High Oil Adsorption Capacity Research Articles

Amphiphilic Graphene Aerogel with High Oil and Water Adsorption Capacity and High Contact Area for Interface Reaction

Aerogel is a kind of novel material used to create an amphiphilic surface because of its 3D network structure and functional pore feature. Amphiphilic aerogel can be used as an excellent candidate for the supporter of interface reaction. Hydrophilic domains are highly distributed on the hydrophobic surface, which is beneficial for the two phases to come in contact with each other. In the present work, an amphiphilic graphene-based aerogel (EDGA) is cross-linked by ethylenebis(nitrilodimethylene)tetraphosphonic acid. The EDGA shows high mass adsorption capacity of both oil and water recyclability. The EDGA is used as a supporter of interface reaction. First, we decorate the nanocatalyst on the hydrophilic domain of the EDGA beneficial for its amphiphilicity. Then, this nanocatalyst-loaded EDGA is used as the supporter of the interface polymerization. This kind of a catalyst shows high efficiency for C-H activation. The synthesis strategy can extend the application scope of the multifunctional graphene-based aerogel.

Robust superhydrophobic/superoleophilic sponge for efficient removal of oils from corrosive aqueous solutions

Separation of oil/water mixtures became a significant worldwide issue because of the frequent oil leakage incidents in marine. Herein, a robust superhydrophobic/superoleophilic porous polyurethane (PU) sponge was fabricated just by simple one-step procedure of dip-coating of OTS. The modified PU sponges possessed a superhydrophobicity with water contact angles (CAs) exceeding 156°. The as-prepared sponge exhibited high oil adsorption capacity, robust recyclability for oil/water separation even under strong acid, alkali and salt conditions. Furthermore, when the as-prepared sponge was connected to a vacuum system, the sponge could efficiently remove up to 100 mL kerosene within 25 s under a vacuum of 30 kPa. The simple fabrication process and favorable durability make the sponge a promising candidate for using in a large-scale marine oil leakage clean-up.

Smart carbon foams with switchable wettability for fast oil recovery

The adsorption and recovery of crude-oil from oily water using oil-selective adsorbents is a highly promising solution for the increasing worldwide oil pollution, but remain a challenge. Herein, we reported a carbon foam (CF) with switchable wettability as smart materials for fast oil adsorption and recovery. By grafting poly(4-vinylpyridine) (P4VP) onto the surface of CF, the obtained smart foam presented a pH responsiveness and could change superhydrophilic and superhydrophobic surface according to the pH value. Thus, the smart responsive carbon foam could fast adsorb the oil in neutral solution (pH = 7) with high oil adsorption capacity of 62–120 g g−1 and desorb all the adsorbed oil in acidic solution (pH = 1) within 1.5 min. In addition, only 3% loss was observed for oil (chloroform) adsorption and recovery after successive reuses of up to 15 cycles, which demonstrated great recyclability of the materials.

Polyurethane Synthetic Papers Based on Different Inorganic Fillers with Water and Fire Resistance

AbstractPolyurethane synthetic papers based on different inorganic fillers are prepared via wet phase inversion process and inorganic mineral filling modification technique. The surface and cross‐section morphology, tensile strength and elongation at break, fire resistance, water and oil adsorption, ink contact angle, writing and printing effects, and water resistance of synthetic paper are investigated, respectively. A large number of pores are present on the surface and in the interior of the synthetic papers and provide huge space for ink molecules. The synthetic paper with transparent powder filled exhibits the optimal performance in tensile strength and elongation at break. Moreover, the fire resistance of polyurethane is improved by inorganic particles, and the highest limit oxygen index value of synthetic paper reaches up to 31.8%, which meets the standard of flame retardant. Meanwhile, filled synthetic papers exhibit high water and oil adsorption capacity, good ink‐affinity, excellent writing and printing effects. In addition, filled synthetic papers perform well in water resistance when written and printed synthetic papers are immersed in water. This work may provide a new idea to design a novel, greener, and multifunctional synthetic paper for its broad applications.

