Egyptian crude oil sorbent based on coated polyurethane foam waste

Egyptian Journal of Petroleum xxx (xxxx) xxx

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Egyptian crude oil sorbent based on coated polyurethane foam waste Mohamed Keshawy ⇑, Reem K. Farag, Amany Gaffer Petroleum Applications Department, Egyptian Petroleum Research Institute, Cairo, Egypt

a r t i c l e

i n f o

Article history: Received 2 July 2019 Revised 3 November 2019 Accepted 12 November 2019 Available online xxxx Keywords: Polyurethane foam waste Coating Oil spill Networks parameters Swelling parameters

a b s t r a c t In this study, free radical polymerization of hydrophobic monomer namely lauryl methacrylate & hexadecene is coated on the flexible polyurethane foam waste as an modifier of the non-polar moiety. Also various contents of magnetic nanoparticle are incorporated to the synthesized coated polyurethane foam waste. The coated sorbers are confirmed by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The coated polyurethane waste is used to absorb Egyptian crude oil to alleviate petroleum oil spill pollution. Moreover, Swelling and network parameters including maximum oil absorption (Qmax), swelling kinetics rates, polymer solvent interaction (v), effective crosslink density (me), equilibrium modulus of elasticity (GT), and average molecular weight among crosslinks (Mc) were decided and correlated to the efficiency of the synthesized coated waste. Ó 2019 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction Environmental pollution caused by oil spill and solvent leakage in last decades caused harmful effect to ecosystem [1]. Due to its potential impact on ecosystems and subsequently human health, there is a growing demand to develop new materials for rapid removal and effective treatment methods of oils and organic pollutants from water [2]. Different methods have been proposed for treatment of oils from water, including conventional physical methods, mechanical methods (including oil booms, skimmers, oil sorbent), chemical methods (including dispersant and solidifiers), adsorption and bioremediation. [3,4]. The use of sorbent materials is one of the most effective methods due to its low cost, easy fast operation, retention over time and reusability. Meanwhile, sorption technique can be applied in large scale treatments as a final step to remove the oil remaining on the water surface. Therefore, the detection of new economic sorbent materials and also have hydrophobic/ oleophilic nature for improvement of oil sorption capacity and recovery capability plays significant role in oil spill treatment [5]. Polyurethane (P.U) is considered as a natural material with certain properties such as low density, high porosity, easily fabrication, open-cell, and industrial production. However, it usually absorbs both oils and water [6,7]. P.U tended to exhibit its elevated oil sorption capacity with oil of low viscosity. With more viscous

Peer review under responsibility of Egyptian Petroleum Research Institute. ⇑ Corresponding author. E-mail address: [email protected] (M. Keshawy).

oils, the pores in P.U were obstructed, they resulted in decreasing the oil swelling capacity [8,9]. Polyurethane foam possesses excessive porosity which is ideal for oil uptake capacity however not favorable for transporting of the foam and keeping oil in the foam. Therefore, it is very important to find a route to improve the sorption capacity of P.U foam without decreasing its density [10]. Till now considerable earlier studies has been devoted to improve the effect of the cellular shape, foam density and surface modification on oil sorption of polyurethane foam. Few research have compelled at the improvement of the effect of polyurethane smooth phase shape at the oil absorption potential [11,12]. Recently various studies are centered on the functionalization of P.U pores’ surfaces which in turn have good effect on oil swelling capacity [13]. One of the major routes for the surface modification of the P.U foams is their functionalization with organic materials that have hydrophobic and/or oleophilic character, which offer the proper wetting properties to the foams for an efficient oilwater separation process. Such functionalization including silanization of the P.U foams, grafting and/or polymerization of oleophilic and hydrophobic organic monomers on the pores’ surfaces, modification by using micro and nanoparticles to increase the roughness and improving hydrophobicity and selectivity. Treatments with nanoparticles connected on the foams were obtained by the combination with organic compounds that supplied extra properties and/or participated to the stabilization of the nanoparticles’ attachment on the foam’s surface [14,15]. It’s far recognized that alkyl acrylate monomers with a long-chain alkyl group have a good affinity to oil or nonpolar solvents. Therefore, their polymers might also have an excellent swelling

https://doi.org/10.1016/j.ejpe.2019.11.001 1110-0621/Ó 2019 Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

