聚二甲基硅氧烷/微纳米银/聚多巴胺修饰的超疏水海绵的制备和应用

受海洋贝类生物黏附蛋白的启发,在碱性环境下利用多巴胺的自聚合性质,在聚氨酯海绵表面聚合活性聚多巴胺薄层,采用葡萄糖还原银离子进一步沉积微纳米银粒子构筑表面微纳结构,并水解聚二甲基硅氧烷前驱体对表面进行疏水改性,制备出了接触角大于150°的超疏水表面。利用接触角测定、扫描电子显微镜及能量弥散X射线谱和傅里叶红外光谱等技术手段对制备的改性海绵进行了表征,表明微纳米银粒子和硅甲基疏水基团被成功修饰到了海绵表面。改性海绵对有机溶剂和油类物质具有高选择性和高吸收性。吸收的有机溶剂和油类物质的质量能够达到其自身质量的12倍以上。饱和吸收后的海绵仅通过物理挤压即可将吸收的物质回收并使海绵恢复弹性和吸附能力,得到再生。该研究为油水分离和废油回收提供了一种经济、高效、环境友好的方案。     

Application of Nano-Hydroxyapatite Derived from Oyster Shell in Fabricating Superhydrophobic Sponge for Efficient Oil/Water Separation

The exploration of nonhazardous nanoparticles to fabricate a template-driven superhydrophobic surface is of great ecological importance for oil/water separation in practice. In this work, nano-hydroxyapatite (nano-HAp) with good biocompatibility was easily developed from discarded oyster shells and well incorporated with polydimethylsiloxane (PDMS) to create a superhydrophobic surface on a polyurethane (PU) sponge using a facile solution–immersion method. The obtained nano-HAp coated PU (nano-HAp/PU) sponge exhibited both excellent oil/water selectivity with water contact angles of over 150° and higher absorption capacity for various organic solvents and oils than the original PU sponge, which can be assigned to the nano-HAp coating surface with rough microstructures. Moreover, the superhydrophobic nano-HAp/PU sponge was found to be mechanically stable with no obvious decrease of oil recovery capacity from water in 10 cycles. This work presented that the oyster shell could be a promising alternative to superhydrophobic coatings, which was not only beneficial to oil-containing wastewater treatment, but also favorable for sustainable aquaculture.     

树莓状超疏水多孔复合棉纤维的制备及油水分离性能

基于聚多巴胺（PDA）的化学性质和树莓状纳米粒子的粗糙结构,以聚多巴胺包覆的棉纤维为基底,制备了具有多重粗糙度的树莓状超疏水多孔复合棉纤维材料.通过扫描电子显微镜观察树莓状超疏水多孔复合棉纤维表面的微观形貌,PDA-SiO₂纳米粒子稳定地固定在聚多巴胺涂覆的棉纤维表面.经过氟化改性的树莓状超疏水多孔复合棉纤维具有超疏水性,水接触角为158.2°,油接触角为0°.油/水分离实验结果表明,树莓状超疏水多孔复合棉纤维对己烷/水混合物的分离效率可达99.4%以上,使用20次后仍维持较高的分离效率.同时,其具有较高的溶剂吸附能力（13~34 g/g）、重复使用性及机械稳定性,吸油能力可与硅气凝胶相媲美.     

Continuous separation of oil from water surface by a novel tubular unit based on graphene coated polyurethane sponge

We develop a new strategy for the continuous separation of oil from water surface using a novel tubular unit based on graphene coated polyurethane (P‐GEPU) sponge, and the P‐GEPU sponge was fabricated by a simple dip‐coating method; the as‐prepared sponges could adsorb different kinds of oil and organic liquids while repelling water. Moreover, the tubular unit was assembled by wrapping the P‐GEPU sponge on a porous PU hollow tube and combined with the accessories including pipes and joints. The tubular unit could float on the surface of water, and a continuous oil collection from water surface through vacuum pressure could be fulfilled, showing a high oil‐water separation efficiency (>96%). Finally, oil‐water separation efficiency remains above 93% after 10 cycles, exhibiting excellent reusability. In addition, our findings are easily scaled up, showing a great promise for large‐scale oil spill remediation.     

