Advancing in-situ oil-contaminated soil remediation through microfluidic studies of plant-based surfactants

Crude oil is considered hazardous because of its toxic chemical composition, which can pose significant health and environmental risks. Therefore, the decontamination of crude oil from soil is a critical issue in the current global environment and for the sustainable development of countries. This study investigates the removal of oil from contaminated soil using plant-based saponins. After extraction and purification, the critical micelle concentration (CMC), surface tension, micelle size and shape, and emulsifying and foaming properties are evaluated. To our knowledge, this is the first application of freezing point osmometry for the determination of CMC in saponins from Alfalfa and Glycyrrhiza glabra. Furthermore, the study examines the performance and economic aspects of oil-contaminated soil remediation in microfluidic systems, with and without connate water. The study demonstrates that the extracts exhibit favorable properties as natural surfactants, and their remediation performance is more efficient in the presence of connate water, particularly when an economical injection strategy is employed.