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Nowadays, oil pollution has become more serious, which causes great threats both to the ecological environment and human life. In this study, a novel type of multifunctional deacetylated cellulose acetate/polyurethane (d-MCA:MTPU) composite nanofiber membranes for oil/water separation are successfully fabricated by electrospinning, which show super-amphiphilicity in air, super-hydrophilicity in oil, and oleophobicity in water. All the d-MCA:MTPU composite nanofiber membranes with different mass ratios can be used as water-removing, oil-removing, and emulsion separation substance only by gravity driving force. The highest separation flux for water and oil reaches up to 37 000 and 74 000 L m−2 h−1, respectively, and all the separation efficiencies are more than 99%. They have outstanding comprehensive mechanics performance, which can be controlled by simply adjusting the mass ratios. They show excellent antifouling and self-cleaning ability, endowing powerful cyclic stability and reusability. Those results show that d-MCA:MTPU composite nanofiber membranes have great application prospects in oil/water separation. 相似文献
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With the increase of industrialization and urbanization, humankind faces massive oil-based pollution due to tanker accidents, human error, and natural disasters. For this, hydrophobic sorbents are fabricated and their applications for the removal of oil from polluted water sources are investigated. These hydrophobic sorbents are prepared by the condensation reaction of poly(dimethylsiloxane) and tris[3-(trimethoxysilyl)propyl]isocyanurate cross-linker via bulk polymerization. The obtained sorbents exhibit high oil sorption capacity, fast absorption–desorption kinetics, and great reusability. Moreover, they can selectively absorb oil from the water surface, thus making them practical for water clean-up applications. 相似文献
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In this work, the longitudinal permeability of squarely packed dual-scale fiber preforms is studied theoretically. These fiber preforms are composed of aligned porous tows and the tows are tightly packed. The effective permeability is calculated as a parallel-like network of intra-tow permeability and inter-tow permeability, which are quantified by Darcy’s law and the inscribed radius between tows, respectively. The jump velocity at the interface between inter-tow fluids and porous tows is considered, as derived by substituting Beavers and Joseph’s correlation into Brinkman’s equation. We further examine the effects of intra-tow permeability on the effective permeability of the fibrous system with three interface conditions: (1) interface velocity = 0, (2) interface velocity = mean intra-tow velocity, and (3) interface velocity = jump velocity. The jump-velocity-based model is found to be closest to numerical data. The influence of the fiber volume fraction of tows on the effective permeability is also analyzed. 相似文献
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《Ceramics International》2020,46(5):5610-5622
A simple with cost-effective method in the production and fabrication of graphene-based rubber nanocomposites as electrode materials is still remain a global challenge. In this work, we proposed one- and two-step approaches to fabricate an exfoliated graphene oxide (GO) as nanofiller in three different types of rubber latex polymer, namely, low ammonia natural rubber latex (NRL), radiation vulcanized NRL (RVNRL), and epoxy NRL 25 (ENRL 25). The electrical conductivity and capacitive behavior of nanocomposite samples were investigated under a four-point probe and cyclic voltammetry measurements, respectively. Meanwhile, the morphological properties were observed using field emission scanning electron microscopy, energy dispersive X-ray, optical polarization microscope, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. The thermal stabilities of the nanocomposites were also investigated by thermogravimetric analysis. Among all, the GO/RVNRL polymer nanocomposite samples performed a better homogeneity with an improved electrical conductivity (~8.6 × 10−4 Scm−1) as compared with the GO/ENRL 25 (~3.1 × 10−4 Scm−1) and GO/NRL (~2.6 × 10−4 Scm−1) polymer nanocomposite samples. In addition, the GO/RVNRL polymer nanocomposite electrodes showed acceptable specific capacitance (5 Fg-1). The successfully fabricated conductive GO-based rubber nanocomposites are suitable for new supercapacitor electrodes. 相似文献
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在厌氧条件下研究了西南地区一种典型土壤微生物芽孢杆菌Bacillus sp.dwc-2对模拟地下水中U(Ⅵ)的还原行为,重点考察了时间、无机阴离子、腐殖酸(HA)及富里酸(FA)对还原的影响,并利用TEM、EDS、SAED和XPS对还原后的样品进行了表征。结果表明:在pH=7.0、cNaHCO3=5 mmol/L和T=303 K条件下,Bacillus sp.dwc-2对U(Ⅵ)的还原率随时间的增加而增加,24 h内最大还原率为12.2%,此后则随时间的增加逐渐降低;HA和FA对U(Ⅵ)的微生物还原行为有一定影响,其中HA和FA浓度为25 mg/L时,U(Ⅵ)的还原在24 h最明显,其还原率分别为14.2%和16.2%,但随着HA和FA浓度的继续增加,因在U(Ⅵ)离子与HA、FA形成的配合物表面形成致密的腐殖层,抑制了电子的转移,阻止了U(Ⅵ)的还原。此外,研究表明HCO3-也会抑制U(Ⅵ)的还原。TEM-SAED和XPS分析证实了还原过程中U(Ⅳ)的存在。上述结果可为真实环境中微生物还原U(Ⅵ)提供基础数据和参考。 相似文献