Oil Desorption Research Articles

Evaluation of Oil Desorption from Shale and Sandstone by Surfactant Solutions with Implication to Oily Drillcuttings Decontamination

In this paper, batch experiments of shale/sandstone aqueous systems were conducted to evaluate desorption of spiked oil from shale and sandstone using surfactant solutions. The desorption experimental study was designed to determine if selected surfactants in aqueous solutions with varying pH, initial oil on shale/sandstone, surfactant concentrations, surfactant type, solid/liquid ratio, with and without sonication and at different contact time could enhance the desorption of spiked oil (Sarapar147) from pre-spiked shale and sandstone. The experiments tested the influence of the selected variables in batch experiments. The early screening results obtained for sandstone and shale show that sandstone are very much easier to clean than shales. Furthermore, the desorption efficiencies was lower for water compared to surfactant solutions particularly for sandstones. Nevertheless, ultrasound was able to improve the desorption efficiencies for sandstone washings but not for shale washings. In the other hand, the results of the full factorial experiments showed that the variations of solution pH, mechanical interruption by ultrasound, and prolonged desorption times did not significantly improve the desorption process. These results give strong evidence to the existence of a considerable and irreversibly bound fraction of oil to shale.

Evaluation of Oil Desorption from Shale and Sandstone by Surfactant Solutions with Implication to Oily Drillcuttings Decontamination

In this paper, batch experiments of shale/sandstone aqueous systems were conducted to evaluate desorption of spiked oil from shale and sandstone using surfactant solutions. The desorption experimental study was designed to determine if selected surfactants in aqueous solutions with varying pH, initial oil on shale/sandstone, surfactant concentrations, surfactant type, solid/liquid ratio, with and without sonication and at different contact time could enhance the desorption of spiked oil (Sarapar147) from pre-spiked shale and sandstone. The experiments tested the influence of the selected variables in batch experiments. The early screening results obtained for sandstone and shale show that sandstone are very much easier to clean than shales. Furthermore, the desorption efficiencies was lower for water compared to surfactant solutions particularly for sandstones. Nevertheless, ultrasound was able to improve the desorption efficiencies for sandstone washings but not for shale washings. In the other hand, the results of the full factorial experiments showed that the variations of solution pH, mechanical interruption by ultrasound, and prolonged desorption times did not significantly improve the desorption process. These results give strong evidence to the existence of a considerable and irreversibly bound fraction of oil to shale.

Wettability alteration in carbonate and sandstone rocks due to low salinity surfactant flooding

Commonly, desorption of crude oil from rock surfaces accomplished by the exposure to the decreasing salt concentrations of NaCl, Na2SO4, MgCl2 and CaCl2 solutions. However, adsorption and desorption of crude oil are the functions of several attributing factors at undoubtedly low salinity brine solutions. For silica surfaces, both rock and oil possess negative charges during low salinity injection that leads to the electrical double layer expansion and electrostatic repulsion between them. For carbonate rocks, rock dissolution and negatively charged surface at higher pH could be regarded as the driving forces for oil desorption. Thus, adsorption/desorption studies of different oils over silica and carbonate rocks while considering salinity, ion composition and aging of the rocks would be sufficient to alter the wettability of the rocks. In the present paper, the effect of saline water containing surfactant has been discussed on the performance of enhanced oil recovery (EOR). Wettability alteration triggered by the change in interfacial tension (IFT) between crude oil and low salinity surfactant (LSS) is known to be the main factor regarding EOR processes. However, wettability depends on several factors, namely, multiple ion exchange (MIE), interfacial elasticity modulus, cation bridging, acid/base numbers of oil, rock composition and structure, ratio of divalent/monovalent (M2+/M+) cations in the formation brine, aging time, the status of zeta potential, surfactant structure and concentration, pH of the medium, T & P of reservoir, permeability and pressure drop change. Therefore, we thoroughly examine the microscopic mechanisms of LSS flooding via studying individual aforementioned factors that influence the contact angle change in sandstone and carbonate rocks.

