Cross-linked poly(tetrahydrofuran) as promising sorbent for organic solvent/oil spill

Sustainable polyurethane for the remediation of oil spills: a review

Catastrophic oil spill is one of the major issues to the environment. Various methods have been used to treat oil spillage including in situ burning, the use of skimmers, dispersants, bioremediation, dispersing agents, oil sorbents, and biological agents. Application of oil sorbent is one of the effective solutions in oil spill clean-up. Polymers are sustainable extraordinary materials for the treatment of oil spillage due to their special physicochemical characteristics such as high porosity, good hydrophobicity, and reusability. Polymers are modified using suitable chemical reagents and their hydrophobicity is enhanced, making them suitable for oil spill clean-up. The present manuscript is an attempt to summarize the study of chemical modifications done on a polymer polyurethane (PU) for achieving the desirable properties, for efficient oil spill clean-up. A patent analysis has been carried out for the leading countries, top inventors, leading assignees, trends of patent publications, citation analysis, and summary of granted patents in the area of the use of a polymer Polyurethane (PU) for oil spill clean-up.

The preparation of CaCO3-polyalkoxysilane porous nanocomposites as effective sorbent for oil spill removal

The novel porous nanocomposite sorbent was synthesized by the condensation of the diol monomer with the alkoxysilane cross-linker at moderately high temperatures in the presence of nano-CaCO₃ particles. The structural, thermal, and morphological properties of the nanocomposite sorbents were determined by using Fourier transform infrared spectroscopy (FTIR), solid-state CPMAS ¹³C and ²⁹Si NMR, scanning electron microscope (SEM), and thermal gravimetric analysis (TGA). Adding nano-CaCO₃ to the network structure of the polymer not only provided pores to the sorbent but also enhanced its sorption capacity towards various oils and toxic organic solvents. The nanocomposite sorbent exhibited excellent absorption capacity for different toxic organic solvents and oils and great reusability for ten cycles. Moreover, the obtained sorbent material selectively absorbed organic liquids from the surface and bottom of the water without any capacity change owing to their hydrophobicity and oleophilicity. These features of the nanocomposite make it a potential sorbent for the cleaning of oils and oil derivative organic contaminants from the environment.

Removal of oils and organic solvents from wastewater through swelling of porous crosslinked poly(ethylene-co-vinyl acetate): Preparation of adsorbent and their oil removal efficiency

In this novel study, an attempt has been made to prepare porous crosslinked poly(ethylene-co-vinyl acetate) polymer (C-EVA). The porous C-EVA was prepared by grafting of maleic anhydride and cetyl alcohol onto the polymer backbone with addition of NaCl as porogen in the brabender mixture at 120 °C and 80 rpm. This was followed by leaching of NaCl with water extraction to generate a highly porous polymer structure which was evident from its SEM micrographs. The polymer was found to have excellent swelling capacity in various oils and organic solvents and showed good selective absorption capacity. The reusability of the synthesized polymer was studied and it was found that it could be reused for more than 30 absorption desorption cycles without undergoing much change in its absorption capacity. The cross-linked polymeric composite was further characterized by FTIR, TGA, XRD, and SEM.

Polyolefin-based electrospun fibrous matrices embedded with magnetic nanoparticles for effective removal of viscous oils

In this work, we present a poly (ethylene-co-1-octene)-based fibrous matrix prepared via electrospinning for highly efficient removal of viscous oils. The sorbent consisting of linear low density polyethylene (LLDPE) allows selective absorption of crude oil spills at the water surface without the need for additional isolation of the matrix prior to the refining process. Moreover, the high specific pore volume of the LLDPE sorbent with uniform fibrous morphology was shown to enable the sorbent reach 81.5 ± 5.9% of its equilibrium absorption capacity within 5 min. Furthermore, magnetic nanoparticles (MNP) are incorporated into each fiber comprising the matrix to facilitate the recovery process via external magnetic field without altering the intrinsic absorption capacity. We envision that these sorbents offer a sustainable route for the quick and thorough clean-up of spilled oil due to their high absorption capacity, fast absorption rate, ease of recovery, and absence of secondary waste.

