Selective Oil Absorption Research Articles

Superhydrophobic Graphene/Cellulose/Silica Aerogel with Hierarchical Structure as Superabsorbers for High Efficiency Selective Oil Absorption and Recovery

Carbon-based aerogels have been recognized as a promising 3D superabsorbent material for oil absorption due to their high absorption capacity. However, their selective absorption efficiency is limited because of their relatively low hydrophobicity. Here, we report the fabrication of a fluorinated hybrid aerogel (FHA) consisting of graphene oxide (GO), cellulose nanofibrils (CNFs), and silica nanoparticles by one-pot hydrothermal synthesis and subsequent freeze-drying and chemical vapor deposition modification. The CNFs in FHA prevented volume shrinkage, greatly reduced the bulk density, and increased the surface area, while the GO retained its mechanical strength and the free-standing characteristic of FHA. Silica particles and CNFs created hierarchical structures on pore walls, and the grafted fluorochains reduced the surface energy. The synergistic effect of the hierarchical structure and low surface energy contributed to the excellent superhydrophobicity (water contact angle of 157°) and water repellen...

Design and preparation of efficient, stable and superhydrophobic copper foam membrane for selective oil absorption and consecutive oil–water separation

It is extremely important and challenging to develop an effective device for the continuous separation and recovery of large-scale oil–water mixtures due to their contribution to ecological remediation and contamination control. In this work, a superhydrophobic copper foam with high oil–water separation efficiency was successfully fabricated, which could serve both as oil absorption material and oil–water separation membrane, by in situ self-sacrificial template method combining the subsequent steaming modification. The obtained characterization results present that copper foam possesses large pore structure, micro-/nanoscale two-tier surface roughness, high water contact angle (153.6°), and low sliding angle (4.5°). Experimental results show that as-prepared copper foam could not only rapidly absorb residual oil either on the water surface or underwater, but also separate a series of oils from water, like carbon tetrachloride, trichloromethane, methylbenzene, pump oil and diesel. Furthermore, the separation efficiencies of copper foam on trichloromethane-water and diesel-water mixture were maintained above 96.9% and 90.8% after 10 cycles, respectively. Additionally, as-prepared copper foam exhibits excellent corrosion resistant ability and superior hydrophobic stability. The facile, low-cost and controllable strategy presented herein has a bright future in oil–water separation, and also can be further expanded to prepare various anti-corrosion, self-cleaning and water-proof sport materials.

Hybridization of Al2O3 microspheres and acrylic ester resins as a synergistic absorbent for selective oil and organic solvent absorption

In this study, we have focused on the synthesis, characterization, and oil absorption properties of Al2O3 microspheres/acrylic ester resin (AER) hybrids. The Al2O3 microspheres are prepared by a combined hydrothermal and sintering processes, followed by surface modification with silane coupling agent (KH 570). The Al2O3 microspheres/AER hybrids with a rough surface are synthesized by a microwave polymerization route by using modified Al2O3 microspheres as modifiers. In this hybrid materials system, the Al2O3 microspheres with porous structures may provide fast oil absorption due to the low oils absorption energy and short diffusion lengths. The resin hybrids exhibited reversible oils and organic solvents adsorption with maximum absorption capacities up to 29.85 g/g. This study suggests potential environmental advantage in using metal oxide microspheres in improving the oil absorption properties of oil‐absorbing resins as absorbents for recovering oil and organic solvent from water.

Magnetically driven superhydrophobic silica sponge decorated with hierarchical cobalt nanoparticles for selective oil absorption and oil/water separation

Three-dimensional superhydrophobic/superoleophilic materials (3D-HOMs) with remote controllability are highly desirable for water remediation. Herein, a new monolithic silica sponge decorated with hierarchical cobalt (Co) nanoparticles that fulfils almost all major requirements and applications for water remediation was fabricated by self-assembly electrospinning, controlled particle precipitation, and subsequent surface coating. Attributing to the continuous silica fibers and the hierarchical Co microstructures, the modified silica sponge (MSS) possesses excellent superhydrophobicity and oil selectivity, low bulk density (49 mg/cm3), high surface area (8.7 m2/g) and absorption capacity (45–91-fold weight gain), ultrahigh thermal resistance (tolerance to liquid nitrogen and combustion), flexibility, deformability, durability, and remote controllability through magnetic field manipulation. Moreover, simply compacting MSS can easily enhance its separation efficiency by bringing the interior structures to the contacting interfaces, which solves the performance deterioration issue over time for most 3D-HOMs. With all of these satisfactory properties, MSSs can be used as both durable magnetic superabsorbers and efficient oil/water separation filters with a long life span.

