Temperature Effect on Oil Sorption and Wettability of Kapok Fiber

Abstract

Kapok fiber as a natural sorbent with excellent hydrophobic-oleophilic characteristic was studied. The effect of temperature on oil sorption behavior and wettability of kapok fiber powder was quantitatively evaluated by capillary rise method. Results showed that at the packing density of 0.1 g/cm3, the oil sorption capacity of kapok fiber powder presented only about 5% difference when the temperature ranged from 20°C to 90°C, with the values to engine oil, mineral oil, and PAO4 ranging from 10.96 to10.42 g/g, 10.73 to 10.18 g/g, and 10.25 to 9.89 g/g, respectively. However, the sorption coefficient which related to the sorption rate increased almost exponentially with the increasing of temperature. Then, the oil wettability of kapok fiber powder was further investigated from the perspective of contact angle. Nearly logarithmic increment in contact angle between the fiber powder and test oil was observed when higher temperature condition was applied, indicating that the enhancement of temperature apparently weaken the wettability of oil to solid powder. The adhesion work between fiber powder and oil was evaluated based on Young–Dupré equation, which suggested that higher temperature lead to lower adhesion work. Outcomes from this research are believed to provide importance reference for the usage of kapok fiber as sorbent when different temperatures are applied.

Keywords

• kapok fiber
• oil sorption
• temperature
• contact angle
• adhesion work