Crude Oil Cleanup Research Articles

Green and Scalable Fabrication of Durable Foam Composites with Asymmetric Wettability by an Emulsion Spray-Coating Method for Photothermally Induced Crude Oil Cleanup

Green and Scalable Fabrication of Durable Foam Composites with Asymmetric Wettability by an Emulsion Spray-Coating Method for Photothermally Induced Crude Oil Cleanup

Improved degradation of petroleum hydrocarbons by co-culture of fungi and biosurfactant-producing bacteria

Microbial remediation has proven to be an effective technique for the cleanup of crude-oil contaminated sites. However, limited information exists on the dynamics involved in defined co-cultures of biosurfactant-producing bacteria and fungi in bioremediation processes. In this study, a fungal strain (Scedosporium sp. ZYY) capable of degrading petroleum hydrocarbons was isolated and co-cultured with biosurfactant-producing bacteria (Acinetobacter sp. Y2) to investigate their combined effect on crude-oil degradation. Results showed that the surface tension of the co-culture decreased from 63.12 to 47.58 mN m−1, indicating the secretion of biosurfactants in the culture. Meanwhile, the degradation rate of total petroleum hydrocarbon increased from 23.36% to 58.61% at the end of the 7-d incubation period. In addition, gas chromatography – mass spectrometry analysis showed a significant (P < 0.05) degradation from 3789.27 mg/L to 940.33 mg/L for n-alkanes and 1667.33 μg/L to 661.5 μg/L for polycyclic aromatic hydrocarbons. Moreover, RT-qPCR results revealed the high expression of alkB and CYP52 genes by Acinetobacter sp. Y2 and Scedosporium sp. ZYY respectively in the co-culture, which corelated positively (P < 0.01) with n-alkane removal. Finally, microbial growth assay which corresponded with Fluorescein diacetate hydrolysis activity, highlighted the synergistic behavior of both strains in tackling the crude oil. Findings in this study suggest that the combination of fungal strain and biosurfactant-producing bacteria effectively enhances the degradation of petroleum hydrocarbons, which could shed new light on the improvement of bioremediation strategies.

Superhydrophobic, electrically conductive and multifunctional polymer foam composite for chemical vapor detection and crude oil cleanup

The leakage of chemicals (either vapors or liquids) severely threatens the environment and even people’s health. It remains a great challenge to develop multifunctional and durable materials that can not only detect the chemical vapors but also clean up the liquid chemicals especially high viscous crude oil. Here, a superhydrophobic and conductive foam composite (SCFC) is prepared by decorating carbon black nanoparticles (CBNPs) onto the skeleton of the pre-swollen polymer foam under the assistance of ultrasonication. The CBNPs are firmly embedded onto the skeleton surface, exhibiting a strong interfacial adhesion and hence excellent surface stability and durability. The SCFC possesses stable vapor sensing behavior and can detect various chemical vapors with a low detection limit and good cycling performance. When used for oil/water separation, the SCFC has large oil adsorption capacity for different oils with excellent reusability. Also, the outstanding photo-thermal conversion performance of the SCFC can be used to significantly reduce the oil viscosity and hence realize efficient cleanup of the crude oil. The multifunctional SCFC has promising applications in the field of environment protection, flexible electronics, etc.

Easily Fabricated Low-Energy Consumption Joule-Heated Superhydrophobic Foam for Fast Cleanup of Viscous Crude Oil Spills.

Effective cleanup of viscous crude oil spills remains a persistent and crippling challenge. Herein, this work presents a Joule-heated superhydrophobic flower-like Cu8(PO3OH)2(PO4)4·7H2O-coated copper foam (SHB-CF@CP) for rapid cleanup of viscous crude oil spills via a facile strategy. The SHB-CF@CP shows outstanding water repellency and excellent stability of hydrophobicity in harsh environments. Due to the high electrical conductivity and thermal conductivity, it requires lower power energy consumption (less than 1 V of voltage input) to raise the temperature significantly, which dramatically reduces the viscosity of crude oil (from ∼2 × 105 to ∼60 mPa s) and then increases the oil absorption rate, effectively avoiding the poor mobility and ineffective absorption of viscous crude oil. Notably, the SHB-CF@CP can achieve continuous and quick cleanup of crude oil under in situ pumping force. The high-performance Joule-heated SHB-CF@CP sorbent with a strong porous skeleton, corrosion resistance, and low predicted operational costs holds a promise of promoting its practical applications in the cleanup of intractable and large-area viscous oil spills.