Preparation of oil sorbents of corn straw and its application in oil-water separation

The leakage of crude oil at sea and the discharge of domestic oily wastewater are likely to cause environmental pollution and threaten human health. Therefore, the development of techniques for the collection and recovery of the large amount of oil from water is attracting worldwide attention. To deal with the polluted water by spilled oil, materials with special wettability have been designed and developed over the past decades. Currently, metal meshes, sponges and cotton fabrics as well as particles with superhydrophobicity/superoleophiliciy or superhydrophiliciy/superoleophobicity have often been employed to separate oil and water mixtures. However, how to remove the spilled oil from water via techniques of low operation cost, high separation selectivity and efficiency as well as good recoverability for reuse without causing secondary contamination to environment is still a big challenge. Consequently, it is highly desirable to develop a new and advanced oil-water mixtures separation material that can selectively absorb oil while completely repelling water. Cellulose is the most abundant organic polymer, which is mainly used as a raw material to produce paper and cotton fabrics. Plant-derived cellulose is an important structural component of the primary cell wall of green plants, and usually found in a mixture with hemicellulose, lignin, pectin and other substances. Corn is a very common crop and widely planted in the Zhangye district of Gansu Province in China, and the corn straw are very abundant after harvest in autumn. However, the unused and accumulated corn straw can be easily rotted and hence cause the waste of resources, and the traditional treatment of burning can also induce serious environment pollution. With the consideration of the wide source, low cost, light weight, high oil adsorption capacity, good floatability in water as well as easy recycling, the corn straw is an ideal raw material which can be employed to prepare oil sorbent. In this research, corn straw was employed to fabricate oil sorbent. Corn straw was first crushed and then immersed into ZnO sol for 24 h, subsequently, corn straw powders were taken out and dried in air at 80°C. Finally, the dip-coated corn straw powders were immersed in octyltrimethoxy silane (OTS) solution for 24 h, taken out and dried at 120°C, and then, the corn straw powders begun to exhibit superhydrophobicity and superoleophilicity. Water contact angle on the superhydrophobic corn straw powders is 158.6° and the sliding angle of water droplet is about 4°, but the oil droplets can spread out completely on the corn straw powders due to the superoleophilicity. Synergy effects between surface morphology and surface chemical composition are known as the crucial factors to realize the opposite wettability to oil and water. The surface morphology and surface chemical composition of the obtained corn straw powders with superhydrophobicity and superoleophilicity were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectrum (XPS), respectively, and the wettability were measured with an optical contact angle meter at ambient temperature. The research indicates that both the dip-coating ZnO sol and surface modification with OTS play an important role for the performance of superhydrophobicity and superoleophilicity of corn straw powders. Because water and many oils are intrinsically immiscible, and the corn straw powders with extremely different affinities towards oils and water can be employed to separate oil-water mixtures by ways of filtration, and the separation efficiency towards water and oil is up to 99.6% and 98.0%. In addition, the spilled oil on water can also be removed by adsorption. Compared with the adsorption capacity of the pristine corn straw powder to spilled oil, the adsorption capacity of superhydrophobic corn straw powder is much high, and the corresponding adsorption capacity is 2.1 and 3.8 g/g, respectively. Moreover, the corn straw and spilled oil adsorbed by superhydrophobic corn straw can be reused and recovered by treatment of high speed centrifugation. When the adsorption time increased from 1 to 10, the water contact angle on the recovered corn straw powders is still about 156°±1°, and the corresponding sliding angle of water is about 8°, and the average percentage of recovery of superhydrophobic corn straw to hexadecane is above 70%. The design and fabrication of oil sorbent of superhydrophobic-superoleophilic corn straw made by dip-coating ZnO sol and modifying with OTS are expected to provide a new idea for the processing and utilization of corn straw as well as preparation of oil sorbents.

