A study of penetration of oil into sorbents

Abstract

This study was initiated to absorb petroleum spills in sea waters. For this purpose, polyurethane and polypropylene were used as sorbents, and SAE 20W-20 motor oil and SAE 90W gear oil were used as oils. To observe the penetration of oils into sorbents, four groups of experiments were carried out the horizontal penetration of oils into dry polyurethanes, the horizontal displacement of water from polyurethanes (pre-wetted with water) by oil, the vertical penetration of oils into drypolypropylenes, and the vertical retention of oils by polyurethanes (pre-wetted with oil). Sorbents are characterized by their porosities, thicknesses, and fiber diameters. Such properties of .the sorbents used were obtained from the literature. The important properties of an oil are the density, the viscosity and the surface tension coefficient. The values for the density and the viscosity of oils used were supplied by Mobil Oil Company in Istanbul. The surface tension coefficients of these oilS also were measured in Bogaziçi University Labs. The sorbent/oil contact angle, which is another important parameter, was taken as zero by assuming that the sorbents were completely wetted with oil. A linear model, developed in literature for the horizontal penetration of oils into sorbents, was used in this study, and the experimental results obtained in this study did not agree with this model. Here, the distance penetrated by oil into sorbents was observed to be directly proportional to the square root of time. In addition, the horizontal displacement of water from sorbents by oil was also studied here. The polyurethane samples (pre-wetted with water) did not absorb oil, that is, water prevented the penetration of oil into Sorbent. Therefore, the displacement of water from sorbents by oil could not be achieved. This indicates that the sorbents can absorb oil from the surface of sea waters, if they are prevented from being wetted. The verticalpenetratjon rate model, taken from the literature, is nonlinear. The vertical retention model, which was·developed in this study, is also nonlinear. The experimental and the theoretical results showed that both the vertical penetration rate and the vertical retention were nonlinear. In the vertical penetration rate experiments, the rate at which oil climbed up the soroont was measured. In the vertical retention experiments, the rate at which oil drained from the sorbent was measured. The evalua.tions were based on these measurements.