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M. Keshawy et al. / Egyptian Journal of Petroleum xxx (xxxx) xxx

character in the oil [16,17]. In this work, we explore the chemical surface modification to P.U foam surface using acrylate monomer/nanomagnetite, aiming to allow extensive surface modification with acrylates molecules strongly coated to P.U surfaces in presence of crosslinker and nanomagnetite to increase their hydrophobic/oleophilic character and hence to improve their performance as oil sorbent. The reasons for incorporation of magnetite is to maximize the benefits from high surface area and magnetic power which in turn improve the swelling capacity and applicability. The produced P.U coated foam was characterized by various physicochemical tools and evaluated in light and heavy oil 2. Experimental 2.1. Materials Poly urethane foam (P.U) (slice to 1.5 cm  1.5 cm  1.5 cm before being utilized) collected from P.U foam waste, Egypt. Hexadcene (HD), nanomagnetite, laurylmethacrylate (LM), Benzoyl peroxide (BPO), Divinyl Benzene (DVB), 1,1,1-trimethylolpropane trimethacrylate (TPT) were purchased from Sigma Aldrich Co. Methanol, toluene from Scharlab S.L. Petroleum diesel and crude oil was obtained from Petrobel (Egypt). 2.2. Synthesis of hexadcene (HD)/laurylmethacrylate (LM) coated poly urethane foam P.U cubes was firstly washed with deionized water and methanol and dried under oven for 3 hrs at 70 °C. The reaction was kept running in a 250 ml three-necked flask equipped with nitrogen inlet, thermometer and reflux condenser. A defined weight of BPO initiator was dissolved in 50 ml toluene then mixtures of LM or HD or LM/HD monomer with different molar ratios and various crosslinker concentrations with varies % of either DVB or TPT was added to the flask with stirring under N2 at 80 °C for 3hrs. after that the P.U cubes was immersed in the flask solution for several

minutes to soak up the mixture, then removed from the solution and the cubes was transferred to an oven at 100 °C and kept at this temperature for12 h. 2.3. Synthesis of hexadecene (HD)-laurylmethacrylate (LM)nanomagnetite coated Poly urethane foam P.U coated HD-LM-magnetite was prepared using the previous procedure by addition the reaction mixture then adding different concentration of magnetite 0.5,1,2, 4 wt%. The P.U cubes was put to soak up the reaction mixture then kept at oven under 100 °C for 12 hrs. The constituents and designation of the synthesized coated Poly urethane (P.U) using different molar ratios of LM or HD monomer and various crosslinker concentration of either DVB or TPT and various contents of nanomagnetite are shown in Table 1. 2.4. Characterizations The surface morphology of coated P.U foams was examined by using SEM Model Quanta 250 FEG with accelerating voltage 30 K. V., FEI Company, Netherlands. The amorphous structure and incorporation of nanoparticles are confirmed using XRD which performed by using PANalytical X’Pert PRO diffractometer with Cu Ka = 1.5418 Å over the angular range from 5° to 80°. Thermal properties were determined using thermogravimetric analysis (TGA) [Q 600 SDT simultaneous DSC-TGA], and the samples were heated from 25 °C to 600 °C in N2 flow at a heating rate 10° C/minutes. 2.5. Sorption capacity test and regeneration The oil sorption capacity of P.U coated fibers was measured by weighing method according to ASTMF72699: as mentioned in our previous work [3,17]. Selected samples was used to investigate the effect of applying an external magnetic field to study the recovery of crude oil with the prepared magnetic materials.