Correction to “Pressure-Sensitive and Conductive Carbon Aerogels from Poplars Catkins for Selective Oil Absorption and Oil/Water Separation”

Correction to “Pressure-Sensitive and Conductive Carbon Aerogels from Poplars Catkins for Selective Oil Absorption and Oil/Water Separation”

Simple and green fabrication of recyclable magnetic highly hydrophobic sorbents derived from waste orange peels for removal of oil and organic solvents from water surface

This study presents the preparation and characterization of natural waste material (orange peel) derived low cost, bio-based, recyclable, highly hydrophobic/superoleophilic magnetic sorbents to treat environmental pollution caused by oils and organic contaminants from water. Orange peels were dried, powdered and converted into magnetic and highly hydrophobic/superoleophilic sorbents by the incorporation of Fe3O4 nanoparticles using co-precipitation approach and subsequently modifying with low surface energy polydimethylsiloxane (non-fluorinated hydrophobic reagent) layers. SEM, EDS, XRD, FTIR, XPS, TGA, VSM and contact angle measurements analysis were used for characterization of the developed materials. The as-prepared sorbents exhibit strong magnetic behavior with saturation magnetization (Ms) value of 14.9 emu/g, excellent hydrophobicity with water contact angle of 149.2° and very high capacity for the selective absorption of various oils and organic solvents from oil contaminated water. It has high absorption capacity up to 5.11 and 6.90 times its original weight for diesel oil and engine oil respectively, along with high recyclability of more than eight cycles and the advantage of magnetic separation from water surface after absorption of oils. Thus, the orange peel waste derived absorbent with magnetic and high hydrophobic properties is a promising alternative for the capture of oil and organic pollutants from water.

Pressure-Sensitive and Conductive Carbon Aerogels from Poplars Catkins for Selective Oil Absorption and Oil/Water Separation

Multifunctional carbon aerogels that are both highly compressible and conductive have broad potential applications in the range of sound insulator, sensor, oil absorption, and electronics. However, the preparation of such carbon aerogels has been proven to be very challenging. Here, we report fabrication of pressure-sensitive and conductive (PSC) carbon aerogels by pyrolysis of cellulose aerogels composed of poplars catkin (PC) microfibers with a tubular structure. The wet PC gels can be dried directly in an oven without any deformation, in marked contrast to the brittle nature of traditional carbon aerogels. The resultant PSC aerogels exhibit ultralow density (4.3 mg cm-3), high compressibility (80%), high electrical conductivity (0.47 S cm-1), and high absorbency (80-161 g g-1) for oils and organic liquids. The PSC aerogels have potential applications in various fields such as elastomeric conductors, absorption of oils from water and oil/water separation, as the PSC aerogels feature simple preparation process with low-cost biomass as the precursor.

Hydrophobic Spongy Attapulgite for Absorption of Organics and Oils from Water

A new strategy of separation and selective absorption of organics or oils from water by using natural clay‐derived absorbent was demonstrated in our experiments. Spongy attapulgite (ATP) with mesoporous structure (average pore diameter of 10.75 nm and a BET surface area of 63 m2 g‐1) was successfully synthesized by thermolysis of ATP/polymers nanocomposites. Followed by treatment with polytetrafluoroethylene (PTFE) and polydimethylsiloxane (PDMS), the wettability of the spongy ATP can be tailored to be strong hydrophobic to water while superoleophilic to oil, which was also confirmed by X‐ray photoelectron spectroscopy. Due to its mesoporous structure and excellent hydrophobicity, the as‐resulted strong hydrophobic and superoleophilic spongy ATP shows good selectivity and absorption performance for a wide series of organic solvents and oils, which makes it the promising candidate for various applications, including oil spills cleanup, water treatment, liquid‐liquid separation and so on.