Environmental friendly Polyacrylonitrile nanofiber mats encapsulated and coated with green algae mediated Titanium oxide nanoparticles for efficient oil spill adsorption

Oil spill causes extreme environmental damage, from aquatic life to seabirds, disrupting the entire ecosystem. Herein, we have synthesized high scale, economical and bio-compatible, green algae mediated Titanium oxide (TiO₂) nanoparticles and Polyacrylonitrile (PAN) nanofiber mats. We have studied the effect of encapsulation and coating of TiO₂ nanoparticles over nanofiber mats for highly efficient oil spill adsorption. TiO₂ encapsulated and coated PAN (TECP) nanofibers showed a maximum of 62.34 g g^-1 adsorption capacity of petroleum oil from the water surface. Moreover, the composite mats show maximum adsorption within 45 s for up to 5 repeated cycles. Further, it has been observed that the adsorption capacity has increased by increasing the weight of the composite nanofiber mats, which confirms its commercial applicability. Thus, this work provides rapid, large-scale, economical, bio-compatible, and highly effective adsorbents for oil spill cleaning and extraction over natural waterbodies.

Nature-Based Solutions for Restoring an Agricultural Area Contaminated by an Oil Spill

A feasibility study is presented for a bioremediation intervention to restore agricultural activity in a field hit by a diesel oil spill from an oil pipeline. The analysis of the real contaminated soil was conducted following two approaches. The first concerned the assessment of the biodegradative capacity of the indigenous microbial community through laboratory-scale experimentation with different treatments (natural attenuation, landfarming, landfarming + bioaugmentation). The second consisted of testing the effectiveness of phytoremediation with three plant species: Zea mays (corn), Lupinus albus (lupine) and Medicago sativa (alfalfa). With the first approach, after 180 days, the different treatments led to biodegradation percentages between 83 and 96% for linear hydrocarbons and between 76 and 83% for branched ones. In case of contamination by petroleum products, the main action of plants is to favor the degradation of hydrocarbons in the soil by stimulating microbial activity thanks to root exudates. The results obtained in this experiment confirm that the presence of plants favors a decrease in the hydrocarbon content, resulting in an improved degradation of up to 18% compared with non-vegetated soils. The addition of plant growth-promoting bacteria (PGPB) isolated from the contaminated soil also promoted the growth of the tested plants. In particular, an increase in biomass of over 50% was found for lupine. Finally, the metagenomic analysis of the contaminated soil allowed for evaluating the evolution of the composition of the microbial communities during the experimentation, with a focus on hydrocarbon- oxidizing bacteria.

Surface treated Phoenix sylvestris for bioadsorption of oil from aqueous solution: Isotherms and kinetic studies

Biosorption is a versatile technique of removing the oil spill - one of the major toxicants that causes water pollution, which threatens the ecological balance of the aquatic ecosystem. The proposed research aims in developing a viable adsorbent from discarded agricultural waste, Phoenix sylvestris, which was surface altered, assessed and utilised as a biosorbent for the effective removal of diesel from aqueous solution in batch adsorption trials. Waste palm leaves, Phoenix sylvestris (RPS)was physically (PMPS) and chemically modified (CMPS) to adsorb diesel in the emulsion. The synthesised materials were characterised by FTIR, SEM, and EDS, confirming a well-defined microporous structure consisting of ionisable groups. The studies indicated optimised conditions of 10 g, 4.5 g and 2 g of RPS, PMPS and CMPS respectively at 303K for an optimised adsorption time of 60 min. Freundlich isotherm agreed well with experimental data, and the kinetic mechanism claimed better results with RPS, PMPS and CMPS for Pseudo first-order model. The adsorbents could be reused five times without much loss of efficiency. From the performed studies, it can be inferred that good adsorption capacities at optimised conditions followed the order of CMPS > PMPS > RPS. Thermodynamic analysis proved the feasibility of such biosorption with exothermic nature predicting spontaneous attraction of oil components to the surface of PMPS and CMPS. Moreover, the density of the CMPS layer rendered proven results for such biosorption displaying a hyperbolic dependency assuring its efficacy. Hence, it can be concluded that the prepared adsorbent from Phoenix sylvestris, an agricultural waste, possess good adsorptive properties.

A Novel Graphite-Based Sorbent for Oil Spill Cleanup

The performance of an innovative material based on expanded graphite, Grafysorber^® G+ (Directa Plus), has been tested through laboratory, tank, and confinement tests for oil removal in case of an oil spill and water treatment. In addition to the ability to retain oil, the possibility of reusing this material after regeneration via squeezing was also evaluated. As a comparison, the same experimental tests were conducted using polypropylene flakes (PP), the material currently most used to deal with spill accidents. Oils with different chemical and physical properties were used, namely kerosene, diesel, and crude oil. From the laboratory tests, the capacity of Grafysorber^® G+ to retain oil was found to be directly proportional to the viscosity of the latter, with adsorption values ranging from 76.8 g/g for diesel to 50.8 g/g for kerosene, confirming the potential of the innovative material compared to the PP. Cyclical use tests have confirmed certain reusability of the material, even if its adsorbent capacity decreases significantly after the first cycle and continues to decrease in subsequent cycles, but a less marked manner. Finally, some considerations based on the adsorption capacities were found to suggest that the adoption of the new material is also economically preferable, resulting in savings of 20 to 40% per kg of hydrocarbon treated.