Facile and scalable fabrication of superhydrophobic and superoleophilic PDMS-co-PMHS coating on porous substrates for highly effective oil/water separation

Superhydrophobic/superoleophilic (SHBOI) porous materials have attracted significant interest in the field of oil/water separation, however, fabricating SHBOI porous materials though a low cost, one-step and simple strategy is still a great challenge. In this work, a facile approach is developed for scaling the production of SHBOI porous materials by the deposition of SHBIO PDMS-co-PMHS coating onto porous materials via a facile surface coating method without the use of nanoparticles and fluorinated compounds. Meanwhile, the PDMS-co-PMHS coating is constructed by hydrosilylation reaction between vinyl bonds of vinyl-terminated-poly(dimethylsiloxane) (VPDMS) and silicon-hydrogen bond of trimethylsilyl-terminated-poly-(dimethylsiloxane)-co-polymethylhydrosiloxane (TPDMS-co-PMHS), and simultaneously attached on various porous substrates including sponge (SP), fiber paper (FP), glass fiber (GF) membrane, etc. As a result, PDMS-co-PMHS coating provides SHBOI and excellent oil/water separation characteristics to the porous substrates. According to the results, PDMS-co-PMHS@SP possesses SHBOI characteristics, high oil-adsorption capacity (up to 143 times its original weight) and excellent recyclability. PDMS-co-PMHS@FP can efficiently separate a series of immiscible oil/water mixtures in a single-step based on its high oil or organic solvents fluxes (about 2000–3000 L.m−2.h−1) and SHBOI characteristics. In addition, PDMS-co-PMHS@GF membrane exhibits great water rejection (∼99.90%) for separating water-in-oil emulsions under gravity-driven condition. Thus, a new strategy employing PDMS-co-PMHS as a coating material to modify porous substrates has great potential for developing a scalable method of fabricating SHBOI porous materials for oil/water separation.

Flexible membranes with a hierarchical nanofiber/microsphere structure for oil adsorption and oil/water separation

Oil spill and oily wastewater have now become a serious threat to the freshwater and marine environments. Porous materials with super-hydrophobicity and super-oleophilicity are good candidates for the oil adsorption and oil/water separation. Here, flexible hybrid nanofibrous membrane (FHNM) containing SiO2/polyvinylidene fluoride (PVDF) microspheres was prepared by simultaneous electrospinning and electrospraying. The obtained FHNM combined the flexibility of the nanofiber mat and super-hydrophobicity of the microspheres, which could not be achieved by either only electrospinning or only electrospraying. It was found that when the weight ratio between the SiO2 and PVDF reached a critical value, the SiO2 nanoparticles were present on the PVDF microsphere surface, significantly improving the surface roughness and hence the contact angle of the FHNM. Compared with the pure electrospun PVDF nanofiber mat, most of the FHNMs have a higher oil adsorption capacity. The FHNM could separate the oil with water quickly under the gravity and displayed a high efficiency and good reusability for the oil/water separation. More importantly, the FHNM could not only separate the oil with the pure water but also the corrosive solution including the salt, acid and alkali solution.

A novel hydrophobic adsorbent of electrospun SiO2@MUF/PAN nanofibrous membrane and its adsorption behaviour for oil and organic solvents