Polycaprolactone-based scaffold for oil-selective sorption and improvement of bacteria activity for bioremediation of polluted water: Porous PCL system obtained by leaching melt mixed PCL/PEG/NaCl composites: Oil uptake performance and bioremediation efficiency

A novel floatable and biodegradable sponge for the selective absorption of oil from water and potentially useful as cell carrier for bioremediation treatments was prepared in polycaprolactone (PCL). The eco-friendly process for fabricating the PCL sponge does not involve either synthetic routes or organic solvents, thus minimizing environmental hazard. In particular, the 3D porous materials have been prepared by mixing in the melt the polymer matrix with two water-soluble porogen agents (NaCl and PEG) and thereafter leaching the obtained PCL/NaCl/PEG composites in water. The PCL sponges here proposed are capable to remove different types of oily pollutants (up to 500wt%), and were successfully tested as carrier materials of hydrocarbon(HC)-degrading bacteria for bioremediation. The bioremediation efficiency of the scaffold-bacteria system was analyzed on crude oil and n-alkanes using two highly performant HC-degrading bacterial strains: the marine hydrocarbonoclastic model strain Alcanivorax borkumensis SK2 and the soil long-chain n-alkane degrader Nocardia sp. SoB.Morphological analysis highlighted a high capacity of adhesion and proliferation of bacterial cells within the whole interconnected three-dimensional structure. HC degradation rates, evaluated by GC-FID analysis, demonstrated the higher degrading performance of immobilized-cells if compared with conventional submerged liquid culture.

Highly Hydrophobic ZIF‐8/Carbon Nitride Foam with Hierarchical Porosity for Oil Capture and Chemical Fixation of CO2

The introduction of hierarchical porosity into metal‐organic frameworks (MOFs) has been of considerable interest in gas separation and heterogeneous catalysis due to the efficient mass transfer kinetics through meso/macropores. Here, a facile, scalable approach is reported for the preparation of carbon nitride (CN) foams as structural templates with micrometer‐sized pores and high nitrogen content of 25.6 wt% by the fast carbonization of low‐cost melamine foam. The nitrogen functionalities of CN foam facilitate chemical anchoring and growth of ZIF‐8 (zeolitic imidazolate frameworks) crystals, which leads to the development of hierarchical porosity. The growth of ZIF‐8 crystals also renders CN foam, which is hydrophilic in nature, highly hydrophobic exhibiting 135° of water contact angle due to the enhanced surface roughness, thus creating a natural shield for the MOF crystals against water. The introduction of ZIF‐8 crystals onto the CN foam enables selective absorption of oils up to 58 wt% from water/oil mixtures and also facilitates the highly efficient conversion of CO2 to chloropropene carbonate in a quantitative yield with excellent product selectivity. Importantly, this present approach could be extended to the vast number of MOF structures, including the ones suffering from water instability, for the preparation of highly functional materials for various applications.

Direct silanization of polyurethane foams for efficient selective absorption of oil from water

Absorption is an effective method to collect oil spills and solvent leakages from water. However, the currently used oil absorbents are still suffering from high cost, tedious preparation, and low recyclability. In this work, we report an extremely simple and low‐cost strategy to produce oil absorbents by directly coupling alkoxysilane onto the surface of polyurethane (PU) foams. Such direct silanization renders the initially amphiphilic foams a strong hydrophobicity and consequently a water‐repelling and oil‐absorptive functionality. The silanized foams exhibit highest absorption capacities as well as best recyclability among all PU‐based oil absorbents. More practically, the silanized PU foams can be used to recover crude oil spills with an absorption capacity of higher than 75 times of their own weight, and maintain 90% of the initial absorption capacity after eight times reusage. Interestingly, we invent portable oil suckers for continuous oil absorption from water by filling vacuum cleaners with the silanized foams. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2232–2240, 2017

One-step modification of PU sponges for selective absorption of oil–water mixtures

Superhydrophobic PDMS–PU sponges fabricated through dipping–coating and HCl corrosion method exhibit excellent oil–water separation property.