Table 1 Designations and soluble fractions for polyurethane/hexadecane-lauryl methacrylate (P.U/HD-LM) coated copolymers. Composition of (PU/HD-LM)

Designation

DVB

TPT

Magnetite

SF%

100/0–0 50/0–50

P.U P.U/LM

0 wt% –

0 wt% 0 wt%

wt% wt% wt% wt% wt%

6.3 17.8 16.4 15.4 14.2 21.7 20.8 19.5 18.4 27.2 23.6 19.9 16.3 12.8

10/45–45 30/35–35 50/25–25 70/15–15 90/5–5

P.U/HD-LM P.U/HD-LM P.U/HD-LM P.U/HD-LM P.U/HD-LM

0 wt% 1 1.5 2 2.5 1 1.5 2 2.5 1 wt% 1 wt% 1 wt% 1 wt% 1 wt%

10/45–45

P.U/HD-LM

1 wt%

–

0.5 wt% 1 wt% 2 wt% 4 wt%

27.0 27.1 27.3 27.5

50/50

P.U/LM

–

1 1.5 2 2.5

0

16.6 15.2 13.4 12.6

50/50

P.U/HD

–

1 1.5 2 2.5

0

20.1 18.6 18.4 17.0

50/50–0

P.U/HD

– –

0 wt%

– – – – 1 wt%

0 0 0 0 0

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

M. Keshawy et al. / Egyptian Journal of Petroleum xxx (xxxx) xxx

3. Result and discussion P.U foams was recently used as a kind of porous oil sorbent materials for their low cost and elevated porosity that reach up to 95% leading to high oil sorption capacities. The pristine P.U foams absorbing both water and oil without any selectivity proving an amphiphilic surfaces, it’s must be modified by hydrophobic copolymers to be oil sorbent and water repellent. In this respect, acrylates monomers laurylmethacrylate (LM), and hexadecene (HD) were used to make surface modification for P.U foams and provide it with oleophylic, hydrophobic characteristics.

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3.1.2. XRD analysis of P.U coated foams: The data of X-ray diffraction of each magnetic nanoparticle, P.U coated copolymer nanomagnetite and P.U coated copolymer shown in Fig. 2(a–c) respectively indicates that the high amorphous structure of P.U/HD-LM10/45–45 and P.U/HD-LM10/45–45 2% Nano compared to linear diffractions of magnetic nanoparticles. The diffraction peaks of P.U/HD-LM10/45–45 located at 2h (25°– 40°) are very weak, indicating amorphous structure. On the other hand the incorporation of magnetite in (P.U/HD-LM10/45–45 2% Nano) lead to the appearance of magnetite diffraction peaks at at 2h ~ (15° and 40°) and they are strong and intense peak indicating the incorporation of high crystalline structure of magnetic nanoparticles.

3.1. Characterizations of P.U coated foams 3.1.1. Surface morphology of P.U coated foams The P.U coated foams surface was examined by SEM study the effect of copolymer composition and magnetite on the porosity of P.U foams. The micrographs also show the presence of thin cellular wall films within the foams, which may enhance its surface area, possibly further aiding oil sorption. The results of SEM analysis explained that the nanoparticles of all prepared samples have particle sizes below 20 nm and distributed over all surface of the sample compared to P.U coated copolymer without nanoparticle as seen in Fig. 1(a and b). The particles were generally spherical in the shape. However it can be supposed that the size distribution for all samples is rather wide. It can be seen that the P.U have porous network structure. In case of P.U coated copolymers with magnetic nanoparticles, the images in Fig. 1(b) shows the formation of nanostructures all over the P.U surfaces.

3.1.3. TGA analysis of P.U coated fibers The thermal gravimetrical analysis (TGA) of a) P.U, b) P.U/LM 50/50c) P.U/HD 50/50 d) P.U/HD-LM 10/45–45 and e) P.U/HD-LM 10/45–45 2% Nano respectively crosslinked by 1 wt% DVB are demonstrated in Fig. 3 The curve clears that, the initial degradation temperature of P.U is nearly 300 °C; the thermal stability of the P.U increases by alkyl chain length and by increasing copolymer alkyls moieties and increase by incorporating magnetic nanoparticle contents as for example 2 wt%. This may be attributed to the excellent heat resistance and machinability of 45HD-45LM copolymer and P. U/HD-LM 10/45–45 2% magnetic nano particle copolymers incorporated to polyurethane foam networks. The excellent thermal stability was noticed in P.U/HD-LM10/45–45 2%Nano Fig. 3(e) due to the incorporation of magnetite with elevating thermal stability, subsequently increase thermal and mechanical stability of magnetic coated P.U. In addition, the new degradation peaks in P.U

Fig. 1. SEM micrograph for a) P.U/HD-LM10/45–45 b) P.U/HD-LM10/45–45 2%Nano crosslinked by 1 wt% DVB.