Inspection for desorption behavior and desorption mechanism of oily sludge by thermodynamics and kinetics analysis

Abstract In this study, the solvent extraction experiment was investigated to probe the desorption behaviors and desorption mechanism of oily sludge with n-heptane as solvent. Desorption isotherms were analyzed and fitted by Langmuir, Freundlich and Redlich-Peterson equations at different temperatures. Then, the thermodynamics parameters such as standard free energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) were calculated. Based on thermodynamics analysis and calculation, oil was proved to exist in the form of the colloidal dispersion system. In addition, the kinetics was fitted by the pseudo-first-order kinetic model and the pseudo-second-order kinetic model. Kinetic studies showed that desorption process of asphaltenes was restrained severely due to strong interactions between sludge and asphaltenes, and resins played a crucial role in asphaltenes desorption. The desorption mechanism was discussed based on experimental results and further analysis. The solvent effect and carry-over effect were deemed to be crucial to oil desorption. The carry-over effect is generated from electrostatic interactions, hydrogen bonds, electron donor-acceptor and π-π interactions, which was also the essence of asphaltenes desorption.

Computer simulations of underwater oil adhesion of self-assembled monolayers on Au (111)

ABSTRACTMolecular dynamics and steered molecular dynamics (SMD) simulations are used to investigate the underwater adhesive forces of 1, 2-dichloroethane (DCE) on ionic and non-ionic self-assembled monolayers (SAMs) grafted on Au (111). The non-ionic SAMs containing hydroxyl group include ethanolamine-terminated SAM (ETA-SAM), dopamine-terminated SAM (DOPA-SAM), hydroxyl-terminated SAM (OH-SAM) and oligo(ethylene glycol)-terminated SAM (OEG-SAM); the ionic SAMs contain mixed-charged zwitterionic SAM and zwitterionic phosphorylcholine-terminated SAM . Simulation results show that the order of underwater oleophobicity of SAMs is OEG-SAM < ETA-SAM < OH-SAM < DOPA-SAM < < , while the order of underwater DCE oil droplet adhesion forces on different SAMs is < < ETA-SAM < DOPA-SAM < OH-SAM < OEG-SAM. The ionic SAMs show stronger underwater oleophobicity and lower oil adhesion than non-ionic SAMs. Generally, a more underwater oleophobic surface is less adhesive. The underwater oil droplet desorption behaviours on ionic and non-ionic SAMs are also different. With the oil droplet being pulled away from ionic SAMs, the oil contact lines gradually shortened and disappeared finally; whereas the oil contact lines on non-ionic SAMs almost kept an initial state even the main part of oil droplet separated from the SAMs. This work systematically proved that a zwitterionic surface was less underwater oil adhesive than a non-ionic surface and provided a new insight for their oil desorption behaviours. The above results will be helpful for the design of underwater oleophobic surfaces with tuneable adhesion.

Effect of Low Salinity on the Oil Desorption Efficiency from Calcite and Silica Surfaces

Low-salinity water flooding has been suggested to improve oil recovery in sandstone reservoirs. However, application in carbonate reservoirs is still controversial. In this work, a quartz crystal microbalance (QCM) was used to investigate the impact of the chemical composition of crude oils and crystal surfaces on the adsorption/desorption efficiency of oil components upon exposure to various salinity solutions to reveal the potential of enhancing oil recovery from carbonate reservoirs. The surface charge of carbonate rock is characterized by ζ potential measurements. For QCM-D measurements, Norwegian and North Sea crude oils with various acid numbers were used, while calcite and silica crystals were used to mimic carbonate and sandstone reservoirs. The results reveal that the amount of adsorption is correlated to the concentration of polar organic components present in the oil and the type of surface mineral. Subsequent desorption showed that low amounts of desorption are reported upon exposure to seawat...