With increasing oil spill accidents, the development of effective and low-cost adsorbents with good hydrophobicity is highly desirable. To cope with the clean-up of oil spill, a hydrophobic adsorbent was synthesized by electrospinning using inexpensive raw materials. By ingeniously combining melamine with polyacrylonitrile (PAN) as well as SiO2 nanoparticles, a novel composite nanoadsorbent named SiO2@MUF/PAN nanofibrous membrane was prepared and characterized. The adsorbents were conducted based on uniform nanofibre networks and were abundant with narrow slit-like pores, which are significant for the retention of oil and organic solvents. The hydrophobicity of the as-prepared membranes was enhanced with an increasing amount of SiO2, and the highest water contact angle was 128.3°. Furthermore, the combination of SiO2 and melamine increased the thermal stability of the membranes. With the unique pore structures and hydrophobicity, the membranes were able to selectively remove not only oil but also organic solvents from water surface. The adsorption capacities of the membranes with SiO2 nanoparticles (0.9 wt%) were the highest and that for peanut oil, diesel, pump oil and engine oil were 19.09, 13.12, 18.48 and 22.67 g g−1, respectively, while that for organic solvents ranged from 12.92 to 22.16 g g−1. After 10 adsorption–regeneration cycles, the adsorption capacity was still around 35% of the initial value. Due to its high oil adsorption capacity, excellent reusability and the cost-effective hydrophobic, SiO2@MUF/PAN have a great potential for oil spill clean-up.

Responses of laying hens to the simultaneous dietary supplementation with flaxseed and dried tomato by-products

Apple (AP), blueberry (BP), red raspberry (RP), and cranberry pomace (CP), were evaluated for their physicochemical and functional properties and bioactive compounds (i.e. dietary fibers and phenolics) as potential functional food ingredients. Bound phenolics in AP, BP, and CP could be liberated through simulated gastrointestinal digestion (SGD). Among all tested fruit pomace (FP), RP contained the highest total phenolic content based on both chemical extraction and SGD. AP contained the highest soluble dietary fiber obtained from AOAC method and SGD, while it presented the lowest insoluble dietary fiber in comparison with BP, RP, and CP. Total dietary fiber content of RP and CP from SGD was significantly (P < 0.05) higher than that from AOAC method. AP exhibited a high water-holding capacity (9.27 g water/g dry weight (DW)) and swelling ability (6.51 mL/g DW), while BP and CP showed high oil-adsorption capacity (1.96 g oil/g DW and 1.97 g oil/g DW, respectively). The differences in the functional properties of the tested FP could be due to their distinguished fiber compositions and structures. This study demonstrated the potential of using FP as fiber-rich and antioxidant functional ingredient that can be selectively utilized in various food applications.

Synthesis of MIL-101@nanoporous graphene composites as hydrophobic adsorbents for oil removal

Abstract The marine environment is being more and more polluted by oil spills on a daily basis, posing a serious threat to humans. The substances possessing high adsorption capacity and hydrophobic nature, generally play an important role in crude oil adsorption from aqueous solutions. The synthesis of new porous materials has attracted attention of many researchers in a large number of systems. Metal Organic Frameworks such as MIL-101(Cr) with high surface area and pore volume have been widely investigated to use in many applications such as separation. To enhance the MIL-101′s properties, hybrid composites with high specific surface area and pore volume have been considered. MIL-101 and MIL-101@ nanoporous graphene (NPG), which have been fabricated for the first time, with different nanoporous graphene contents (30, 60, and 90 wt%) were herein synthesized via a solvothermal method .The prepared adsorbents were characterized using field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectroscopy, thermal gravimetric analysis (TGA), adsorption of nitrogen at 77.4 K, and contact angle (CA). The high oil adsorption capacity (14 g/g) was achieved for the synthesized adsorbents with the high surface area of MIL-101 (4293 m2/g) and MIL-101@NPG 60 wt% (4642 m2/g), and the high pore volume of MIL-101 (2.42 cm3/g) and MIL-101@NPG 60 wt% (2.62 cm3/g). The results show that the crude oil adsorption capacity enhanced by adding NPG to the virgin MIL-101, which is higher than that of previous scientific reports. The conformity of various adsorption models, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D-R) to the equilibrium data were evaluated, and among which Freundlich isotherm model gave the best fitting result. The synthesized adsorbents can be further reused for several times, with no significant adsorption loss capacity and hydrophobicity.