Bioremediation treatment improves water quality for Nile tilapia ("{"Oreochromis niloticus"}") under crude oil pollution

BACKGROUND AND AIM: Despite favorable publicity of bioremediation as an affordable technology for cleanup of crude oil, public concerns on ecological safety in the presence of residual oil remain a global challenge. In this study, effects of crude oil exposure at sublethal concentration (0.25% v/v) and bioremediation treatment were investigated on histology and biochemical parameters of organs (gills, liver, kidney, and brain) of juvenile Nile tilapia (

Monoaromatic Hydrocarbon Bioremediation of Hydrocarbon-contaminated Soil Using HBB5 Biosurfactant Produced by Pseudomonas xiamenensis

Biodegradation of benzene toluene ethylbenzene and xylenes (BTEX) is a slow and complex process. However, many microbial organisms have been shown to possess the capacity to biodegrade various components of a hydrocarbon. This study was aimed at investigating the role of biosurfactant on soil polluted with these monoaromatics. Samples were collected and analyzed using standard techniques. The biodegradation set up was carried out using five earthen pots; each containing unpolluted soil, polluted soil alone, polluted soil + poultry wastes, polluted soil + HBB5 biosurfactant and polluted soil + poultry wastes + HBB5 biosurfactant. The biodegradation of BTEX were periodically monitored every seven days for 28 days using gas chromatograph-mass spectrometer coupled with head space (GC-MS-HS). The respective initial and final concentrations of BTEX (ppm) were as follows; 0.7936 and 0.2063, 0.9733 and 0.0231, 0.9526 and &lt;0.0001, 0.9241 and &lt;0.0001 with degradation efficiencies of 74.0%, 97.6%, 100% and 100% for polluted soil alone, polluted soil + poultry wastes, polluted soil + HBB5 biosurfactant and polluted soil + poultry wastes + HBB5 biosurfactant respectively. The microbial counts increased greatly, and the concentrations of the limiting nutrients reduced during the experimental period. The effective treatments for bioremediation increased in the following order: polluted soil alone &lt; polluted soil + poultry waste &lt; polluted soil + HBB5 biosurfactant &lt; polluted soil + poultry waste + HBB5 biosurfactant. Results clearly showed that application of HBB5 biosurfactant only or in combination with poultry wastes has the ability to degrade ethylbenzene and xylenes (BTEX) and thus, can be employed in the clean-up of crude oil contaminated soil.

Mechanically robust, solar-driven, and degradable lignin-based polyurethane adsorbent for efficient crude oil spill remediation

Rapid cleanup of crude oil spills is a worldwide challenge because heavy oil components (>103 mPa·s) are difficult for removal by conventional porous oil sorbents due to their inherent high viscosities. In this work, we took advantage of the photothermal effect by using sunlight as the energy source to heat heavy oil components for significantly reducing their viscosities to achieve a fast crude oil cleanup. A carbon nanotube (CNT) modified lignin-based polyurethane foam was fabricated as a photothermal sorbent that exhibited outstanding adsorption capacity for heavy oil. The modified foam achieved nearly full sunlight absorption (97%) with its surface temperature reaching up to 90.3 °C within 500 s owing to the excellent photothermal effect of CNTs. The resulting solar heating effectively reduced the viscosity of the heavy oil, which enabled the modified foam to quickly adsorb more than six times (6.34 ± 0.27 g/g) of its weight of crude oil within 6 min under one sun illumination (1.00KW/m2). Meanwhile, the lignin-based foam adsorbents were degradable in alkaline environments and CNTs can be recovered from the same condition. They could reach a degradation efficiency of 88.03% in 2 mol/L NaOH aqueous solution at 80 °C for 10 h, and the degradation rate was as high as 6.25 mg/h. Given the novel structural design, excellent environmental friendliness, rapid oil adsorption rate, and high oil adsorption capacity, this work provides a promising solution for addressing catastrophic large-area viscous crude oil spills.