Coco Peat as Agricultural Waste Sorbent for Sustainable Diesel-Filter System

Oil spill incidents are hazardous and have prolonged damage to the marine environment. Management and spill clean-up procedures are practical and rapid, with several shortcomings. Coco peat (CP) and coco fibre (CF) are refined from coconut waste, and their abundance makes them desirable for diesel spillage treatment. Using a filter-based system, the selectivity of coco peat sorbent was tested using CP, CF and peat-fibre mix (CPM). CP exhibited maximal diesel sorption capacity with minimal seawater uptake, thus being selected for further optimisation analysis. The heat treatment considerably improved the sorption capacity and efficiency of diesel absorbed by CP, as supported by FTIR and VPSEM-EDX analysis. Conventional one-factor-at-a-time (OFAT) examined the performance of diesel sorption by CP under varying parameters, namely temperature, time of heating, packing density and diesel concentration. The significant factors were statistically evaluated using response surface methodology (RSM) via Plackett-Burman design (PB) and central composite design (CCD). Three significant (p < 0.05) factors (time, packing density and diesel concentration) were identified by PB and further analysed for interactions among the parameters. CCD predicted efficiency of diesel absorbed at 59.92% (71.90 mL) (initial diesel concentration of 30% v/v) and the experimental model validated the design with 59.17% (71.00 mL) diesel sorbed at the optimised conditions of 14.1 min of heating (200 °C) with packing density of 0.08 g/cm3 and 30% (v/v) of diesel concentration. The performance of CP in RSM (59.17%) was better than that in OFAT (58.33%). The discoveries imply that natural sorbent materials such as CP in oil spill clean-up operations can be advantageous and environmentally feasible. This study also demonstrated the diesel-filter system as a pilot study for the prospective up-scale application of oil spills.

Exploring the use of cellulose nanocrystal as surface-washing agent for oiled shoreline cleanup

Surface-washing agents are an option to enhance the removal of oil spilled or stranded on shorelines. The use of nanocellulose-based nanofluid as a surface-washing agent was studied by investigating its reactivity and effectiveness. Salinity was found to be the most influencial factor to facilitate oil removal with the nanofluids. Cations from salt can promote the adsorption of nanocellulose on the oil/water interface by reducing the surface charges. The experimental results revealed the nanocellulose could be effective at low concentrations but an excess of nanocellulose hindered oil removal due to an increase in fluid viscosity. A miscibility model was applied to verify this finding in a thermodynamics context. The biotoxicity tests showed that nanocellulose-based nanofluid did not have negative effects on algae growth and introducing nanocellulose into an oiled culture medium can actually mitigate the toxicity of the oil on algae. A comparison in removal efficiency with other surfactants demonstrated the potential value for shoreline cleanup due to the superior effectiveness of nanocellulose-based nanofluids. Overall, a nanocellulose has a high potential for application as a surface-washing agent for shoreline cleanup due to the low cost, low toxicity, and high efficiency.

A sustainable strategy for the remediation of oil/water separation using polybenzoxazine/stearic acid functionalized porous carbon

Fabrication of superhydrophobic and superoleophilic polybenzoxazine-stearic acid based melamine sponge for industrial oil/water pollution treatments.

A novel column fabrication approach for capillary gas chromatography via a cross-linked organogel network with high stability and inertness

A new column fabrication approach for capillary gas chromatography with high column selectivity, stability and inertness.

Assessment of Performance of Posidona oceanica (L.) as Biosorbent for Crude Oil-Spill Cleanup in Seawater

The marine environment is constantly at risk of pollution by hydrocarbon spills that requires its cleanup to protect the environment and human health. Posidonia oceanica (L.) (PO) beach balls, which are characteristic of the Mediterranean Sea and abundant on the beaches, are used as biosorbent to remove hydrocarbons from the sea. The impact of several factors such as oil concentration, time sorption, and weight sorbent was investigated to determine the oil and water sorption capacity for raw and milled P. oceanica fibers. The study of kinetic models for initial crude oil concentration of 2.5, 5, 8.8, 10, 15, 20, 30, and 40 g/L revealed that crude uptake followed the pseudo-first-order model while, for isotherm models, the crude uptake onto the P. oceanica tended to fit the Langmuir model. Experiments were performed according to two systems: a pure oil and pure water system and a mixed oil/water system. For the dry system (pure oil and pure water), the maximum oil and water sorption capacity of raw and milled fibers was found to be 5.5 g/g and 14 g/g for oil and 14.95 g/g and 15.84 g/g for water, respectively, whereas, in the mixed oil/water system, the maximum oil and water sorption capacity was estimated as 4.74 g/g, 12.80 g/g and 7.41 g/g, 8.31 g/g, respectively. The results showed that, in spite of their absorbency of a lot of water, the milled fibers with grain size ranging between 0.5 mm and 1 mm might be the relevant sorbent for the elimination of crude oil from seawater thanks to its efficient sorption capacity and low cost.