Study on oil adsorption/desorption kinetics and polymer network parameters of poly(lauryl methacrylate-co-hydroxyethyl methacrylate)

In the present work, oil adsorption, desorption, and resorption of poly(lauryl methacrylate-co-hydroxyethyl methacrylate) P(LMA-co-HEMA) were evaluated with different oils by a gravimetric method. Adsorption kinetics were modeled using pseudo-first-order and pseudo-second-order equations. Polymer network parameters of P(LMA-co-HEMA) regarding average molecular weight (Mc) between two crosslink piontss can be calculated by oil absorbency at equilibrium (Q e ), the solubility parameter (δ) and polymer-solvent interaction parameter (χ) with Flory-Huggins relation. The results showed pseudo-second-order model has a better fit to the oil adsorption kinetic data The desorption can be analyzed by fitting a prediction of exponential-like decay to the deswelling curves. A typical oil desorption exhibited two stages: a burst release driven by concentration gradient, and a slow release controlled by diffusion and the elastic recovery of polymer networks. For reusability, the resorption behavior of P(LMA-co-HEMA) was also investigated. It was worth noting that oil resorption was faster than the first adsorption due to potential passages. Moreover, the adsorption capacity was not significantly changed after regeneration.

Desorption of hydrocarbon chains by association with ionic and nonionic surfactants under flow as a mechanism for enhanced oil recovery

The need to extract oil from wells where it is embedded on the surfaces of rocks has led to the development of new and improved enhanced oil recovery techniques. One of those is the injection of surfactants with water vapor, which promotes desorption of oil that can then be extracted using pumps, as the surfactants encapsulate the oil in foams. However, the mechanisms that lead to the optimal desorption of oil and the best type of surfactants to carry out desorption are not well known yet, which warrants the need to carry out basic research on this topic. In this work, we report non equilibrium dissipative particle dynamics simulations of model surfactants and oil molecules adsorbed on surfaces, with the purpose of studying the efficiency of the surfactants to desorb hydrocarbon chains, that are found adsorbed over flat surfaces. The model surfactants studied correspond to nonionic and cationic surfactants, and the hydrocarbon desorption is studied as a function of surfactant concentration under increasing Poiseuille flow. We obtain various hydrocarbon desorption isotherms for every model of surfactant proposed, under flow. Nonionic surfactants are found to be the most effective to desorb oil and the mechanisms that lead to this phenomenon are presented and discussed.

Diverse wettability of superoleophilicity and superoleophobicity for oil spill cleanup and recycling

The frequent marine oil spill accidents in nowadays has aroused great attention all over the world. Lots of superwetting absorption materials with 2D or 3D structures are fabricated to efficiently remove oil spill, but the desorption of the absorbed oil is more difficult. Oil contaminants adhere on the surface will decline the performance and reusability of the absorption materials. Discarding or burning them will bring secondary pollution. Faced with these problems, we prepared an oil extractor integrated by a superhydrophobic-superoleophilic stainless steels wire mesh and a 3D porous cellulose sponge with superhydrophilicity-superoleophilicity in air and superoleophobicity in water. The oil extractor can in situ collect oil spill no matter on the water or under the water. More importantly, it is good at underwater oil desorption, which ensure the recovery and reuse of oil, and meanwhile avoid the materials being fouled by oils. More than 85.5% of crude oil could be successfully discharged only in 2min when the oil-contaminated sponge was placed in water. The findings in this work not only put forward a new strategy for collection and reuse of various “oils”, but also offer a facile method to achieve a combination of two kinds of materials with diverse wettability.

Probing the essence of strong interaction in oily sludge with thermodynamic analysis

Abstract In this study, the oily sludge was extracted with toluene, naphthane, naphtha or petroleum ether as solvent to reveal the essential interaction in oily sludge through thermodynamic analysis method. The surface component activity (SCA) model was utilized to eliminate the particles accumulation effect (Cp-effect) in order to obtain evolutional Langmuir isotherm. The maximum adsorption capacity ( Γ o ) of oil and equilibrium constant (Keq) of desorption process was calculated from the slope and intercept of the linear fitted Langmuir isotherm. Hence, the thermodynamic functions, such as Gibbs free energy (△G), enthalpy change (△H) and entropy change (△S), were further determined from the results of Keq. The Fourier transform infrared spectroscopy (FT-IR) was applied to analyze the oily sludge. Strong interactions, such as O H⋯O hydrogen bond, between oil molecules and particles were eventually found to be the essential reason for preventing the oil desorption. The thermodynamic analysis method developed in this work also provided feasible guidance to improve the extraction efficiency for oily sludge.

