tailored polymeric layer synthesized via radiofrequency plasma polymerization of allylamine to promote interaction with negatively charged oil droplets. The resulting sorbent demonstrated a separation efficiency of 60% for 100 ppm oil in water emulsions under acidic conditions. Aligned with the broader theme of plastic waste valorization, the final component of this work investigates the potential use of oxidatively aged oxo-biodegradable polyethylene (oxo-PE), a material that remains environmentally persistent despite claims of rapid degradation. Commercial oxo-PE bags were subjected to photo-thermal accelerated weathering for up to 90 days, producing oxidized fragments subsequently tested as sorbents for SDS and CTAB stabilized oil in water emulsions. Aged oxo-PE achieved separation efficiencies of 51% (SDS) and 46% (CTAB), offering a possible secondary application route for this controversial material. Collectively, this dissertation demonstrates sustainable, experimentally validated pathways for converting polyethylene waste into effective sorbents for oily-water treatment, advancing circular-economy solutions while addressing wastewater and plastic pollution challenges.

Date of Award	2026
Original language	American English
Awarding Institution	HBKU College of Science and Engineering