Increasing precipitation rate from sodium aluminate solution by adding active seed and ammonia

Remarkably increasing precipitation rate of sodium aluminate solution was studied by adding active seed and ammonia. The fine active gibbsite seed with irregular edge, large specific area and high oil adsorption capacity was prepared by sodium bicarbonate solution and sodium aluminate. The seeded precipitation rate reached up to 65% by adding <20 g L−1 active seeds into the sodium aluminate solution. Moreover, 75% precipitation rate was obtained due to the coupling contribution from the active seed and ammonia. Ammonia added in the initial precipitation stage improved precipitation rate, whereas minimal change in precipitation rate occurred by adding ammonia in latter period of precipitation. High precipitation rate also led to precipitation of fine gibbsite. In addition, increasing ammonia amount benefitted the formation of Al(OH)4− and slightly reduced the amount of Al2O(OH)62−. Electrical conductivity in solution was decreased by adding ammonia. This is quite probably attributed to the increase in ionic pairs of Na+Al(OH)4− and subsequently precipitation of gibbsite from Al(OH)4−.

Facile preparation of polymer microspheres and fibers with a hollow core and porous shell for oil adsorption and oil/water separation

Non-solvent assisted electrospinning was proposed for fabricating Polymethylmethacrylate (PMMA) microspheres and fibers with a hollow core and porous shell, which could be used for oil adsorption and oil/water separation. Propanediol was chosen as the non-solvent because of its high surface tension and viscosity as well as large phase separation tendency with polymer, which was beneficial to the formation of both the hollow core and porous shell during the electrospinning. With the increase of the polymer solution concentration, the microsphere gradually evolved to the bead-on-string geometry and finally to a continuous fiber form, indicating the transition from electro-spraying to electrospinning. The hollow core and dense surface pores enhanced the hydrophobicity, oleophilicity, permeability, and specific surface area of the fibers, and hence imparted the fibrous mat a high oil adsorption capacity. When the porous hollow microspheres were electro-sprayed onto the stainless steel mesh followed by the PDMS modification, the modified mesh became super-hydrophobic and super-oleophilic with the contact angle of 153° and sliding angle of 4°. The as-prepared mesh showed rapid oil/water separation with high efficiency and excellent recycling performance. The flux for separation of oil/water mixture could reach as high as 11,000 L m−2 h−1. This facile non-solvent assisted electrospinning method provides a new avenue for preparation of multifunctional porous materials which possess potential applications in large-scale oil/water separation.

The efficient lignocellulose-based sorbent for oil spill treatment from polyurethane and agricultural residue of Vietnam

ABSTRACTIn this study, new and efficient sorbent with density 0.2 g/cm3 was fabricated by incorporating rice straw into polyurethane matrix to get an open cell structure material with high oil uptake capacity. The influences of various important factors such as amount of adding rice straw, size of rice straw particles, and adsorption time on oil adsorption capacity of new sorbent material were investigated. The results showed that the oil absorption rate occurred fast in first 15–30 min, then slowed down and reached saturation level after about 2 h of treatment. Oil adsorption capacity of the new sorbent material was relatively high, up to 12.0 g/g. In comparison with pristine polyurethane or lignocellulosic materials, the new sorbents had higher oil adsorption capacity. Some characteristics of the as-obtained sorbent, such as surface shapes and porosity, were also studied by SEM analysis.

A novel hierarchical hollow SiO2@MnO2 cubes reinforced elastic polyurethane foam for the highly efficient removal of oil from water