Oil absorption and desorption by polypropylene fibers

Oil spill is a threat to the ecosystem, and there is a need for the development of highly efficient oil sorbents for environmental remediation. In this study, four different types of polypropylene fibers were evaluated for their oil absorbency and desorption characteristics. These fibers varied in their fineness and structural characteristics, i.e., hollow or solid. A modified ASTM methodology was used in the study to better represent the oil sorption capacity of a sorbent. To the best of our knowledge, this is the first study to present the effect of fiber fineness and structure on the oil desorption behavior of polypropylene fibers. Results showed that finer fibers had higher oil sorption capacity (g/g) than the coarser fibers. There was no statistical difference in the rate of desorption among the solid fibers; however, the hollow fiber had a statistically higher rate of desorption than the solid fibers.

Lemon essential oil desorption from polypropylene/talc nanocomposite films

A phenomenological analysis on desorption mechanism of lemon essential oil in semicrystalline polymer nanocomposites is performed. Films were made of polypropylene and talc nanoparticles obtained by blown extrusion were used as a case study due to the high complexity of sorption phenomena in such systems containing a semicrystalline polymer and nucleating particles. In this sense, a systematic analysis combining both morphological effects and intrinsic properties of each component was considered. Talc characteristics, e.g., morphology, surface chemistry, oil absorption properties, mean particle size and its distribution, and impurity presence, were considered in desorption analysis. Regarding semicrystalline matrix, morphological and crystalline changes induced by talc nanoparticles and processing were included in this study. Desorption of lemon essential oil from nanocomposite films with different talc concentrations (0, 1, and 5 wt%) which have distinctive and well characterized morphologies was evaluated through gravimetric and thermogravimetric analysis. Results show that polypropylene film has a desorption rate higher than nanocomposites containing 5 wt%, but lower than those with 1 wt% talc. This behavior is a consequence of the global crystallinity configuration changes produced by nanoparticle concentration and film obtaining process. It is revealed that simplified and conventional approaches that consider tortuosity as unique effect of particle presence in nanocomposite mass transport do not allow to comprehend the desorption mechanism involved in a complex system such as the semicrystalline polymer nanocomposites. The present study gives additional insight into the complex mechanism involved in desorption of strongly swelling oil in nanocomposite films based on semicrystalline polymers and mineral nucleating particles.

Release of Crude Oil from Silica and Calcium Carbonate Surfaces: On the Alternation of Surface and Molecular Forces by High- and Low-Salinity Aqueous Salt Solutions

Adsorption and desorption of a North Sea crude oil to silica and calcium carbonate surfaces were studied by a quartz crystal microbalance, while the bare surfaces and adsorbed oil layers were characterized by atomic force microscopy and contact angle measurements. Water contact angles were measured on the bare surfaces, surfaces with an adsorbed oil layer, and surfaces after being exposed to aqueous salt solutions. This showed that the silica surface became more hydrophobic after oil adsorption, while the wettability of the calcium carbonate surface was not significantly changed by adsorption of an oil layer. A surface energy component analysis based on the acid–base theory showed that oil adsorption on the surfaces depends upon apolar, acidic, and basic oil components of the crude oil and that the adsorbed oil components differ for adsorption to silica and calcium carbonate. Desorption of the crude oil was investigated by exposing the surfaces with an adsorbed oil layer to a series of NaCl and CaCl2 solu...