Fig. 2. Demonstrates the X-ray diffraction (XRD) of a) nanoparticle, b) P.U/HD-LM10/45–45 and c) P.U/HD-LM10/45–45 2%Nano respectively crosslinked by 1 wt% DVB.

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

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Fig. 3. Demonstrates the thermal gravimetrical analysis (TGA) of a) P.U, b) P.U/LM50/50 c) P.U/HD 50/50 d) P.U/HD-LM10/45–45 and e) P.U/HD-LM10/45–45 2%Nano respectively crosslinked by 1 wt% DVB.

coated composites had been obviously determined at 400–460 °C due to the decomposition of waste polyurethane chains foam [18]. 3.2. Soluble fractions Soluble fractions of the prepared materials were determined and listed in Table 1 as described in previous works [19,20]. The data in Table 1 show the variation of SF% upon using different concentrations of LM/HD monomer ratios of different alkyl chains moieties at the same crosslinker content. In other words, the decrease of LM/HD contents display a reduction in SF% this decrease likely due to more promising structure for linking upon using extra alkyl chains moieties. This means that a pendants chain affects linking efficacy and thus SF%. The reduced SF% upon decreased alkyl chains moieties attributed to more steric conformations. Moreover, SF% was affected by amount and type of crosslinker, SF% for 1% TPT demonstrated less linking tool than 2.5% TPT. This referred to that the elevated crosslinker concentration decrease the probability of side reactions, which influence the linking activity. DVB shows the same behaviors concerning its quantity in each sample. Generally, the ideal concentrations of crosslinker with super absorbents and high swelling abilities are about 0.5–1 wt%. On the other hand, coated foams linked with various TPT contents show reduced SF% values with respect to those linked with DVB. This action reveals more efficacy of TPT than DVB attributed to existence of phenyl moieties in DVB allow it to enter in linking action of coated structure more readily than TPT due to more hydrophobicity [21]. Finally it is clear from Table 1 that the nanoparticles concentrations not affected on soluble fraction values.

mer. It is clear from the curves that Q increases by increasing comonomer concentrations reaching maximum at 90% ratio (45% LM to 45%HD). This can attributed to the reactivity ratios of acrylate monomers with DVB and TPT crosslinker and also to the hydrophobicity of the alkyl acrylate polymers which increased with increasing their contents with PU foam. The effect of nanoparticles concentrations namely 0.5, 1, 2 or 4 wt% of total weight added to P.U coated copolymers with 90% ratio (45% LM to 45% HD) using 1% DVB crosslinker in diesel sorption are represented in Fig. 5. The data reveals that the diesel sorption increase by increasing nanoparticles concentrations reached maximum 125 g/g at 2 wt% this is may be due to the huge surface area produced by introducing magnetic nanoparticles to coated polyurethane foam waste chains which give higher swelling of the polymeric network [22]. The maximum crude oil sorption attained by 10%P.U /45%HD/45%LM/ 2% Nanomagenetite crosslinked by 1% DVB was 115.88 g/g. This decreases due to viscosity variance between diesel and crude oil where crude oil with its high viscosity relative to diesel cannot simply diffuse from outside surface of samples into inside networks. Also, the higher viscosity of crude oil can cause opposed actions: reduced sorption during the permeation through inside of network and improved sorption during the oil is well stick to the compounds [23]. On the other hand the sample that gave the highest Qmax (P.U/HD-LM 10/45–45 2% magnetite & 1 wt% DVB) was subjected to an external magnetic field to study the effect of magnetic power on the oil recovery, we noticed that the Qmax increasing to 132.4 & 125.1 in diesel and crude oil respectively. This indicated that the use of magnetic power in oil recovery improve the efficiency and swelling capacity of the prepared magnetic materials.