Fabrication of recyclable carbonized asphalt‐melamine sponges with high oil‐absorption capability

AbstractBACKGROUNDSelective absorption of oils by macroporous solid absorbents has been regarded as an easy, environment‐friendly and economical way to gather oils for oil–water separation, oil contamination cleanup and easy transport/storage. Cheap absorbent material with high oil‐absorption performance is a key factor to promote its large‐scale application.RESULTSHighly oil‐absorptive and water‐repellent carbonized asphalt‐melamine sponges (AMS) have been prepared via a dip‐coated sponge carbonization process, using deoiled asphalt (DOA) as dip‐coating reagent and melamine sponge (MS) as template. By the combination of DOA‐derived surface modification and mild carbonization at 600°C, the AMS products obtained such key properties as low density, highly selective absorption of oils against water, flexibility, good fire‐resistance and thermal stability, and good recyclability.CONCLUSIONThese findings indicate that AMS can be a promising oil‐absorbent material applicable to oil pollution control on a water surface. Benefiting from both cheap raw materials and facile economical manufacturing process, the approach proposed can contribute to the mass manufacturing of cheap oil‐absorbent products with high oil‐absorption performance. © 2016 Society of Chemical Industry

Robust Superhydrophobic Fabric Bag Filled with Polyurethane Sponges Used for Vacuum‐Assisted Continuous and Ultrafast Absorption and Collection of Oils from Water

Removal of oil from water has become an increasingly important field due to the frequent oil spill accidents as well as industrial oily wastewater. In this study, a bag is made from superhydrophobic fabric and stuffed with pristine polyurethane (PU) sponge just utilizing the synergetic effect of the superhydrophobic and superoleophilic selective absorption of oil from water of the fabric and the excellent large volume‐based oil storage capacity of the PU sponge. The superhydrophobic filling bag can quickly absorb and collect a large amount of oil from a polluted water surface with the separation efficiency always above 98.2% for a series of oil/water mixtures. In addition, the filled orignial sponges exhibit large volume‐based absorption capacity up to 20–36 times its own weight, keeping nearly the same absorption capacity with the previous reported hydrophobic modified sponges. Furthermore, the superhydrophobic bag filled with PU sponges can continuously and efficiently absorb oils from water surfaces with high‐speed, removing about 40 L of kerosene in 150 min under a continuous vacuum regime. Moreover, the as‐prepared superhydrophobic filling bag also shows high selectivity and excellent oil storage stability; and no oil escapes from the bag even under harsh conditions, including strong acidic, alkaline, salt aqueous solutions, hot water, and mechanical abrasion.

Bionic creation of nano-engineered Janus fabric for selective oil/organic solvent absorption

We present a self-driven and tunable hydrophobic/oleophilic, wettability-modified Janus fabric composed of a cellulosic substrate engineered with nanofibersviafacile a electrospinning technique that exhibits one-step selective oil absorption capacity from water.

A superhydrophobic poly(dimethylsiloxane)-TiO2 coated polyurethane sponge for selective absorption of oil from water

The development of promising superhydrophobic absorption materials for the treatment of oil spills and chemical leakage is significant to environmental protection. Herein, a novel superhydrophobic poly(dimethylsiloxane) (PDMS)-TiO2 coated polyurethane (PU) sponge was facilely fabricated by sol–gel growth of TiO2 nanoparticles on the surface of PU sponge, followed by in situ polymerization of PDMS. The as-prepared PDMS-TiO2-PU sponge shows a superhydrophobic surface with a water contact angle of 154° and exhibits high sorption capacities of more than 16.7 g g−1 for the studied oils and organic compounds, such as pump oil, diesel oil, silicone oil, edible oil, kerosene, dichloromethane, and chloroform. Fast sorption speed and high sorption selectivity are achieved for diesel oil sorption. The absorbed oil can be retrieved by simple mechanical extruding the sponge, and the recovered sponge can be used repeatedly over 60 times without obvious decrease in sorption capacity. These results suggest that the prepared PDMS-TiO2-PU sponge may be used in the cleanup of oil spills and the removal of organic pollutants from water.