Versatile and cost-efficient cleanup of viscous crude oil by an elastic carbon sorbent from direct pyrolysis of a melamine foam

Carbon sponge with photothermal and Joule thermal properties was prepared by pyrolysis of melamine sponge. The significantly decreased viscosity of crude oil from heating enables a rapid and continuous crude oil cleanup under all weather conditions.

Carbon nanofiber based superhydrophobic foam composite for high performance oil/water separation

Oil spill has now been a serious environmental issue, threatening the aquatic ecosystems and even human living environment. It is still challenging to develop absorbents for efficient oil/water emulsion separation and clean-up of viscous crude oil. Here, we propose a facile method to fabricate flexible and superhydrophobic foam composites for high efficiency oil/water separation under different complex environment. Carbon nanofibers (CNFs) with a hollow structure are decorated uniformly onto the skeleton of the polydimethylsiloxane (PDMS) foam with a strong interfacial adhesion. CNFs could not only enhance the surface roughness and thus the hydrophobicity but also be served as numerous capillary tubes, improving the oil adsorption and oil/water separation performance. More importantly, the CNFs network with a strong light absorption endows the foam with superior photo-thermal conversion capability. The obtained foam composite possesses excellent corrosion resistance and can adsorb various kinds of oil with different densities. The foam composite is able to separate the oil from the emulsion with a relatively high separation efficiency. The material surface temperature is able to quickly increase under the light irradiation, which can significantly reduce the oil viscosity and hence achieve the rapid clean-up of the crude oil floating on water surface.

Bioremediation treatment improves water quality for Nile tilapia (Oreochromis niloticus) under crude oil pollution.

Despite favorable publicity of bioremediation as an affordable technology for cleanup of crude oil, public concerns on ecological safety in the presence of residual oil remain a global challenge. In this study, effects of crude oil exposure at sublethal concentration (0.25% v/v) and bioremediation treatment were investigated on histology and biochemical parameters of organs (gills, liver, kidney, and brain) of juvenile Nile tilapia (Oreochromis niloticus). Ten percent (10%) of mixed bacterial culture was used for bioaugmentation treatment. Ninety juvenile fish were used for study, and experiments were carried out in triplicates for three different groups. Malondialdehyde (MDA), an index of lipid peroxidation, was assayed as biomarker for oxidative stress. Activities of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)), level of non-enzymatic antioxidant (reduced glutathione (GSH)), and activity of brain acetylcholinesterase (AChE) were assayed in selected fish organs as markers for environmental stressor. Histological examination of fish organs was done for all groups. Results of treated groups were compared with those of the control. Levels of MDA significantly increased with significant inhibition of antioxidant enzyme activities in the polluted group. Activities of SOD, CAT, and AChE and levels of GSH in fish organs in the bioaugmentation group were similar to results obtained in the control. Remarkably, the bioaugmentation group showed minimal or no lesions which suggested the efficacy of bioremediation technique in alleviating crude oil toxicity and preserving normal physiology of fish. This study provides deeper insights into the ecosafety of bioremediation treatment and can be extrapolated to other species of fish.

Low optical dosage heating-reduced viscosity for fast and large-scale cleanup of spilled crude oil by reduced graphene oxide melamine nanocomposite adsorbents

Heating under low solar radiation intensity is demonstrated to facilitate the cleaning of crude oil by the hydrophobic nanocomposite adsorbents of reduced graphene oxide (RGO) melamine sponge (MS@RGO) foams. The heat generated by the irradiation reduces the viscosity of the crude oil, and consequently increases the oil-diffusion coefficient of the pores of the MS@RGO foams and speeds up the oil-sorption rate. Even under a solar radiation intensity as low as 2 kW m−2, the temperature of crude oil rapidly rises to 68 °C or higher within 10 min. It only takes 29 s to completely absorb 6 g of crude oil at 60 °C by three tiny pieces of MS@RGO foam. This work makes better use of the excellent photothermal conversion characteristics of crude oil, and its photothermal conversion mechanism under simulated solar radiation is also discussed. This methodology can be adopted to clean up viscous crude oil or extract other chemicals effectively at a large scale, and provides a complete solution for the cleanup of crude oil in the sea or on the beach for actual engineering applications.

