SiO2改性聚丙烯纤维棉对油水乳状液的高效分离

利用纳米SiO2颗粒对聚丙烯(PP)纤维棉进行了亲(疏)水改性,构建了系列不同润湿性和粗糙度的PP纤维棉,探究了不同孔隙度和表面能的PP纤维棉对W/O及O/W型乳状液的分离性能.结果表明,经过亲(疏)水改性的PP纤维棉对水/正己烷和水/甲苯乳状液的分离效率都高于99.5％,分离通量高于700 L/(m2·h),并针对不同形式油-水乳状液阐释其相应的分离机制,为后续油-水乳状液分离材料的科学设计和可控制备提供了理论依据.     

改性聚丙烯材料对餐饮废水的油水分离特性研究

为进一步提高聚丙烯材料在餐饮废水分离器中油水分离的效果,通过将聚丙烯材料在K2Cr2O7-H2SO4溶液中进行单面液相氧化改性,得到具有单面亲水特性的改性聚丙烯材料。对聚丙烯材料改性的反应条件进行优选,并与未改性聚丙烯材料进行分离效果对比。结果表明,改性聚丙烯材料表面羰基和羟基亲水集团明显增多,当反应条件为70℃、25 min时,聚丙烯表面的接触角最大减小31.67%;分离器适宜的条件为体积流量为(150±10)L/h、聚丙烯板角度为15°、温度为50℃,此时改性聚丙烯材料的除油率和COD去除率比未改性分别提高11.7个和13.2个百分点。     

复合聚丙烯板在油水分离中的应用

采用化学改性处理的方法，使聚丙烯表面覆盖一层氧化薄膜，从而改善聚丙烯的亲水性。基于聚丙烯本身良好的亲油性，开发出两表面分别具有良好亲油、亲水性能的复合型聚丙烯板。这种复合型聚丙烯板应用于聚结板式油水分离器，迎合了油水分离机理，强化了油水分离过程。实验结果表明，复合聚丙烯聚结板使油水分离器的分离效率提高了25％，分离器的处理能力提高了40％。     

改性废弃口罩熔喷布疏水膜的制备及油水分离性能

通过原位化学沉积在废弃口罩熔喷布表面负载均匀分散的二氧化硅(SiO₂)纳米颗粒，进而接枝十八烷基三氯硅烷(OTS)，得到具有多级粗糙结构的疏水膜。改性膜的水接触角达到142.5°，重力作用下四氯化碳通量达到12224L·m^-2·h^-1，油水分离效率大于98%。结果表明改性膜能够在酸性、碱性、盐溶液以及超声等条件下保持性能稳定，具有很好的应用前景,为废弃口罩的绿色、低碳、资源化利用提供了新思路。     

聚丙烯亲水改性最新进展

简要介绍了聚丙烯材料的亲水性测试方法,着重论述了对聚丙烯材料进行亲水改性的各种方法及最新研究进展,并指出今后对聚丙烯材料进行亲水改性的发展方向.     

漆酚与Fe3O4协同超疏水改性三聚氰胺海绵用于高效油水分离

含油污水对生态环境造成了极大破坏,油水分离已成为亟待解决的环保难题。为了解决油水分离问题,通过简单浸涂法将纳米Fe₃O₄和漆酚协同修饰于两亲性三聚氰胺海绵(MS)表面,改性所得漆酚-Fe₃O₄-漆酚三聚氰胺海绵(UFeU-MS)材料实现了海绵基底从超亲水-超亲油到超疏水-超亲油的转换。由于漆酚含有邻苯二酚基团与15～17碳长烷基链,一方面使用一定浓度漆酚将Fe₃O₄与海绵进行黏附;另一方面借助长烷基链降低海绵表面能。通过对UFeU-MS进行表征分析验证,其表面水接触角高达160.9°±1.8°,满足超疏水-超亲油的要求;吸收有机溶剂和油类物质的质量大于其自身的21倍,10次吸附-解吸循环分离效率可以保持在97.77%;经不同pH溶液浸泡水接触角可以保持在147°以上,也适应于酸碱环境的油水分离。饱和吸附后的海绵既可经过简单的物理挤压回收溶剂,也可通过外加磁场远程回收。     