Enhanced Oil Spill Remediation by Adsorption with Interlinked Multilayered Graphene

The performances of an innovative material based on graphene multilayers in a 3D structure similar to expanded graphite, Grafysorber^® G+ (Directa Plus), have been tested via in field applications on a real contaminated site. Several experimental tests were performed using Grafysorber^® inside adsorbent devices (booms and pillows) to treat waters polluted by oil. The experimental campaign was carried out with the aim of comparing the performances of Grafysorber^® with those of polypropylene (PP), which is the material used worldwide in case of water oil spill clean-up activities. The results achieved have confirmed a considerably higher selective adsorption capacity of Grafysorber^® compared to PP, and configure the new material as a promising alternative to standard materials in enhancing oil spill remediation by selective adsorption.

Natural rubber/reduced-graphene oxide composite materials: Morphological and oil adsorption properties for treatment of oil spills

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Natural rubber/rGO composite foam was used as an oil sorbent.

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Addition of rGO enhanced the oil adsorption capacity and strength of NR sorbent foam.

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Inclusion of 0.5 phr rGO into NR increased the crude oil adsorption capacity to 17.04 g g⁻¹.

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Oil adsorption mechanism of the sorbent materials was proposed.

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Reusability of the NR/rGO sorbent was greater than 70% oil adsorption for 30 cycles.

A green sorbent material was fabricated through the simple addition of reduced graphene oxide (rGO) to natural rubber (NR) latex. The effect of rGO content in the NR foam on petroleum oil adsorption was investigated. The addition of rGO in NR increased the petroleum oil adsorption capacity of the resulting NR/rGO (NRG) composite foam (12–21 g g⁻¹) with respect to those of the pure NR foam (8–15 g g⁻¹) and a commercial sorbent (6–7 g g⁻¹). The adsorption capacity was optimal for 0.5 phr rGO (NRG-0.5). Further, the environmental conditions (temperature and waves) affected the oil adsorption capacity of the sorbent materials. The adsorption kinetics of the sorbent materials for crude AXL oil was best described with pseudo-second-order kinetics. The interparticle diffusion model revealed three steps whereas the adsorption isotherms approximated the Langmuir isotherms. Moreover, the oil adsorption mechanisms of the NR and NRG sorbent materials were compared to that of a commercial sorbent. The high elasticity of the NRG-0.5 composite foam improved not only the oil adsorption capacity but also the reusability of the sorbent material. The presence of rGO increased the strength of the NRG-0.5 compared to that of pure NR, which resulted in a high-performance and reusable material with an oil removal efficiency higher than 70% after 30 uses.

A functionalized nano-structured cellulosic sorbent aerogel for oil spill cleanup: Synthesis and characterization

A new synthesis strategy was adopted to convert cellulose to a biodegradable sorbent with properties of very high oil absorption and retention capacities, excellent oil-water selectivity, good mechanical strength and recycling ability. The sorbent in form of a hydrophobic/oleophilic nano-structured aerogel was prepared through functionalizing cotton cellulose with low surface energy moieties followed by dissolving and chemically cross-linking the product in an organic medium (DMSO), and freeze-drying. High absorption capacities of 40.7, 57.1, and 47.3 g/g were achieved for three different light crude oils at 25 °C which is comparable with most synthetic oil sorbents. Washburn's model was utilized to describe the wicking dynamics and fluid flow through the pores and to evaluate the effects of all important factors on the sorption process. Via comparing the experimental data with the predictions made by the model, it was revealed that unlike other cellulose-based oil sorbents reported in the literature, the swelling of fibrous network in the synthesized aerogel plays an important role in the absorption process besides the capillary pressure, resulting in a very good oil retention capacity and at the same time lowering the absorption rate, especially for viscose organic liquids.