Reduced graphene oxide composites and its real-life application potential for in-situ crude oil removal

Crude oil pollution can cause severe and long-term ecological damage and oil cleanup has become a worldwide challenge. Conventional treatment strategies like in-situ burning, manual skimmer and bioremediation were labor-intensive and time-consuming. The high viscosity of crude oil also posed difficulty for traditional absorbents. Herein, to address these limitations, we designed and fabricated a floating absorbent that was comprised of reduced graphene oxide (RGO), melamine sponge (MS), and a 3D-printed mounting platform. Through a facile one-pot hydrothermal method, graphene oxide (GO) was simultaneously reduced to RGO and loaded in MS (RGO-MS). The resulted RGO-MS composites possess desirable hydrophobicity/oleophilicity for oil absorption with a water contact angle of 122°. The effective light-to-heat conversion allowed the RGO-MS composite to absorb approximately 95 times its own weight of crude oil within 12 min under light irradiation. A 3D-printed mounting platform for RGO-MS composites was further fabricated to improve its applicability and allow easy retrieval. Taking advantages of the RGO’s hydrophobicity/oleophilicity and photothermal property, the floating ability of MS, this study demonstrated the real-life applicability of RGO-MS composites for in-situ crude oil cleanup.

Solar activated crude oil cleanup using net-shape-formed ultralight graphene tiles

Accidental crude oil spills over a large water surface can wreck environmental and economic havoc. To mitigate such disasters, timely intervention to contain and recover oil before it spreads is critical. Standard lipophilic sorbents do not work because crude oil is too viscous to flow into them, especially in cold weather. This has led to the proposal of using graphene foam, also an excellent lipophilic sorbent, since it is a conductor and can be electrically heated, thus rendering the crude fluid enough to absorb. Yet wiring, powering and electrically heating any mass over a large area in high seas is clearly a challenge. Here we present a solution using a solar-activated graphene tile: within seconds upon exposure to daylight, it heats up and absorbs, eventually filling crude oil into 74 % of its own volume. It may be further coated by a lipophilic oil-permeating thermal insulation to become a light-absorbing, heat-retaining and oil-absorbing black hole. Capable of withstanding high heat up to 600 °C, tiles can be rejuvenated by ridding themselves of adsorbed oil in self-combustion, allowing even a small supply of tiles to last and contain oil spill for some time. The reusable tile is made by pyrolyzing a poly(vinylidene chloride) foam of an identical size and shape, obtaining a density of 16 kg m−3 and a strength of 11.7 kPa. Upon emergency, tiles initially installed as ultralight load-supporting constructs on oil-production platforms and crude-transport vessels become immediately available for repeated oil absorbing at 41 times their own weight. Therefore, they can provide the crucial first-response kit for mitigating oil-spill disasters.

Biodegradation of Total Petroleum Hydrocarbon by Molecularly Identified Bacteria Isolated From an Oilfield Wastewater in Nigeria

Biodegradation of petroleum hydrocarbon is a complex process that depends on the nature and on the amount of the hydrocarbon present. Many microbial organisms have been shown to possess the capacity to biodegrade various components of hydrocarbon. Hence this study was aimed at assessing the potential of bacterial species isolated from oilfield wastewater to biodegrade total petroleum hydrocarbon in crude oil. Oilfield wastewater was collected from an onshore oil production platform. Standard procedures were observed during collection and microbiological analysis of wastewater samples. Bacteria isolated were identified using conventional and molecular methods. The biodegradation set up was done using six conical flasks containing basal medium of mineral salt broth and crude oil as the source of energy for growth. Bacteria isolated were identified as Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus and Lysinibacillus species. Flasks of experimental set ups were inoculated with 1ml of individual isolate and mixed culture except the control. The biodegradation of TPH were periodically monitored for 35 days using Gas Chromatography (GC). Total viable counts (CFU/ML) obtained during the experiment ranged from 0-1.8×105, 1.65×105 - 3.2×106, 1.90×106 -1.28×107, 1.52×106 – 8.9×106, 1.13×106 – 1.48×107, 3.4×106 – 2.19×107 in control, Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus, Lysinibacillus species and the mixed culture treatment options respectively. The initial concentration of TPH at day 1 was 3241.47mg/l. At the end of the experiment (day 35), control, Acinetobacter species, Enterobacter hormaechei, Myroides odaratimimus, Lysinibacillus speccies and the mixed culture treatment options recorded final concentration of 2823.33, 363.72, 383.44, 284.55, 472.70 and 212.21mg/l respectively. Highest percentage removal of 93.5% was observed in the mixed culture while the least of 12.9% was observed in the control; individual species showed significant reduction in TPH with different capability. Results showed that bacteria isolated from oilfield wastewater have the ability to degrade total petroleum hydrocarbon (TPH) and can be used in the clean-up of crude oil contaminated area.