Oil-polluted water has become a worldwide problem due to ever-increasing industrial oily wastewater as well as the frequent oil spill accident. A superior oil adsorbing material capable of separating oil–water mixtures efficiently, especially with a high oil adsorption capacity and mechanical strength, is urgently desired. Here, we report a novel strategy of preparing composite foams with hierarchical porous structures for effective oil/water separation and selective oil adsorption. The composite polyurethane foam is synthetized by a facile one-step foaming technology, which uses hierarchical hollow SiO2@MnO2 cubes to modify the inner structures of composite polyurethane foam. The incorporation of hierarchical hollow SiO2@MnO2 cubes into the foam could not only improve the morphologies, specific surface areas and hydrophobic properties but also enhance the adsorption capacity and mechanical properties. The as-prepared composite PU foam is put into the oil/water mixture to adsorb oils, and the adsorbed oils can be recovered simply by squeezing oil from composite PU foam. The resulting composite PU foam exhibits high oil adsorption capacity, high selectivity and oil adsorption capacity for carbon tetrachloride was measured to be 31.6g/g. Also, the composite PU foam shows excellent elasticity and the height of the composite PU foam decreased from 100% to 94% after 30 compressing–releasing cycles. Furthermore, the as-prepared composite PU foam exhibits the high reusability and durability by being reused for oil–water separation for 10 cycles without losing its hydrophobicity, which makes it a good candidate for industrial oil-polluted water treatments and oil spill cleanup.

Functional properties, bioactive compounds, and in vitro gastrointestinal digestion study of dried fruit pomace powders as functional food ingredients

Apple (AP), blueberry (BP), red raspberry (RP), and cranberry pomace (CP), were evaluated for their physicochemical and functional properties and bioactive compounds (i.e. dietary fibers and phenolics) as potential functional food ingredients. Bound phenolics in AP, BP, and CP could be liberated through simulated gastrointestinal digestion (SGD). Among all tested fruit pomace (FP), RP contained the highest total phenolic content based on both chemical extraction and SGD. AP contained the highest soluble dietary fiber obtained from AOAC method and SGD, while it presented the lowest insoluble dietary fiber in comparison with BP, RP, and CP. Total dietary fiber content of RP and CP from SGD was significantly (P < 0.05) higher than that from AOAC method. AP exhibited a high water-holding capacity (9.27 g water/g dry weight (DW)) and swelling ability (6.51 mL/g DW), while BP and CP showed high oil-adsorption capacity (1.96 g oil/g DW and 1.97 g oil/g DW, respectively). The differences in the functional properties of the tested FP could be due to their distinguished fiber compositions and structures. This study demonstrated the potential of using FP as fiber-rich and antioxidant functional ingredient that can be selectively utilized in various food applications.

Ultrasonic-microwave assisted synthesis of stable reduced graphene oxide modified melamine foam with superhydrophobicity and high oil adsorption capacities

We herein report the fabrication of recyclable, stable and cost-effective superhydrophobic reduced graphene oxide modified melamine foam (RGMF) through ultrasonic-microwave synergistic method for the first time. In the synthesis process, ultrasonic and microwave irradiation not only shortened the reduction time of graphene oxide (GO) with the existence of reducing agent, but also considerably enhanced the firmness of reduced graphene oxide (rGO) anchored onto the melamine foam (MF). The structure and property of the obtained RGMF were characterized by XRD, Raman, SEM and contact angle measurements. The results showed that the skeletons of MF were completely covered with rGO layers which were compact and full of wrinkles. The as-prepared RGMF was superhydrophobic without further modification. Besides, the RGMF showed excellent selective adsorption capacity of various oils and organic solvents from water. The maximum oil adsorption capacity was 112 times of the weight of the initial MF, and the adsorption capacity of the RGMF did not deteriorate after it was reused 20 times. More importantly, the RGMF showed good stability against cavitation erosion and corrosion liquids. All these features made the as-prepared material an ideal candidate for removal and collection of oils and organic solvents from water.

