Surface-modified Alginate Bioplastics: Biodegradable Sorbents for Selective Oil Spill Remediation

Abstract

Background: Marine oil spills require effective sorbent materials that combine selective oil uptake with biodegradability to reduce the secondary pollution associated with conventional polypropylene products. Aims: This study aims to develop and evaluate a biodegradable, surface-modified calcium alginate composite sorbent as an alternative to commercial polypropylene materials for selective oil-spill remediation. Study Design: An experimental materials-development study comparing seven alginate-based formulations with a commercial polypropylene sorbent. Place and Duration of Study: STEM Science Center, Englewood Cliffs, New Jersey, USA, during 2025-2026. Methodology: Sodium alginate was reinforced with cellulose nanofibers, supported on biodegradable gauze, cross-linked with calcium chloride, and surface-modified with beeswax nanoparticles. The formulations were evaluated for 24-h oil absorption, 30-day soil biodegradation at 0, 25, and 37°C, tensile strength, scanning electron microscopy, and thermal-decomposition behavior using temperature, humidity, optical, and MQ-7 gas sensing. Measurements were performed in triplicate where applicable. Results: The optimized alginate composite absorbed 374.25% of its dry mass in oil, equivalent to 72.4% of the 516.65% uptake achieved by polypropylene. The alginate sorbent showed an average mass loss of 32.06% over 30 days, whereas polypropylene showed essentially no biodegradation. The composite also achieved a mean tensile-load resistance of 1.88 kg, compared with 1.54 kg for polypropylene. Microscopy supported the presence of a hierarchical porous structure produced by the gauze scaffold, alginate matrix, cellulose nanofibers, and beeswax modification. Conclusion: Surface-modified alginate composites offer a promising balance of oil uptake, mechanical handling, and biodegradability. Further testing with crude oil, standardized combustion analysis, scale-up, and field deployment is required.