Harnessing Solar-Driven Photothermal Effect toward the Water-Energy Nexus.

Producing affordable freshwater has been considered as a great societal challenge, and most conventional desalination technologies are usually accompanied with large energy consumption and thus struggle with the trade‐off between water and energy, i.e., the water–energy nexus. In recent decades, the fast development of state‐of‐the‐art photothermal materials has injected new vitality into the field of freshwater production, which can effectively harness abundant and clean solar energy via the photothermal effect to fulfill the blue dream of low‐energy water purification/harvesting, so as to reconcile the water–energy nexus. Driven by the opportunities offered by photothermal materials, tremendous effort has been made to exploit diverse photothermal‐assisted water purification/harvesting technologies. At this stage, it is imperative and important to review the recent progress and shed light on the future trend in this multidisciplinary field. Here, a brief introduction of the fundamental mechanism and design principle of photothermal materials is presented, and the emerging photothermal applications such as photothermal‐assisted water evaporation, photothermal‐assisted membrane distillation, photothermal‐assisted crude oil cleanup, photothermal‐enhanced photocatalysis, and photothermal‐assisted water harvesting from air are summarized. Finally, the unsolved challenges and future perspectives in this field are emphasized. It is envisioned that this work will help arouse future research efforts to boost the development of solar‐driven low‐energy water purification/harvesting.

Solar-heated graphene sponge for high-efficiency clean-up of viscous crude oil spill

A solar-driven self-heated sponge was developed as a novel sorbent to achieve fast collection of crude oil from spills by taking advantage of light-to-heat conversion to significantly reduce oil viscosity. The sorbent was fabricated via facile dip-coating reduced graphene oxide on a commercial melamine sponge. The photothermal effect of sorbent on absorption of crude oil was investigated through infrared thermal imaging, permeating behavior of crude oil droplet and absorption-recovery of crude oil. The results indicated that the graphene sponge revealed an outstanding light-to-heat conversion capability and stability with almost full absorption (∼98%) of sunlight. The surface temperature spontaneously increased to as high as 89 °C under one sun simulated irradiation (1.0 kW/m2) at room temperature (30 °C), which subsequently reduced the in situ viscosity of the crude oil by over two orders of magnitude. As a result, the absorption time was reduced by approximately 86% for a solar-heating sponge under one sun illumination compared with that of the sponge without light illumination. In addition, the consecutive recovery rate for pumping-driven crude oil clean-up from seawater under one sun illumination was 12 times faster than that of the sponge without light illumination. The proposed solar responsive sorbent design represents a sustainable approach to address the problem of remediation of viscous crude oil spills.

Application of lightweight expanded clay aggregate as sorbent for crude oil cleanup

Application of lightweight expanded clay aggregate as sorbent for crude oil cleanup

Enumeration and Identification of Microbial Load in Oil Spilled Soil Remediated using Eudrilus eugeniae