Optimization Synthesis Conditions and Characterization of Oil Biosorbent: Sugarcane Bagasse Cellulose-Graft-Polystearylmethacrylate Copolymer

In this research, sugarcane bagasse cellulose, an abundant non-wood plant fibrous raw material from Guangxi, was the substrate, stearyl methacrylate was the monomer, and ammonium persulfate was the initiator used to prepare an economical environmental oil biosorbent named sugarcane bagasse cellulose-graft-polystearylmethacrylate (SBC-g-PSMA), which can be obtained through homogeneous graft copolymerization in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). Confirmation of successful synthesis was rendered using various analytical tools, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-Ray Diffraction (XRD). Furthermore, the effects of various reaction parameters on the sorption capacity were all evaluated. Optimum conditions for the synthesis process were obtained as follows: the mass ratio of the monomer to sugarcane bagasse cellulose was 4:1, and the initiator to sugarcane bagasse cellulose ratio was 1:10, with a reaction time of 2 h. Under the optimum conditions, the maximum sorption capacities of the SBC-g-PSMA for 0.2 wt% hydrocarbon (benzene, kerosene, and diesel) were 10.24 g/g, 9.76 g/g, and 9.74 g/g, respectively. The SBC-g-PSMA was light and hydrophobic. It is a selective oil absorption material, so it holds promise to be applied in the treatment of low concentration oily wastewater.

Ultralight carbon aerogel from nanocellulose as a highly selective oil absorption material

The synthesis of a sponge-like carbon aerogel from microfibril cellulose, with high porosity (99 %), ultra-low density (0.01 g/cm3), hydrophobic properties (149° static contact angle) and reusability is reported in this paper. The physical properties, internal morphology, thermal properties, and chemical properties of carbon aerogels heat-treated at 700 and 900 °C (Samples C-700 and C-900) were examined. Stabilization and carbonization parameters were optimized in terms of residual carbon yield. The BET surface area of Sample C-700 (521 m2/g) was significantly higher than of Sample C-950 (145 m2/g). Graphitic-like domains were observed in C-950. The highest normalized sorption capacity (86 g/g) for paraffin oil was observed in sample C-700. The removal of hydrophilic function groups during carbonization causes carbon aerogel to present highly hydrophobic properties. Carbon aerogel’s ability to absorb oil is enhanced by its highly porous 3D network structure with interconnected cellulose nanofibrils.

Durable superhydrophobic/superoleophilic PDMS sponges and their applications in selective oil absorption and in plugging oil leakages

A facile method for preparing porous polydimethylsiloxane (PDMS) sponges is reported. The PDMS sponges are fabricated by the polymerization of the PDMS prepolymer and a curing agent in dimethicone using NaCl microparticles as the hard templates. The porous structure of the PDMS sponges is controllable simply by regulating the weight ratio of prepolymer to dimethicone and the size of the NaCl microparticles. The PDMS sponges feature high compressibility and stretchability, excellent superhydrophobicity/superoleophilicity, as well as high chemical and thermal stability. The PDMS sponge can completely recover its original shape even after 50 cycles of 90% strain. The elongation at breaking the sponge is as high as 97%. The PDMS sponge is superhydrophobic with a water contact angle of 151.5° but can be easily wetted by oils. The sponge also exhibits excellent repellency to corrosive aqueous liquids. The flexibility and superhydrophobicity of the sponge remain unchanged even after keeping in liquid nitrogen or at 250 °C for 24 h. Long-term immersion in various organics has no obvious influence on superhydrophobicity, oil absorbency, or weight of the sponge. The PDMS sponge can selectively absorb a large amount of floating oils on the water surface and heavy oils under the water, and furthermore, is reusable. Moreover, the PDMS sponge swells quickly after the adsorption of oils, which makes it a promising material for plugging oil leakages.

Synthesis of P (St-DVB)/Fe3O4 microspheres and application for oil removal in aqueous environment

In this article, magnetic P (St-DVB)/Fe3O4 microspheres with hollow and porous structure were successfully fabricated by a seed swelling polymerization process for fast and selective absorption of oils from water surface. These microspheres, with unsinkable, magnetic, hydrophobic and oleophilic properties, were used to absorb different oils up to 8.42 times of the particles’ weight while repelling water completely. More importantly, the oil-absorbed microspheres could be removed from water surface efficiently via introducing an external magnetic field. This material also shows excellent reusability after washing with ethanol and the oil-absorption capacity of the material was not sharply reduced even after the 10th cycle. The discoveries presented in this study might provide a low-cost, effective, and environmental-friendly approach for the clean-up of oils and organic solvents on the water.