Online regeneration of PP/PEW oil‐sorbing fabrics at bypass sorption column in oily circulating cooling water system

AbstractThe bypass purification technology for separating the leaked oil in circulating cooling water is in the early stage of development. To achieve a continuous removal of oil, the online regeneration characteristics of oil‐sorbing fillers should be studied. Therefore, the effect of oil‐sorbing fillers, polypropylene/polyethylene wax fabrics, on the sorption of corrosion and scale inhibitors was evaluated primarily in this study. The regeneration efficiency of three regeneration methods and the effect of the rotating speed of centrifugal sorption column on the oil desorption performance were studied. Furthermore, the effects of regeneration interval for online centrifugal and replacement regenerations on the purification time were investigated. The results indicate that almost no corrosion and scale inhibitors were sorbed on polypropylene/polyethylene wax fabrics. The average efficiency of the centrifugal regeneration method was up to 95%. The oil desorption performance increased with the increase in the rotating speed of the centrifugal sorption column up to 18 rev/s, above which the performance did not change significantly. In the online centrifugal regeneration, the best regeneration interval was tn+1 = 1.2n, thus decreasing the regeneration time and effectively shortening the purification time. Compared with the online replacement regeneration, the online centrifugal regeneration saved approximately 700% fabrics. Copyright © 2016 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

A Robust Absorbent Material Based on Light‐Responsive Superhydrophobic Melamine Sponge for Oil Recovery

Advanced materials with intelligent switchable surfaces that can respond to external stimuli have encouraging application in oil/water separation and oil clean‐up. Herein, a facile method has been demonstrated to prepare a robust and superhydrophobic sponge by integrating the melamine‐formaldehyde (MF) sponge with light‐responsive spiropyran derivative via a radical copolymerization process, which shows the light‐controllable oil absorption and desorption property under light illumination. The key chemistry is that the MF sponge is first modified with vinyl for the copolymerization via a facile solution‐immersion process. Afterward, light‐responsive spiropyran methacrylate monomers are copolymerized with vinyl‐modified MF sponges to fabricate polymer‐MF sponge composites (denoted as SP‐MF sponge), resulting in the wettability conversion from amphiphilic to superhydrophobic with a water contact angle of 155.5°. The superhydrophobic MF sponge shows excellent selectivity and high absorption capacity for a range of oils and organic solvents from 70 to 154 times its own weight. More importantly, since the hydrophobic polymer of the SP‐MF sponge can be converted to hydrophilic under UV illumination, the wettability of SP‐MF sponge will change to hydrophilic, resulting in the light‐controlled oil desorption process. These findings offer a new responsive absorbent material and a new approach for oil recovery.

Oil desorption and recovery from cork sorbents

This study focuses on the recovery of sunflower oil from cork sorbents, namely of regranulated type, either by desorption using different eluents or by mechanical compression. Saturation of sorbents was carried out in pure oil medium. Elution with tap water, 0.1M H2SO4 and 10mM sodium dodecyl sulphate (SDS, anionic surfactant) solutions showed very low efficiency, below 10%. Slight improvement was achieved with 10mM hexadecyltrimethylammonium (HDTMA) bromide (cationic surfactant) and 0.1M NaOH solutions. The latter was the best performing desorbing solution with a recovery of 24±3%. Mechanical compression was evaluated at different operating pressures, compression time, number of compression cycles and cork sorbent mass loads. It was found that interrupted compression favours oil recovery when compared to continuous compression. The increase of the mass load led to the occurrence of a ‘pillow effect’ which caused increased recovery and protected the cork sorbents from structural damage. The effect of the operating pressure was less pronounced, but for a mass load of 10g the process was improved by increasing the pressure from 2 to 7bar.Finally, it was demonstrated that for 10g mass load, 7bar operating pressure, and a protocol of four 1-min compressions, a recovery efficiency of 67±1% was achieved and both the sorption capacity and recovery efficiency remained generally stable over 10 cycles.

Fabrication of a Self-Cleaning Surface via the Thermosensitive Copolymer Brush of P(NIPAAm-PEGMA).