Preparation and morphology control of three‐dimensional interconnected microporous PDMS for oil sorption

This study described an approach to impart controlled morphology and improved pore interconnectivity to poly(dimethylsiloxane) (PDMS) sponges for oil sorption by partially fusing the sugar particles together prior to creation of a continuous PDMS matrix. PDMS sponges with high absorption capacity, low water pickup, and remarkable reusability were fabricated by the polymerization of the PDMS prepolymer and a curing agent in cyclohexane. The PDMS sponge showed oil absorbency in the range from 790% to 4000% for various oils solvents, with the maximum absorption capacity reaching up to 23 times of its weight. Compressive modulus of PDMS subjected to sugar fusion for 24 hr was significantly increased to 1900 Mpa. The sponge also exhibited excellent repellency to corrosive strong acid and alkali. Besides, oil can be quickly adsorbed in tens of seconds and maintained for several months. Furthermore, PDMS sponges showed little loss of their absorption capacities and owned weights after 20 absorbing/recovering cycles. Copyright © 2015 John Wiley & Sons, Ltd.     

Peristome‐Mimetic Curved Surface for Spontaneous and Directional Separation of Micro Water‐in‐Oil Drops

Separation of micro‐scaled water‐in‐oil droplets is important in environmental protection, bioassays, and saving functional inks. So far, bulk oil–water separation has been achieved by membrane separation and sponge absorption, but micro‐drop separation still remains a challenge. Herein we report that instead of the “plug‐and‐go” separation model, tiny water‐in‐oil droplets can be separated into pure water and oil droplets through “go‐in‐opposite ways” on curved peristome‐mimetic surfaces, in milliseconds, without energy input. More importantly, this overflow controlled method can be applied to handle oil‐in‐oil droplets with surface tension differences as low as 14.7 mN m⁻¹ and viscous liquids with viscosities as high as hundreds centipoises, which markedly increases the range of applicable liquids for micro‐scaled separation. Furthermore, the curved peristome‐mimetic surface guides the separated drops in different directions with high efficiency.     

Cleanup of Water Surface from Oil Spills Using Natural Sorbent Materials

The following indicators were used to compare sorption efficiency of the test objects: oil capacity (OC), buoyancy, solubility of hydrocarbons in water, and water absorption (WA). Hereby, it was determined that the peat moss carbonized at the temperature of 200-250°С and modified by acetic acid has high sorption capacity. The sorbents introduced can increase the efficiency of water surface cleaning up until the water is almost clean and the residual oil content in water is less than 0.03 g/l.     

羊毛表面改性对拒水拒油整理的作用及机理研究

应用扫描电镜(SEM)、X射线光电子能谱(XPS)和衰减全反射红外光谱(FTIR-ATR)等现代表面分析技术研究不同改性处理羊毛表面的化学和物理结构特性.SEM研究结果表明,经低温等离子体表面改性或特定化学改性后的羊毛鳞片表面呈现纳米尺度的沟槽和凹凸结构,应用Wenzel公式和Cassie and Baxter公式阐述了表面粗糙度与接触角的关系,揭示了羊毛表面改性对于提高拒水拒油整理效果的原因所在.XPS和FTIR-ATR研究表明,上述物理和化学的表面改性技术使羊毛表面的二硫键氧化断裂和表面类脂物质改性/除去,促进拒水拒油整理剂的吸附和固着.表面改性和拒水拒油整理的协同效应赋予羊毛类荷叶效应,使其呈现超级拒水拒油拒污功能.     

