Assessment of Performance of Posidona oceanica (L.) as Biosorbent for Crude Oil-Spill Cleanup in Seawater

The marine environment is constantly at risk of pollution by hydrocarbon spills that requires its cleanup to protect the environment and human health. Posidonia oceanica (L.) (PO) beach balls, which are characteristic of the Mediterranean Sea and abundant on the beaches, are used as biosorbent to remove hydrocarbons from the sea. The impact of several factors such as oil concentration, time sorption, and weight sorbent was investigated to determine the oil and water sorption capacity for raw and milled P. oceanica fibers. The study of kinetic models for initial crude oil concentration of 2.5, 5, 8.8, 10, 15, 20, 30, and 40 g/L revealed that crude uptake followed the pseudo-first-order model while, for isotherm models, the crude uptake onto the P. oceanica tended to fit the Langmuir model. Experiments were performed according to two systems: a pure oil and pure water system and a mixed oil/water system. For the dry system (pure oil and pure water), the maximum oil and water sorption capacity of raw and milled fibers was found to be 5.5 g/g and 14 g/g for oil and 14.95 g/g and 15.84 g/g for water, respectively, whereas, in the mixed oil/water system, the maximum oil and water sorption capacity was estimated as 4.74 g/g, 12.80 g/g and 7.41 g/g, 8.31 g/g, respectively. The results showed that, in spite of their absorbency of a lot of water, the milled fibers with grain size ranging between 0.5 mm and 1 mm might be the relevant sorbent for the elimination of crude oil from seawater thanks to its efficient sorption capacity and low cost.