Oil Sorption of Non-woven Biological Mats

Abstract

Abstract. Oil spills are inevitable with the current state of the industry. The Bakken formation in North Dakota operates in frigid, dry conditions during the winter months. Synthetic pads, such as polypropylene, are used for small cleanups. However, the synthetic sorbents have unfavorable characteristics such as slow degradation and high brittleness at low temperatures. The objective of this research study was to evaluate the sorption characteristics of selected natural fiber mats under low temperature conditions. Three non-woven biological mats, which have better low temperature characteristics, were characterized against polypropylene pads at room temperature as well as frozen conditions. Hemp, flaxseed, and cotton were the biological mat types. The sorption capacity was quantified using a modified ASTM F716 Standard. Swatches of the mats, after drying and weighing, were submerged in Bakken crude oil for a designated duration at two different temperatures. The two temperatures used were room temperature (25°C) and frozen temperature (-24.9 ± 2.51°C). The post-sorption swatch was then immediately weighed to determine the maximum sorption capacity (MSC), which includes both absorption and adsorption. The results showed that cotton mat had the highest overall MSC of 11.48 ± 1.26 g oil/g sorbent at room temperature and 13.87 ± 0.38 g oil/g sorbent at frozen temperature, compared to 9.82 ± 1.04 g oil/g sorbent and 11.29 ± 1.03 g oil/g sorbent for polypropylene at the same conditions. Cotton utilizes both absorption and adsorption, which enables it for higher sorption values, as opposed to polypropylene, which only utilizes adsorption. The MSC increased significantly (15-31%) from room to frozen temperatures, with the highest increased exhibited by hemp mats. An increase in oil viscosity with decrease in temperature may have increased the adhesion of oil to the fiber mats, increasing their MSC. More research must be done on the effects of temperature on sorption capacity.