Vegetable oils as surfactant feedstocks for enhanced oil recovery: A review

Abstract

Extensive studies have been conducted on the efficacy of vegetable oils as surfactant feedstocks for enhanced oil recovery. This has become necessary owing to environmental concerns and high costs of synthetic surfactants. In this review, three stages of screening criteria for vegetable seeds and oils as surfactant feedstock have been identified. The first stage involves the selection of vegetable seeds and peels that are agro-waste, non-edible, abundant, and biodegradable; the second stage considers the physicochemical properties of vegetable oils, especially those with long chain monounsaturated fatty acids; and the third stage considers surface-active properties, thermal stability, oxidative stability, and oil-recovery efficiency of vegetable oil-based surfactants. Previous findings suggest that vegetable oil-based surfactants that have high fractions of long chain monounsaturated fatty acids have good surface-active properties, while those with saturated fatty acids have thermal and oxidative stabilities. Despite these findings, current research works have largely ignored vegetable seeds and oils that satisfy the screening criteria elucidated in this review. Consequently, the physicochemical properties of vegetable seeds and oils that have been ignored as surfactant feedstocks are reviewed. Challenges of the use of vegetable oils as surfactant feedstocks and possible remediation strategies are presented.