Crude oil removal using Calotropis procera

Abstract

Calotropis procera (CP) fiber is a natural and renewable material with great lumen and hydrophobic-oleophilic characteristics, providing it with a good oil absorption capacity. In order to increase the absorption efficiency of organic oils and solvents, CP fiber was treated with either 0.1 M NaOH (CPNaOH), 1% NaClO2 (CPNaClO2), or hydrothermal conditions (CPHT) in an effort to improve its ability to remove crude oil from leaks or spills. The fibers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with field emission (SEM-FEG), and wettability for water and diesel. The fibers CPHT, CPNaOH, and CPNaClO2 showed excellent hydrophobic-oleophilic properties and good crude oil absorption capacity in water 99.2 g/g, 103.9 g/g, and 92.0 g/g. The absorption after 60 min for most fibers in dry systems or with a layer of oil floating on water exceeded 90% of its absorption capacity for the time of 1440 min. The CPNaOH after 6 runs absorbed 445.8 g of crude oil per gram of fiber. Based on the results, the treated fibers can be considered an alternative for the removal of oil from leaks and spills due to the high availability and excellent absorption property for various oils.

Combined Treatment (Alkali + Thermal) of Calotropis procera Fiber for Removal of Petroleum Hydrocarbons in Cases of Oil Spill

“…Previously the fibers of Calotropis procera were removed from the interior of the fruits and manually separated from the seeds and dried at room temperature (25 ± 1 • C) for 24 h. Then, 2 g of fiber were placed in a beaker in a 10% (v/v) NaOH solution, under stirring for 1 h, according to [15]. After treatment with NaOH the fiber was washed with ultrapure water and taken to a muffle for thermal treatment, as reported by Hilário et al (2019) [14], modifying the duration of treatment from 1 h, 2 h, and 3 h [22].…”

“…The assessment of oil sorption capacity was performed using the methodology reported by [15]. An amount of 0.01 g of the fiber was immersed in the systems (O and O/W).…”

“…However, natural organic materials have the disadvantages of low selectivity and oil sorption efficiency. Some vegetable fibers with a tubular structure such as cotton, painera, cattail, and kapok fiber have shown greater oil sorption capacity than other natural organic materials and, recently, vegetable fiber from Calotropis procera [13][14][15][16].…”

“…It is a polyvalent plant, which can be used for medicinal, forage, and fuel purposes, wood and fiber production, phytoremediation, synthesis of nanoparticles, and biosorbents [19]. The species has gained prominence due to its good water repellency, high oil selectivity, hollow structure, and a wax layer on the surface, making it a potential raw material for manufacturing high-performance sorbents for removing oil from water [14][15][16][17]. Several researchers have published papers attesting to the sorption potential of Calotropis procera fiber oils, such as Thilagavathi 2020) of 92-104 g/g [14][15][16].…”

“…To improve the intrinsic properties or change the characteristics of natural fibers and biomass, these can be subjected to chemical and physical treatments, obtaining materials with new hydrophobic-oleophilic characteristics and high oil sorption capacity [15]. In previous works, Hilário et al (2019) treated the CP fiber thermally, which showed an increase in oil sorption capacity ranging from approximately 35% to 137% [14], and Anjos et al (2020) using the alkaline treatment with NaOH in the CP fiber, showed an increase in the internal diameter and gain in the surface area of the fiber, improving the oil sorption capacity by 68% when compared to the fresh fiber [15]. However, there are no studies of Calotropis procera fiber treated combining alkaline and thermal treatments for oil removal.…”