Sorption of oils by the nonliving biomass of a Salvinia sp.

The sorption of oils onto the dry biomass of the aquaphyte Salvinia sp. was studied at laboratory scale, and the results were compared to that obtained with a commercial oil sorbent, Feat Sorb, a processed neat. Studies included physical, chemical, and physicochemical characterization of the aquaphyte and the peat. The Salvinia sp. biomass was a better sorbent for oil than Feat Sorb (for a crude oil, 4.8 against 2.7 g of oil sorbed per g of biomass). Main factors that control the sorption process were the hydrophobicity of the biomass, particle size, the chemico-physical composition of the plant and the sorbate, and the capillary suction displayed by the plant biomass. The leaves of the plant, distributed primarily in the fraction greater than 1 mm, contain the majority of the hydrophobic groups, coming from microstructures (cuticular folds and wax crystal) and epicuticular wax. The capillarity may arise from both the micropores and from the interstices between hairlike surface projections; The roots, mainly the fraction less than 1 mm, contain a smaller percentage of hydrophobic groups, most of the mineral constituents lash), and higher surface area land porosity). Together, the hydrophobicity and the capillary effect due to pore structure of the plant and its parts are responsible for the oil sorption and the differences found. Technical implications of the practical use of this plant are considered in the final discussion.