用于油水分离的三维疏水材料的制备及研究进展

疏水性改性三维材料在油水分离等领域有着重要作用。本文总结了用于油水分离三维材料的种类及研究进展,并对其未来发展进行了展望。     

聚丙烯共混改性对其聚结除油性能的影响

采用不同性质的添加剂(CPB、CTAB、PVDF、硅蜡和长链烷基硅油)对聚丙烯进行共混改性,研究了不同改性剂对聚丙烯材料表面亲油亲水性的影响,以及改性材料在油水分离过程中的聚结除油性能。结果表明,除PVDF外,同样添加量下的不同改性剂,或同一添加剂的不同添加量,改性聚丙烯的亲水角和亲油角之差越小,越有利于聚丙烯聚结除油性能的提高;由于PVDF的疏水疏油性,有利于改性材料表面油膜的流动、脱落,以及水中油滴的聚结,其对除油效率的提高要明显高于其它的改性剂。     

油水分离材料的制备及应用

采用电化学沉积法,以金属铜网为基底,制备出具有油水分离性能的网膜。研究发现,相比于超疏水-超亲油性铜网,超亲水-水下超疏油性铜网不但制备过程简单,而且还具有油水分离速度快、分离效果好和可多次重复使用的特点。     

Application of mullite-zeolite-alumina microfiltration membranes coated by SiO2 nanoparticles for separation of oil-in-water emulsions

The main objective of this work is the manipulation of hydrophilic materials in support, intermediate and selective layer to synthesize a novel nano-tubular ceramic membrane for treatment of oily wastewater. First, porous mullite-alumina-zeolite composite membranes were prepared by an extrusion method. Changes in porosity, pore size, shrinkage, and mechanical strength of the support membranes were investigated as function of percentage composition and sintering temperature in order to obtain the optimal conditions. According to the results, the most favorable condition set was determined to be a support membrane with a weight percent of 50, 30, and 20 for mullite, alumina, and zeolite, respectively, and a porosity of 38%, a pore size of 0.39 µm, and a shrinkage of 10.2% sintered at 1250 °C and with good mechanical properties at 24.6 MPa. The cross-flow filtration technique was employed to coat the natural zeolite on the inner surface of the support membrane to achieve a narrower pore size distribution. Finally, a thick layer of nano-SiO₂ was coated on the membrane by utilizing the dip-coating method to develop a hydrophilic membrane while avoiding defects. Moreover, scanning electron microscopic (SEM) analysis of the SiO₂ membranes showed that the natural zeolite and nano-SiO₂ layer is homogeneous and demonstrates high adhesion to the support membrane. Besides, the result of COD rejection showed that the SiO₂ membranes have an undeniable capability in rejection of oil droplets with a reasonable permeation flux. Therefore, the obtained membranes are highly promising for practical applications and environmental remediation in sensitive Persian Gulf zone.     

Recycling of waste attapulgite to prepare ceramic membranes for efficient oil-in-water emulsion separation

Large-scale application of ceramic membranes is restricted by high cost resulting from raw materials and sintering process. In this study, low-cost ceramic membranes were prepared with waste attapulgite (WAT) and α-Al₂O₃ as starting materials and used for oily wastewater treatment. The optimal membrane sintered at 1100 °C possessed excellent properties, with open porosity of 41.6%, flexural strength of 37.2 MPa and average pore size of 0.40 μm. The membrane also displayed outstanding permeability and chemical stability. The hydrophilicity and underwater oleophobicity were enhanced after surface modification. When used for oil-in-water emulsion filtration, the permeate flux reached 236.8 L m^?2 h^?2 bar^-1 under a low transmembrane pressure of 0.2 bar and the oil rejection exceeded 99%. Membrane cleaning with a simple ultrasonic treatment could easily achieve flux recovery. This study proposed a feasible strategy for both solid waste utilization and oily wastewater treatment.     

The effect of bubble size on oil-water separation efficiency for a novel oil-water separation column

Bubble size is a key factor in froth flotation for oil-water separation. In this paper, the bubble size which impacts on oil removal efficiency for a novel oil-water separation column was researched systematically. The bubble size distribution was researched by using the photographic method and Matlab software. In addition, several operating parameters which impact on the bubble size were investigated, including circulating pressure, aeration rate, and the foaming agent. Based on the results of experimental data and image analysis, the frother consumption and aeration rate has important influence on the bubble size. The bubble size can be controlled by adjusting the operation conditions including the circulating pressure, aeration rate, and the frother consumption. The optimum operating conditions for the oil-water separation column were determined. Furthermore, the mathematical model of oil removal efficiency for the oil-water separation column was established.     

Fabrication of magnetically responsive anti-fouling and easy-cleaning nanofiber membrane and its application for efficient oil-water emulsion separation

The magnetically responsive anti-fouling nanofiber membrane(MRANM) was fabricated for efficient oilwater emulsion separation,which could be cleaned using oscillating magnetic field.MRANM was prepared by grafting superparamagnetic Fe₃O₄ nanoparticles onto the surface of electrospun polyacrylonitrile nanofiber membrane(PANM),Compared with PANM,the water contact angle of MRANM decreased from 104° to 0°,indicating that the hydrophilicity of the membrane was significantly improv...     

