Journal of Environmental Management 268 (2020) 110688 Available online 14 May 2020 0301-4797/© 2020 Elsevier Ltd. All rights reserved. Research article Assessment of milkweed foss as a natural hollow oleophilic fbrous sorbent for oil spill cleanup Shima Panahi a , Meghdad Kamali Moghaddam b, * , Meysam Moezzi b a Department of Polymer Science and Engineering, Faculty of Engineering, University of Bonab, 5551761167, Bonab, Iran b Department of Textile Engineering, Faculty of Engineering, University of Bonab, 5551761167, Bonab, Iran A R T I C L E INFO Keywords: Capillary Milkweed fber Oil pollution Turbidity Wetting behavior ABSTRACT Natural oil sorbent materials with a high oil sorption capacity have recently received remarkable attention for oil spill cleanup from seawater. This study reports on the development of a superhydrophobic hollow cellulosic fber that could serve as an oil spill cleanup material. As oil sorption is based on the physical and chemical charac- teristics of the sorbent, FTIR, SEM, XRD, and surface contact angle of the fbers were determined. A series of tests were then carried out to analyze the sorption capacity, dynamic oil retention, and reusability. Subsequently, the effect of the fbers’ weight on the amount of oil absorption and absorption time was investigated. The wettability analyses showed that the milkweed foss fber possessed a superhydrophobic characteristic (with the water contact angle of 140 � ). The empty channel of the fber was more than 90% of its total volume. The hydropho- bicity and capillary properties helped the fbers to absorb up to 100 g/g of oil, which was higher than that obtained by many natural cellulosic fbers. 1. Introduction Generally, most petroleum products including crude oil have low density and foat on the surface water when spilled. In the last decades, oil pollution resulting from oil spillages has raised serious concerns, urging environmental researchers to look for a good solution. Numerous publications have introduced a low-density fber to foat on water for oil cleanup (Choi and Cloud, 1992; Idris et al., 2014; Johnson et al., 1973; Karan et al., 2011). Polypropylene is one of the well-known inorganic sorbents used to absorb spilled oil (Rengasamy et al., 2011; Sęk et al., 2013). Despite its good absorption capacity and low density, this fber has a low retention ability and is non-degradable and non-renewable. The researchers have, therefore, tried to fnd a biodegradable sorbent with low water uptake and high oil sorption capacity. Johnson et al. investigated the potential of unstructured natural fbers (e.g. cotton and wool) and synthetic fbers (e.g. viscose, acetate, polypropylene, acrylic, nylon, and polyester) as oil sorbent materials against crude oil (Johnson et al., 1973). It was found that cotton fber had the highest oil sorption capacity (40 g/g) and was higher than that of wool, polypropylene, and Polyester fber (Sabir, 2015). Choi et al. also found that milkweed fber (40 g/g) had the highest oil sorption capacity against light crude oil (0.854 g/cm 3 ) among of kapok (38 g/g), cotton (32 g/g), wool (31 g/g), polypropylene (12 g/g), and kenaf (5.6 g/g) fbers (Choi, 1996). Since hydrophobic properties and void fraction are the two factors affect the oil sorption capacity of fbrous sorbents (Likon et al., 2013), cellulosic materials from agricultural and industrial wastes with a hydrophobic surface and a hollow structure are of interest to researchers (Abdelwa- hab, 2014; Lim and Huang, 2007; Rengasamy et al., 2011; Wang et al., 2012). Oil wicking into the lumens of the cellulosic fber held by capillary forces is the main reason for its high oil sorb capacity (Hubbe et al., 2013; Idris et al., 2014). Also, the oleophilic properties of some cellulose fber’s surface are a cause of well adheres between oil and the hydrophobic surface of the fber (Huang and Lim, 2006). Some studies indicated that hydrophobic modifying of the hydrophilic cellulose fber resulted in increases of the oil sorption capacity (Li et al., 2013; Sun et al., 2002; Sun et al., 2004; Teli and Valia, 2013a, b; Wang and Wang, 2013; Yang et al., 2016). In the last decade, some researchers had tried to study other avail- able natural fbrous sorbents and evaluated them according to sorption capacity and availability. Karan et al. studied the effect of fber assembly structure (cotton, kapok, milkweed, and polypropylene) on oil spill cleanup. The results showed that the order for engine oil (0.9 g/cm3) * Corresponding author.. E-mail addresses: sh.panahi@ubonab.ac.ir (S. Panahi), kamali@ubonab.ac.ir (M.K. Moghaddam), meysammoezzi@ubonab.ac.ir (M. Moezzi). URL: http://www.researcherid.com/rid/V-4958-2018, https://rtims.ubonab.ac.ir/~mkamalimoghadam/en/ (M.K. Moghaddam). Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: http://www.elsevier.com/locate/jenvman https://doi.org/10.1016/j.jenvman.2020.110688 Received 11 March 2020; Received in revised form 14 April 2020; Accepted 30 April 2020