The scope of this study was to enumerate and identify microorganisms present in crude oil polluted soil before and after remediation with <i>Eudrilus eugeniae</i> using conventional method for enumeration and molecular tools (ITS 1 and ITS 4 primers) for identification. A crude oil polluted soil from Khana Local Government of Rivers State Nigeria and also soil from botanical garden of the University of Lagos were used. These soil samples were measured in four different concentrations (25%, 50%, 75% and 100%). Each of these concentrations was experimental setup of addition of substrate alone, <i>E. eugeniae</i> and substrate and E. eugeniae alone. These setups were made in triplicate amounting to a total of thirty six experimental setups. Enumeration of microbial load was done before and after addition of each of the content of the experimental setups using conventional method and then identification of microbes was done using molecular tools. The result shows total heterotrophic fungi was 2.9 x 104 cfu/m/g, while the total heterotrophic bacteria was 4.4 x 105 cfu/m/g before remediation. After remediation, total heterotrophic fungi was 1.6 x 105 cfu/m/g while total heterotrophic bacteria was 5.0 x 104 cfu/m/g. This shows that microorganisms were present in the soil before and after remediation. The increase in number of microbes suggests a favorable condition for continuity of microbial life. Fungi such as <i>Trichoderma asperellum, Aspergillus flavus, Penicillum chrysogenum</i> and another strain of <i>Aspergillus flavus</i> were identified. The bacteria sequencing failed suspected to be due to primers used or error with sequencing plates. In conclusion, the results of this study confirmed the presence of microorganisms in crude oil polluted soils. The enumeration and identification of the bacteria and fungi in this experiment will help to enhance in situ clean-up of crude oil polluted soil.<div><br></div>

Influence of a Dispersant on the Types and Growth of Microbial Hydrocarbon Degraders in a Crude Oil-contaminated Medium.

Background:Dispersants are first order response strategies for oil spill cleanup in an aquatic environment. However, their effects on the biodegradation capacity of indigenous hydrocarbon-degrading microorganisms are little known.Objectives:The influence of a dispersant (DS/TT/066) on the type(s) and growth of hydrocarbon-degrading bacteria (HDB) and hydrocarbon-degrading fungi (HDF) in a crude oil-contaminated medium (water) was investigated in the laboratory for 28 days.Methods:The experiment was set up in duplicates with the first set containing Forcados light crude oil (FLCO) alone in water while the other was a mixture of FLCO and DS/TT/066 (ratio 9:1 v/v). Identification and enumeration of HDB and HDF were conducted according to standard methods. Total petroleum hydrocarbons (TPH) in the test media was analyzed using a gas chromatography/flame ionization detector.Results:The results showed that HDB identified in the FLCO alone included Pseudomonas aeruginosa (day 0), Proteus vulgaris (day 14), P. aeruginosa and Kliebsiella pneumoniae (day 28). However, in the mixture, Escherichia coli was identified on day 14 in addition to the other species observed in FLCO alone. HDF identified in FLCO alone were Candida krusei and Candida albicans (days 0 and 14), Trichosporon cutaneum and C. albicans (day 28). In the mixture, HDF identified were C. albicans (day 0), C. albicans and Aspergillus spp. (days 14 and 28)″ Furthermore, the mixture enhanced the growth of HDBF (average counts: 32.5 × 107 and 225 × 106 cfu/mL) compared to FLCO alone (17.5 × 107 and 17.5 × 106 cfu/mL) by day 14 respectively. Total petroleum hydrocarbon reduction was highest (85%) in the mixture compared to 5% in FLCO alone by day 14.Conclusions:The study demonstrated the biodegradation efficiency of E. coli, P. vulgaris (bacteria), C. albicans and Aspergillus spp. (fungi) in a crude oil-contaminated aquatic environment in conjunction with dispersant use. Further studies in the field are recommended in order to explore their potential for rapid and large scale crude oil clean-up operations.

Coiled Plant Tendril Bioinspired Fabrication of Helical Porous Microfibers for Crude Oil Cleanup.

Fabrication of the helical fibers with sheath/core structure comprising 3D interconnected porous polystyrene (PS) and ductile polyvinylidene fluoride is inspired by coiled plant tendril. The key innovation point applied in this study is to produce a helical porous system based on sheath/core structure that can come into being a huge storage space in the sorption process for crude oil. More importantly, the mechanical properties confirm to have a more excellent improvement than that of the initial PS fibers, which make it become a possible candidate for the large‐area sorption and reuse of crude oil from the ocean or industry. The bioinspired fabricating strategy opens a significant avenue between the coaxial electrospinning and crude oil contamination cleanup. It is also expected that the unique structure can make it a promising candidate for applications in energy conversion, tissue engineering, and intelligent devices.