Preparation and properties of polyvinyl acetal sponge modified by chitosan

The polyvinyl acetal sponge modified by chitosan was prepared by adding chitosan/polyvinyl alcohol (PVA) solution during the acetalation reaction of PVA and formaldehyde. The effect of vesicant and chitosan to the pore morphology, water absorption ratio, water absorption rate, expansion time and mechanical properties were studied. The polyvinyl acetal sponge modified by chitosan was used as a hemostatic packing material for the injured rabbit nasal tissue. The hemostatic effect and the healing effect of the modified sponge on the nasal mucosa after nasal surgery were studied. The results indicated that the polyvinyl acetal sponge modified by chitosan has an interconnected pore structure and the wall between large pores also has small pores. The chitosan adhered on the inner surface of the pores. The increased content of vesicant led to an increase in pore diameter, in the water absorption ratio and in expansion time. However, there was only a small change in the water absorption rate and a decrease in tensile strength and compression strength were noted. With an increase in chitosan content, the pore diameter and interconnection of the sponge was reduced. Water absorption ratio, expansion time and water absorption rate decreased, but tensile strength and compression strength improved. Observation of the rabbit nasal tissue after surgical operation suggested that polyvinyl acetal sponge modified by chitosan has an anti-inflammatory, hemostatic and anti-adherent characteristic and could promote the healing and functional recovery of rabbit nasal mucosa. __________ Translated from Journal of Jinan University (Natural Science & Medicine Edition), 2007, 28(3): 283–287 [译自: 暨南大学学报(自然科学与医学版)]     

Properties of Langmuir Surface and Interfacial Films Built up by Asphaltenes and Resins: Influence of Chemical Demulsifiers

The influence of chemical additives on asphaltene films on water surface and at oil/water interface is studied by means of the Langmuir technique. It was found that some demulsifiers of high molecular weight alter the asphaltene film on water surface in the same way as the resin fraction, i.e., increasing the compressibility of the film which results in a reduced film rigidity. The films that build up at the oil/water interface in model oil systems, containing naturally occurring surfactants, are studied during compression. In this system chemical additives of high molecular weight totally prevent formation of a rigid film at the interface. Adding resins to the bulk phase together with asphaltenes hamper the adsorption of the heavy fraction.     

Facile fabrication of asphaltene-derived graphene-polyurethane sponges for efficient and selective oil-water separation

Based on the natural graphene-structure in the raw asphaltene material, a graphene-polyurethane sponge (GPU) oil-absorption material was prepared via a facile and inexpensive route of dip-coated sponge carbonization, which used low-value petroleum asphlatene as the dip-coating reagent and polyurethane sponges as the template. The GPU presents high hydrophobic and super oleophilic properties, as well as the excellent oil absorption performance. And its chloroform absorption capacity could reach 123 times its original mass, which is significantly higher than that of most reported oil absorbents. Furthermore, the GPU exhibits good recyclability. It has the promising applications in the pollution control of spilt oil.     

Super-hydrophobic carrageenan cross-linked graphene sponge for recovery of oil and organic solvent from their water mixtures

A novel ultra-light, superhydrophobic graphene based carrageenan sponge (GCS) absorbent was synthesized by one pot hydrothermal method, for the use of selective adsorption of oils and organic solvents from their water mixtures. The GO nanosheets were reacted in the presence of formaldehyde by the insertion of carrageenan, forming hydrophobic cross-linked structure in between them. The structure and properties of this GCS are well characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Thermal gravimetric analysis, Scanning electron microscopy, and Water contact angle. The as-prepared GCS has good thermal stability (400 °C), low density (20 mg/cm⁻³), excellent hydrophobicity (water contact angle of 136.24°), and selective absorption capacity (25.2–35.95 g/g) of oils and organic solvents from their water mixtures. GCS has excellent oil sorption capacity in the range of 25.2–50 g of oil per gram of adsorbent. GCS could be easily reused by simple solvent treatment. Therefore, the adsorption capacity still retained even after 10 cycles. The present work suggests that GCS using biobased resources has high potentials for many widespread applications in industry to control environmental pollution.     

3D hierarchical MnO2 aerogels with superhydrophobicity for selective oil–water separation

