Development of Piliostigma reticulatum Fiber-Based Sorbents for Crude Oil Spill Remediation in Water Obtained from Ogoniland, Nigeria’s Niger Delta

Abstract

Oil pollution in aquatic environments remains a serious environmental challenge, particularly in oil-producing regions such as Nigeria’s Niger Delta. This study focused on the development of natural fiber-based sorbents from Piliostigma reticulatum for crude oil spill remediation. The fibers were extracted from the bark of Piliostigma reticulatum using chemical retting with 6% sodium hydroxide solution, followed by scouring and bleaching treatments to improve fiber purity and sorption efficiency. The extracted fibers were categorized as crude, retted, and bleached fibers. Physical characteristics such as fiber length, diameter, color, and texture were determined, while physicochemical properties including moisture content, density, specific gravity, and swelling ability were analyzed using standard laboratory procedures. Oil sorption experiments were conducted in batch systems to evaluate the influence of sorbent weight (0.10–0.60 g), contact time (10–70 min), and initial oil concentration (5–20 g/100 mL) on sorption capacity in water medium, while additional tests were performed in oil-only medium to assess maximum sorption potential. The unbiased results showed that chemical treatment significantly improved the properties of the fibers. The mean fiber length increased from 8.40 cm in crude fibers to 9.60 cm in bleached fibers, while the diameter decreased from 0.42 mm to 0.31 mm, resulting in smoother and finer fibers. Moisture content decreased from 12.80% in crude fibers to 7.20% in bleached fibers, while swelling ability increased from 46.20% to 71.40%, indicating improved sorption potential. The crude oil used in the study had a density and specific gravity of 0.882 g/cm³ and an API gravity of 28.5°. Sorption studies revealed that oil sorption capacity decreased with increasing sorbent weight but increased with higher oil concentration. Equilibrium was reached within 30 minutes. The maximum sorption capacity in water medium was 9.40 g/g for bleached fibers, followed by 7.10 g/g for retted fibers and 5.50 g/g for crude fibers. In oil-only medium, the highest sorption capacity recorded was 11.60 g/g for bleached fibers. Generally, the results demonstrate that chemically treated Piliostigma reticulatum fibers, particularly bleached fibers, exhibit excellent oil sorption capacity and can serve as effective, low-cost, and environmentally friendly sorbents for crude oil spill remediation. The use of this abundant natural fiber provides a sustainable approach for mitigating oil pollution in aquatic environments, especially in oil-impacted areas of the Niger Delta.