3.3. Swelling behavior of P.U coated fibers

3.4. Effect of crosslinker type and concentration on absorption kinetics:

Diesel absorbencies (Qmax) of P.U coated either by different weight ratios LM or HD in P.U and diesel at room temperature (25 °C) using 1% DVB crosslinker for example at different immersion times are shown in Fig. 4a. All curves data shows increased with increasing soaking time till 75 min. On the other hand Fig. 4b shows swelling behavior of P.U coated copolymers with various weight ratios of LM/HD at 1% DVB crosslinkers in diesel oil. These Figures confirmed that the oil absorbency increase with growing immersion time and attains its maximum (Q) at times ranging among 60 min and 90 min based on the ratio of comono-

The effect of crosslinker content on absorption kinetics of prepared coated P.U foam crosslinked by either crosslinkers DVB or TPT immersed in 10% crude oil for example is present in Table 2. The data show that all TPT crosslinked coated samples demonstrated lower oil sorption than the DVB crosslinked samples, this may be attributed to formation of more dense network via using hexafunction TPT crosslinking agent compared to tetrafunction DVB crosslinker. It can be detected that, Qmax and Q values decrease with increasing either crosslinkers concentrations from 0.5% to 2% in all samples. The increment in the amount of the

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

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Fig. 4. Swelling behavior using 1 wt% of DVB for (a) P.U coated by either LM or HD (b) P.U coated with various weight ratios of LM/HD in diesel oil.

Fig. 5. The effect of magnetite nanoparticles concentrations 0.5, 1, 2 or 4 wt%, with magnetic recovery to PU coated copolymers with 90% ratio (45% LM to 45%HD) using 1% DVB crosslinker in diesel.

crosslinking agent forms denser network of the polymer [23] i.e., restricted relaxation of the polymeric chain [24]. Swelling kinetics of the obtained coated samples was determined according to Yao and Zhou [25], the swelling kinetic of the investigated coated waste was studied. The swelling parameters were determined and listed in Table 2. Table 2 shows Qmax, Q, equilibrium diesel or crude oil (EDC) or (ECC), characteristic time required for the swelling (T) and swelling kinetic constant (k) for the prepared samples by either DVB or TPT. Qmax values were discussed previously in swelling behavior section. The data of Q show the same trend as Qmax as it is about 2/3 of Qmax. Regarding EDC and EOC for the prepared samples both characters increase with increasing alkyl chains length of the coated used. They also show higher values upon using high contents of magnetic nano and with increasing the alkyl hydrophobic functionality [26]. The ability of the swelled P.U foam to undergo several cycles of swelling and deswelling is shown in Fig. 6. In this respect the swelling behavior of 10 wt% P.U coated copolymers with 90% ratio of (45 wt% LM to 45 wt% HD) using 1 wt% DVB crosslinkers in both diesel and crude

oil, at 2 wt% magnetic nanoparticles, was selected as a representative sample. After the first swelling cycle the P.U coated sample was immersed in ethanol, then lifted and drained. After that the sample was taken out and weighed to the next cycle and so on. We are able to see that after the primary cycle the gel did not attain the original swollen state but that in all of the following cycles it swelled back to its previous swollen state. This indicates that a minor quantity of the soluble fraction stay in the crosslinked gels which could have leached out upon deswelling, minimize the degree of consecutive swelling cycles [19]. 3.5. Network parameters The parameters for the network of treated foam were measured and obtained from measurements of swelling tests on diesel using equations (provided in details through our previous works) [27– 30] and listed in Table (3). Foam densities (qp) represent values less than unity that confirms their floatation on surfaces’ application.

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

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Table 2 Absorption and swelling parameters of polyurethane/hexadecane-lauryl methacrylate (P.U/HD-LM) coated copolymers at 25 °c in crude oil. Xerogel composition

Designation

Crosslinker content

Nano magnetite Content

10/45–45 30/35–35 50/25–25 50/50

P.U/HD-LM P.U/HD-LM P.U/HD-LM P.U/LM

50/50

P.U/HD

70/15–15 90/5–5 10/45–45

P.U/HD-LM P.U/HD-LM P.U/HD-LM

1 1 1 1 1.5 2 2.5 1 1.5 2 2.5 1 1 1

0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 1 2 4

Qmax (g/g)

Q (g/g)

T (h)

K (h-1)

ECC

DVB

TPT

DVB

TPT

DVB

TPT

DVB

TPT

DVB

TPT

105.5 99.4 81.3 91.2 88 82.4 84.7 96.4 93.1 90.2 88.1 55.1 51.8 91.2 110 115.88 115.8