Inorganic nanowire aerogel with low density, high specific surface area and high porosity has received increasing attention in the field of materials physics and chemistry because of not only the unique structural and physical features of metallic oxide but also low cost, environmental friendliness and earth abundant of precursor materials. In this work, MnO₂ nanowire aerogels (MNA) with ultralow density, and stable 3D hierarchical structures was successfully fabricated by freeze‐drying processes using MnO₂ nanowire as building blocks. The length of MnO₂ nanowires exceeds 100 μm, making it easier to cross‐link and self‐assemble into a 3D network of aerogels, and the acid and alkali resistance of MnO₂ enables it to adapt to extreme environments. Simultaneously, the monodispersed MnO₂ nanowire was prepared by the hydrothermal method, followed by acid treatment. To obtain superhydrophobic properties and achieve selective oil adsorption, the surfaces of nanowire aerogels were grafted the hydrophobic groups with low surface energy via vapor deposition. It is indicated that the obtained 3D hierarchical MNA show both superhydrophobic and super‐lipophilic properties simultaneously with a high‐water contact angle of 156°  ±  2° and an oil contact angle of 0°. And the MNA exhibited a high oil adsorption capacity of 85–140 g/g, thereby indicating its potential applications in oil/water separation. More importantly, the resulting MNA can be recycled ten cycles without loss of oil absorption capacity (more than 120 g/g). The results presented in this work demonstrate that the as‐prepared nanowire aerogel may find applications in chemical separation and environmental remediation for large‐scale absorption of oils from water.     

Emulsification through surfactant hydration: the PIC process revisited

We have performed sudden composition changes on a (surfactant + oil + water) system by adding water to a (surfactant + oil) solution. This composition change quenches the system into a metastable oil-in-water emulsion with a population in the 100 nm range. The conditions for a successful quench are as follows: the initial water content should be below a boundary called the "clearing boundary" (CB), the final water content should be sufficiently beyond CB, and the quench should be fast. We have used high purity components to avoid the complex phase separation patterns that occur with low purity ingredients: the surfactant is octaethylenehexadecyl ether (C(16)E(8)) and the oil is hexadecane (C(16)). Under these conditions, we show that the pathway for this type of quench proceeds through the swelling of the reverse micellar phase by the added water and the formation of a sponge phase. Then, further water addition causes the nucleation of oil droplets in this sponge phase, with a size that matches the spontaneous curvature of the sponge phase. Part of the surfactant remains adsorbed on these droplets, and the rest is expelled as micelles that coexist with the droplets. It is concluded that a PIC emulsification will always lead to a bimodal size distribution with surfactant "wasted" in small micelles. This is in contrast with the more efficient PIT emulsification.     

Synthesis of water and oil dual-absorption materials by bicontinuous microemulsion polymerization

Water and oil dual-absorption materials for application in oil well cement for self-healing micro creaks has been synthesized through bicontinuous microemulsion polymerization. Bicontinuous structure of microemulsion was used to implement the performance of absorbing both water and oil. Phase behavior of the microemulsion system was analyzed by “ε–β fish-shape phase diagram” from which middle phase line was obtained to provide the formula of polymerization. The product was characterized using scanning electron microscope (SEM), pore size distribution (BET), water/oil absorption rate test and water/oil absorption speed test. SEM analysis showed that neither water absorption component nor oil absorption component formed separated particles, while they formed continuous component respectively. Due to the bicontinuous structure and pores, the materials have fast water and oil absorption rate.     

Effect of Fiber Treatment on Dimensional Stability and Chemical Resistance Properties of Hybrid Composites

In this work, oil palm empty fruit bunch (EFB) and jute fibers were treated by 2-hydroxy ethyl acrylate (2-HEA) to enhance interaction with the epoxy matrix in hybrid composites. Hybrid composites were fabricated by the hand lay-up technique by reinforcing chemical-treated oil palm EFB and jute fibers in an epoxy matrix. Physical (density, void content, water absorption, and thickness swelling) and chemical resistance properties of treated hybrid composites were characterized. Chemically treated oil palm EFB/jute fiber reinforced hybrid composites display better dimensional stability (water absorption and thickness swelling) and chemical resistance as compared to untreated hybrid composites.     

Durable multifunctional superhydrophobic sponge for oil/water separation and adsorption of volatile organic compounds

