Remediation of Crude Oil Spill on Water by Waste Poly(ethylene)- derived Sorbent

This research addresses two major environmental concerns: the growing accumulation of waste water sachet polyethylene (WWSP), which poses a significant environmental nuisance, and the need for effective sorbents for crude oil spill remediation on water surfaces. This study explores the transformation of WWSP into high-performance oil sorbents through mechanical and weathering (artificial and accelerated to simulate natural environmental ageing) modifications. Comprehensive characterisation of both PE and crude oil (natural and synthetic) was conducted to understand their chemical composition and interfacial properties. Contact angle measurements were performed to evaluate the hydrophobicity and oleophilicity of different forms of PE. DSC, TGA and FTIR were performed on the PE to investigate their chemical composition and thermal behaviour. SEM was carried out on the various types of PE (before and after modifications) to assess their surface morphology. GC-MS, TGA, and Rheology were used to determine the oil’s chemical composition, volatility, thermal stability, and viscosity under shear stress. I-optimal design of experiments was employed to systematically assess the impact of adsorbent quantity, particle size, adsorbent type, and UV-weathering duration on adsorption capacity and efficiency. The results highlighted strong interactions between these factors, significantly influencing sorbent performance. Results reveal that waste PE-based sorbents are made up of LLDPE and LDPE at almost equal proportions. These sorbents exhibit significant oil adsorption capacities when modified mechanically or physically (UV-weathered). Shredded PE reaches up to 7.1 g/g with reusability of 18 cycles, then when roughened (Shredded-roughened PE) achieves an increased adsorption capacity of 8.6 g/g, UV-weathered PE, exposed to high values of irradiance (1.55 W/m2 ) and temperature of 70oC, shows an adsorption capacity of 6.5 g/g after 75 hours and declines to ≤3.5 g/g after 150 hours. The findings highlight the critical role of surface area and roughness in enhancing oil retention by improving sorbent-oil interactions. Additionally, moderate weathering enhances adsorption capacity, though prolonged exposure leads to a decline. Oil type affected adsorption, with lighter oils being adsorbed faster due to lower viscosity. Smaller particle sizes (2.8 mm ≤ x ≥ 2.0 mm) increased surface area giving higher adsorption capacity, and efficiency up to 100% but became less effective beyond the optimal loading capacity. These insights reinforce the potential of waste PE as a low-cost, sustainable solution for oil spill cleanup. Overall, this research has demonstrated that waste polyethylene that littered the environment can be used in a simplified manner to clean up crude oil spilt on the water even after lying in the environment for some period and contributing to sustainable environmental management and efficient oil spill remediation technologies.