– – – 90.2 86.55 80.4 78.7 92.4 88.1 82.2 80.1 – – – – – –

66.68 62.82 51.38 57.64 55.62 52.08 53.53 60.92 58.84 57.01 55.68 34.82 32.74 57.64 69.52 73.24 73.19

– – – 57.01 54.70 50.81 49.74 58.40 55.68 51.95 50.62 – – – – – –

0.38 0.35 0.35 0.35 0.37 0.33 0.31 0.35 0.36 0.34 0.32 0.36 0.30 0.35 0.34 0.32 0.30

– – – 0.36 0.35 0.34 0.33 0.37 0.36 0.35 0.33 – – – – – –

2.63 2.86 2.86 2.86 2.74 3.03 3.22 2.86 2.78 2.94 3.12 2.78 3.33 2.86 2.94 3.12 3.33

– – – 2.78 2.86 2.94 3.03 2.70 2.78 2.86 3.03 – – – – – –

99.05 98.99 98.77 98.90 98.86 98.79 98.82 98.96 98.93 98.89 98.86 98.19 98.07 98.90 98.90 99.09 99.14

– – – 98.89 98.84 98.76 98.73 98.92 98.86 98.78 98.75 – – – – – –

140 120 100 80

Diesel

60

Crude

40

20 0 0

2

4

6

8

10

12

14

16

Fig. 6. Deswelling of PU coated copolymers with 90% ratio (45% LM to 45%HD) using 1% DVB crosslinker and 2% nano particles in diesel or crude oil.

The v values for the prepared treated waste foam (Table 3), consider the free energy alterations that resulted from mixing and serves as a function of temperature as well as concentration [30]. v values of all tested samples absorbed in diesel turned out to be ranging from 0.30 to 0.39 (Table 3). This showed a promising result representing a good interaction between polymers with the tested solvents. Compared with different types of crosslinks, the DVB results have showed a slightly lower v values compared to TPT. The hydrophobic nature of DVB might be the reason why this action attributed. Crosslink density me and Mc values (Table 3) which are inversely proportional showed a significant affected by both the type and the concentration of cross linkers polymer structures. TPT gives in general higher me for all of the concentrations concerning DVB. This may be due to the resemblance of chemical structures of alkyl acrylates and TPT i.e. better inclusion. On the other hand, the values of Mc are reduced while using TPT rather than DVB and while using higher concentrations of one of the crosslinkers. The modulus GT values for P.U/HD-LM in diesel are represented in Table 3. Elastic modulus decreases with increasing HD-LM amount and by increasing nanoparticles concentrations through coated structures. In addition, GT values increase with increasing TPT or DVD concentrations. This may be ascribed to creation of denser linkage upon using higher TPT or DVD amounts. GT values for P.U/HD-LM samples linked with TPT are higher than those linked with DVB. This actions decrease elasticity upon using (TPT) with regard to (DVB).

4. Conclusions  SF values increase with increasing alkyl moieties (HD-LM) concentration in P.U composition  the SF% for crosslinked coated polyurethane is decreased when crosslinker content increased from 0.5 wt% to 2 wt%  Diesel and crude oil sorption increase by increasing nanoparticles concentrations in 10P.U/(45HD-45LM) – nano magnetite composition reached maximum at 2 wt% nanoparticles 132.4 g/g for diesel and 125.1 g/g for crude oil.  Oil-swelling capacities of the crosslinked coated polyurethane were increased by reducing crosslinking agent concentration and polyurethane content.  Swelling rate constant for the coated polyurethane crosslinked by DVB is higher than that crosslinked by TPT  The data of MC for the coated polyurethane by both DVB and TPT crosslinkers is in the order DVB > TPT.  GT and me values for the coated polyurethane waste by TPT are lower than that crosslinked by DVB.

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001

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Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.ejpe.2019.11.001.

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Please cite this article as: M. Keshawy, R. K. Farag and A. Gaffer, Egyptian crude oil sorbent based on coated polyurethane foam waste, Egyptian Journal of Petroleum, https://doi.org/10.1016/j.ejpe.2019.11.001