Inspired by the strong adhesion of mussels, a super-hydrophobic sponge was designed and prepared by a simple and inexpensive one-pot solution immersion method. The prepared superhydrophobic sponge can not only efficiently separate the oil–water mixture, more importantly, but also remove volatile organic compounds in the atmospheric environment. Polydopamine (PDA) enables polydivinylbenzene (PDVB) particles to be firmly and tightly attached to the melamine sponge skeleton, thereby making the hydrophilic sponge superhydrophobic and providing adsorption sites for volatile organic compounds in the air. The synergy enables the sponge/PDA/PDVB to quickly adsorb oils and organic substances, and it has high stability and capacity even after 20 cycles. In addition, superhydrophobic sponges can still perform outstanding adsorption performance even under highly acidic and alkaline environments. Meanwhile, the static adsorption capacity of the sponge/PDA/PDVB for gaseous toluene is 5.7 times that of activated carbon. Compared with pure PDVB, the super-hydrophobic sponge in the dynamic experiment has a penetration time increased from 6 to 390 min, which is 65 times longer than that of the PDVB, and the adsorption performance has been greatly improved. Therefore, our strategy may achieve a new effect, which can quickly and easily separate oil–water mixtures and remove volatile gaseous pollutants, and it can provide potential options for practical applications

     

低黏附耐酸碱水相超疏油铜表面的制备

制备了一种新型的耐酸碱性的水相超疏油铜表面. 在水相中,油滴在其表面上的接触角高达162°,同时极易滚动,表明所得到的表面不但具有水相超疏油特性,同时还表现出较低的黏附性及较强的耐酸碱能力. 在不同pH值（2~12）的水溶液中,这种低黏附超疏油特性依然存在. 研究表明,该表面的水下超疏油及低黏附特性主要源于表面亲水性的化学组成及独特的微纳米等级结构之间的协同作用. 而较强的耐酸碱性则得益于铜材料自身较好的化学稳定性.     

Polyacrylonitrile/natural loofah sponge with spider web structure as a novel platform for enhanced oil adsorption

Three-dimensional, inexpensive and environmentally friendly adsorbent materials were urgently in demand for the absorption of organic compounds. In this study, the 3D ultralight sponge was assembled from fragmented electrospun nanofibers of polyacrylonitrile (PAN) and natural loofah. The PAN nanofibers and loofah short fibers were dispersed in an aqueous solution using polyvinyl alcohol (PVA) as the adhesive, and then formed the 3D ultralight sponge by freeze-drying technology. By adjusting the content of loofah, a kind of spider web structure which was beneficial to enhance oil adsorption was developed arising from polymers dissolution and reconstruction. At the same time, the loofah was integrated with the PAN by -OH···N≡C- hydrogen bonds to stabilize the structure. Finally, due to the high porosity (99.3%), low density (7.63 kg/m³) and unique spider web structure, our prepared PAN/loofah sponges could absorb organic compounds up to 177 times of their own weight. Hence, the developed PAN/loofah sponge as an environmentally friendly adsorbent would be promising in wastewater treatment.     

Design of a Waste Paper-Derived Chemically ‘Reactive’ and Durable Functional Material with Tailorable Mechanical Property Following an Ambient and Sustainable Chemical Approach

Controlled tailoring of mechanical property and wettability is important for designing various functional materials. The integration of these characteristics with waste materials is immensely challenging to achieve, however, it can provide sustainable solutions to combat relevant environmental pollutions and other relevant challenges. Here, the strategic conversion of discarded and valueless waste paper into functional products has been introduced following a catalyst-free chemical approach to tailor both the mechanical property and water wettability at ambient conditions for sustainable waste management and controlling the relevant environmental pollution. In the current design, the controlled and appropriate silanization of waste paper allowed to modulate both the a) porosity and b) compressive modulus of the paper-derived sponges. Further, the association of 1,4-conjugate addition reaction between amine and acrylate groups allowed to obtain an unconventional waste paper-derived chemically ‘reactive’ sponge. The appropriate covalent modification of the residual reactive acrylate groups with selected alkylamines at ambient conditions provided a facile basis to tailor the water wettability from moderate hydrophobicity, adhesive superhydrophobicity to non-adhesive superhydrophobicity. The embedded superhydrophobicity in the waste paper-derived sponge was capable of sustaining large physical deformations, severe physical abrasions, prolonged exposure to harsh aqueous conditions, etc. Further, the waste paper-derived, extremely water-repellent sponges and membranes were successfully extended for proof-of-concept demonstration of a practically relevant outdoor application, where the repetitive remediation of oil spillages has been demonstrated following both selective absorption (25 times) of oils and gravity-driven filtration-based (50 times) separation of oils from oil/water mixtures at different harsh aqueous scenarios.