Polybenzoxazine-Functionalized Melamine Sponges with Enhanced Selective Capillarity for Efficient Oil Spill Cleanup

Severe environmental and ecological issues arising from frequent oil spill accidents have been great worldwide concerns. Considering the abruptness, complex condition, and long-term perniciousness of the spilled oil, the development of economic and versatile materials to quickly remove oil contaminants, especially for oil with high viscosity from a large water body, is of significant importance but remains a big challenge. Herein, we demonstrated a facile strategy to fabricate a versatile hierarchical structured sponge with superhydrophobicity and powerful oil capillarity via the in situ polymerization of a novel phenolic resin (polybenzoxazine) composite open-cell sponges. The tunable hierarchical structures of the as-prepared sponge significantly improved its water repellence and oil capillarity; meanwhile, a plausible mechanism is also proposed. With the merits of high porosity, excellent water repellence, enhanced oil capillarity, and robust mechanical stability, the obtained sponge exhibited an intriguing oil spill cleanup performance with fast oil absorption speed, good recyclability, and high absorption capacity. Besides that, the modified sponge could also be utilized for the separation of oil/water mixture with individual phase and the surfactant-stabilized emulsion solely under the drive of gravity. The robust oil/water separation performance, low cost, and facile synthesis strategy make the resultant sponges a competitive material for the large-scale oil spill emergency remediation.

Superhydrophobic graphene-based sponge as a novel sorbent for crude oil removal under various environmental conditions

Mechanical recovery of oils using oil sorbents is one of the most important approaches to manage marine oil spills. However, the properties of the oils spilled into sea are influenced by external environmental conditions. In this study, we present a graphene-based (GB) sponge as a novel sorbent for crude oil removal and compare its performance with that of a commercial sorbent sheet under various environmental parameters. The GB sponge with excellent superhydrophobic and superoleophilic characteristics is demonstrated to be an efficient sorbent for crude oils, with high sorption capacity (up to 85-95 times its weight) and good reusability. The crude-oil-sorption capacity of our GB sponge is remarkably higher (about 4-5 times) than that of the commercial sheet and most other previously reported sponge sorbents. Moreover, several challenging environmental conditions were examined for their effects on the sorption performance, including the weathering time of oils, seawater temperature, and turbulence (wave effect). The results show that the viscosity of the oil increased with increasing weathering time or decreasing temperature; therefore, the sorption rate seemed to decrease with longer weathering times and lower temperatures. Turbulence can facilitate inner sorption and promote higher oil sorption. Our results indicate that the extent of the effects of weather and other environmental factors on crude oil should be considered in the assessment of the effective adsorption capacity and efficiency of sorbents. The present work also highlights the widespread potential applications of our GB sponge in marine spilled-oil cleanup and hydrophobic solvent removal.

Oil loving hydrophobic gels made from glycerol propoxylate: Efficient and reusable sorbents for oil spill clean-up

Glycerol propoxylate based oil loving sorbents were prepared through bulk polymerization, without using of an activator, initiator, or catalyst. Fourier transform infrared spectroscopy (FTIR), ¹³C and ²⁹Si CPMAS nuclear magnetic resonance (NMR), as well as elemental analysis and thermal gravimetric analysis (TGA) were operated in order to identify the structural and thermal features of sorbents. The synthesized gels were employed as absorbents for various organic solvents and oils. The swelling capacity, absorption-desorption kinetics, reusability, and selective removal from an oil/water mixture were also examined. To explore the effects of a crosslinker's concentration on oil absorption capacity, star type propoxylate monomers were reacted at different concentration of tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS) crosslinker; swelling capacity was calculated using dichloromethane as an organic solvent. Oil removal ability from the water surface is another important section contained within this article.

The electrospinning of the copolymer of styrene and butyl acrylate for its application as oil absorbent

Electrospun polystyrene materials have been employed as oil absorbents, but they have visible drawbacks such as poor strength at low temperature and unreliable integrity because of brittleness and insufficient cohesive force among fibers. Butyl acrylate can polymerize into flexible chains, and its polymer can be used as elastomer and adhesive material. Thereby it is possible to obtain the material that has better performance in comparison with electrospun polystyrene material through the electrospinning of the copolymer of styrene and butyl acrylate. In this work, a polymer was synthesized through suspension polymerization by using styrene and butyl acrylate as comonomers. The synthesis of the copolymer of styrene and butyl acrylate was verified through dissolution and hydrolysis experimental data; as well through nuclear magnetic resonance spectrometry. The viscous flow activation energy of the solution consisting of copolymer and N, N-dimethylformamide was determined via viscosity method and then adopted to establish the entanglement characteristics of butyl acrylate’s chain segments. Finally, in order to electrospin the copolymer solution into fibrous membrane, the effects of monomer feed ratio and spinning parameters were investigated. The prepared fibrous membrane was found to have a potential use as oil absorbent.