Surfactant-enhanced mobilization of polycyclic aromatic hydrocarbons from an historically contaminated marine sediment: Study of surfactants’ concentration effect and continuous test for sediment flushing simulation

Abstract

Contamination of marine sediments by polycyclic aromatic hydrocarbons (PAHs) poses a significant environmental threat, necessitating effective remediation strategies. This paper investigates the application of surfactants, both synthetic and natural, for the remediation of PAH-contaminated sediments, providing a systematic guideline for the preliminary selection of surfactants for flushing/washing operations, the optimal operative conditions, and the technical approach for PAH mobilization, especially in the context of a real aged contamination scenario. The study included a batch configuration test to evaluate the effect of surfactant concentration on PAH mobilization. Subsequently, a continuous configuration column experiment was performed to simulate a flushing operation of contaminated sediment. The study of process conditions highlighted that the increase in surfactant concentration led to a significant increase in PAH removal from the sediment, reaching almost 30 % efficiency using a 5 % wt surfactant solution. The column test showed great efficiency of the investigated surfactants in PAH mobilization through the flushing process of the contaminated matrix, resulting in 30 times greater efficiency than water within a much smaller pore volume range. • A polluted marine sediment with highly recalcitrant compounds from an Italian National Priority Site was used for the study. • Sediment chemical characterization showed the presence of 16 different PAHs with a total concentration equal to 3.51 g Kg −1 . • Column experiment were performed to simulate a sediment-flushing operation as a novel strategy to remediate polluted matrix. • Surfactants senhanced PAHs mass transfer from the sediment to the aqueous phase in a very small pore volume range. • Continuous configuration process led to a greater PAHs removal than the more traditional batch configuration sediment washing.