Corn cob modified by lauric acid and ethanediol for emulsified oil adsorption

Corn cob is a naturally renewable material with developed micropore and hydrophobic characteristics, which enables it to show good oil adsorption capacity. In order to improve oil adsorption capacity, corn cob was modified with lauric acid and ethanediol. The structure of raw and modified corn cob was investigated using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA) and ZeTa potential analyzer. The effects of pH level, adsorption time, adsorbent dosage, and initial oil concentration on oil absorbency of corn cob were studied. The results indicate that the modification significantly improved the lipophilicity of corn cob, making the modified corn cob with much better adsorption capacity on oil absorbency. Compared with raw corn cob, the maximum saturated adsorption capacity of modified corn cob is 16.52 mg/g at pH 5, and the increasing percentage is found to be 141%, which indicates that the modification causes a better adsorption capacity for oil removal. In addition, due to high oil adsorption capacity, affordable price and low secondary pollution, the modified corn cob could be considered promising alternative for the traditional oil adsorbent to clean up the emulsified oily water.

Enhanced Removal of Oil Droplets from Oil-in-Water Emulsions Using Polyethylenimine-Modified Rice Husk

Although several nano-materials have been used to adsorb oil droplets in water, preparing these materials requires complex procedures and expensive reagents. Their implication to the environment also remains unclear. Thus, in this study, we propose to develop efficient, inexpensive and environmental-friendly oil-removing adsorbents. To this end, we select an agricultural waste, rice husk (RH), as an adsorbent. To enhance the oil-removing performance, RH are modified with a biocompatible cationic polymer, polyethylenimine (PEI). The as-prepared PEI–RH was characterized using SEM, FT-IR, and TGA, and used to adsorb oil droplets in water. PEI–RH was found to exhibit a much higher oil adsorption capacity than RH. The oil adsorption kinetics and isotherm were measured and analyzed using theoretical models. The thermodynamic parameters of the oil adsorption were also determined. The factors affecting the oil adsorption to PEI–RH were examined including temperature, size of PEI–RH, pH, salt and surfactants. The higher temperature was found to enhance the oil adsorption capacity, whereas smaller size of PEI–RH exhibited a much higher adsorption capacity. The adsorption capacity of PEI–RH remained quite stable in the pH range of 5–7, while the highly acidic and basic conditions were not preferable for PEI–RH to separate oil-in-water emulsions. The addition of NaCl slightly improved the oil adsorption capacity but the presence of surfactants decreased the oil adsorption capacity of PEI–RH. PEI–RH also could be reused for multiple cycles after a simple ethanol washing method. These features enable PEI–RH a promising and low-cost adsorbent for the separation of oil-in-water emulsions.

Fabrication and oil adsorption of carbon nanotube/polyvinylpyrrolidone surface composite.

It needs to assemble the industrial CNT powders into macroscopic porous surface composite to utilize the surface properties of CNTs, as well as to prevent them entering into environments. We demonstrate a method to fabricate the surface composites from CNTs and polyvinylpyrrolidone (PVP) by electrospinning, where CNTs distribute firmly and mainly on the surface PVP nanofibers. The CNTs/PVP surface composites have high pore volume of 10 cc/g and remarkable CNTs load of 98%. Thus the surface composites show high oil adsorption capacity of 0.9~1.1 g/cm3. It can absorb more oil than commercial sponges due to the surface composite swells after absorbing oil. It shows attractive potential application of the CNT/PVP surface composite in oil spill cleanup.

Preparation of regenerated keratin sponge from waste feathers by a simple method and its potential use for oil adsorption

In this work, pigeon feathers, a kind of totally waste by-product from the poultry industry, were utilized to fabricate a highly porous keratin sponge in a very simple way by freeze-drying treatment of the dissolved keratin solution, and applied for the first time as an oil adsorbent. An improved method was proposed to dissolve the feather keratin using the inexpensive sodium disulfite as the reducing reagent for sulfitolysis reaction, with a much lower concentration of all involving reaction regents. Moreover, the regenerated keratin sponges obtained a high oil adsorption capacity of above 30g/g for both liquid paraffin and soybean oil, as well as a good oil holding ability, suggesting that this keratin sponge might be a potential for use as oil adsorbent.