Surface hydrophilicity and the inherent washing force are two crucial factors for constructing an underwater self-cleaning surface. Following this self-cleaning mechanism, we fabricated thermosensitive copolymer brushes of N-isopropylacrylamide (NIPAAm) and poly(ethylene glycol) methacrylate (PEGMA) on the polypropylene (PP) surface. Benefiting from the hydrophilic poly(ethylene glycol) (PEG) side chains, the copolymer brushes with the PEGMA content exceeding 5 mol % exhibited good surface hydrophilicity, whenever at temperatures below or above the lower critical solution temperatures (LCST). Hence their underwater oleophobicity was greatly improved with oil contact angles higher than 141° and oil adhesive forces lower than 20 μN. In addition, the sharp volume-phase transition feature was reserved in their copolymer backbones, as proved by the AFM result. Self-cleaning evaluation of the modified surfaces was performed by a simple temperature-change water cleaning method, after which only 0.2 wt % of oil residues remained on the brush surface of P(NIPAAm-5PEGMA) (with 5 mol % of PEGMA contents). The excellent self-cleaning capability is believed to be ascribed to its balanced surface features in hydrophilicity and the sharper volume-phase transition, when a hydrophilic surface can facilitate oil desorption and an intense conformation change of chain stretching and shrinking can offer the strong washing force to assist oil detachment. This study contributes to development of the underwater self-cleaning surface based on a hydrophilic surface with the chain motion.

Equilibrium partition of rapeseed oil between supercritical CO2 and prepressed rapeseed

The equilibrium partition of a vegetable extract between supercritical (SC) CO2 (fluid phase) and a vegetable substrate (solid phase) is commonly best-fitted in the mathematical simulation of extraction curves. The aim of this study was to develop and apply an experimental methodology to measure the equilibrium partition of rapeseed oil between SC CO2 and prepressed rapeseed. We measured and modelled sorption isotherm/isobar curves using a methodology that intersperses extraction (to reduce oil content) and equilibration (by recirculation of the SC CO2 phase) steps, with oil being sampled in each step. Oil desorption was a two-stage process; when rapeseed contains more than ∼70–80gkg−1 oil/substrate the SC CO2 phase gets saturated with oil (Cf=Csat), whereas when it contains less oil this is bound to the solid matrix in such a way that Cf dips below Csat. Increasing pressure from 22 to 28MPa at constant temperature (40°C) increases Cf. The effect of the increase in pressure is less pronounced when SC CO2 density is kept constant (857.1kg/m3) by simultaneously increasing temperature from 40 to 50°C. The heat of desorption of the oil is ∼100kJ/mol which suggests it is bound to the prepressed seed by van der Waals interaction forces. However experimental values in this region are uncertain due to propagation of uncertainties to estimate Cs.

Method for Determining the Amount of Crude Oil Desorbed from Silica and Aluminosilica Surfaces upon Exposure to Combined Low-Salinity Water and Surfactant Solutions

The desorption of crude oil components from silica and aluminosilicate surfaces upon exposure to low-salinity surfactant solutions was investigated by a quartz crystal microbalance (QCM). The study aimed at facilitating a better understanding of a hybrid enhanced oil recovery (EOR) process, where low-salinity water is combined with surfactant flooding. The measurements were carried out for various concentrations of two sulfonate surfactants: sodium dodecylbenzene sulfonate (SDBS) and sodium dioctylsulfosuccinate (AOT). A procedure for obtaining the oil desorption efficiency (ODE) was developed on the basis of measuring adsorption of surfactants onto the crystals. Generally, the ODE increased when the concentration of surfactants increased. Furthermore, the ODE was lower for aluminosilicate surfaces than for silica surfaces. Contact angle measurements showed wettability alteration toward more water-wet conditions for both crystal surfaces after exposure to low-salinity surfactant solutions.

Switchable fluorescent AIE-active nanoporous fibers for cyclic oil adsorption

A porous fiber of AIE-active PMMA fabricated through the electrospinning technique shows exceptional fluorescence. The green fluorescence of porous fibers can be switched off and on by the adsorption and desorption of silicon or bean oil.