Lemon and Lime Peel Organic Media for Metal Removal from Crude Oil

Abstract

Crude oil contains trace metal species that hinders performance during refining, poison catalysts, and results to environmental contamination. Conventional metal-removal processes, such as hydrotreating and solvent extraction, are energy-intensive and costly.
In this study, organic wastes such as lemon and lime peel were evaluated as alternative media for extracting metal-containing complexes from crude oil. Model experiments using copper, iron, and nickel phthalocyanines dissolved in toluene showed that all
complexes were transferred intact into the adsorbent. Hydroxylated species and free ions coupled with the pH of the adsorbent were suspected as the major factors responsible for extraction. Across the formulations tested, more acidic organic waste systems consistently delivered higher extraction efficiencies. The methodology was then applied to a Nigerian crude oil sample to assess performance under realistic conditions.
Organic waste effectively extracted metalloporphyrin and other metal species while maintaining good phase separation. A simple filtration-based workflow enabled recovery of the organic waste with minimal energy input, demonstrating the potential for operationally straightforward and metal-removal processes. Overall, this work establishes lemon and lime peel as efficient, mechanistically understood, and potentially low-energy media for the extraction of metal species from crude oil, offering a promising basis for next-generation upgrading technologies