Synthesis and characterization of mullite-ZrO2 porous fibrous ceramic for highly efficient oil-water separation

This work aimed to proposing a new strategy for preparing the mullite-ZrO₂ porous fibrous ceramic used as alternative matrix material for oil-water separation by the aqueous gel-casting method. The properties of the fabricated porous fibrous ceramics in terms of microstructure, phase composition, apparent porosity, bulk density and compressive strength were investigated and the separation behavior was predicted by analyzing the structural changes. It is demonstrated that the phase composition of green bodies consisted of bayerite, boehmite, ZrSiO₄ and YSZ, and the sintered sample contained mullite, ZrO₂ and YSZ. As the YSZ fibers increased, the porosity of the fabricated porous ceramic increased with the maximum value of 70.65% due to the formation of more pores caused by YSZ fibers. Moreover, a significant increase in compressive strength (up to 9.52–21.86 MPa) was observed with the increase of YSZ fibers. Therefore, the fabricated porous ceramics could be appropriative for advanced applications of separation membranes for oil-water separation.     

Synthesis and characterization of superoleophobic fumed alumina nanocomposite coated via the sol-gel process onto ceramic-based hollow fibre membrane for oil-water separation

Oily wastewater treatment is a global challenge due to the substantial amount of effluent resulted from many industrial and domestic activities. To overcome the challenge of using existing treatment approach and fouling, superoleophobic coatings were fabricated. In this study, a superoleophobic membrane surface was obtained using the sol-gel technique with perfluorooctanoate (PFO), poly (diallyl dimethylammonium chloride) (PDADMAC), and nanoparticles as complex-polymer nanocomposites. The effects of coating cycles on the surface structure, chemical properties, surface chemistry, and oleophobicity of the surface were examined using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and oil contact angle measurement. The results showed that the coated layer successfully adhered to the substrate surface. However, the chemical stability with respect to oil contact angle (OCA) revealed a decline at pH 7 and pH 9 and maintained stability at pH 3. Besides, oil flux at 63.0 L/m². h was achieved for PDADMAC-Al₂O₃/44 wt% PFO and the highest separation efficiency of 98% was obtained. Furthermore, the oil rejection decreases as the oil concentration increases from 1 to 3 g/L. OCA of 155° was obtained after 5 coating cycles. Apart from mitigating substrate fouling, the superoleophobic and superhydrophilic coating can be applied to a ceramic-based hollow fibre membrane and efficiently used for the separation of oil from oily wastewater.     

Coalescence separation of oil water emulsion on amphiphobic fluorocarbon polymer and silica nanoparticles coated fiber-bed coalescer

Discharging untreated oily wastewater into the environment disrupts the ecological balance, which is a global problem that requires urgent solutions. Superhydrophilic and superoleophilic fibrous medium(FM) effectively separated oil–water emulsion as it was hydrophobic underwater. But its separation efficiencies(SEs) first increased to 98.9%,then dropped to 97.6% in 10 min because of oil-fouling. To tackle this problem, FM deposited with 0%–10% silica nanoparticle(NPsFMs), then coated by fluorocarbon polymer(X-[CH_2CH_2O]_nCH_2CH_2O-Y-NH-COOCH_2C_4F_9)(FCNPs FMs), was used to enhance its roughness and regulate its initial wettability to improve the anti-fouling property. FCFM and FCNPs FMs were hydrophobic and oleophobic in air and oleophobic underwater. Their water contact angles, oil contact angles and oil contact angles were 115.3°–121.1°, 128.8°–136.5°, and 131.6°–136.7°, respectively,meeting the requirement of 90°–140° for coalescence separation. FCNPs FM-5 had the best separation performance with a constant value of 99.8% in 10 min, while that of FCNPs FM-10 slightly decreased to 99.5%. Theoretical released droplet(TRD) diameter, calculated by the square root of the product of pore radius and fiber diameter, was used for the evaluation of coalescence performance. Analyzed by two ideal models, TRD diameter and fiber diameter showed a parabola type relationship, proving that the separation efficiency was a collaborative work of wettability, pore size and fiber diameter. Also, it explained the SEs reduction from FCNPs FM-5 to FCNPs FM-10 was revelent to the three parameters. Moreover, FCNPsFMs effectively separated emulsions stabilized by cationic surfactant CTAB(SEs:97.3%–98.4%) and anionic surfactant SDBS(SEs: 91.3%–93.4%). But they had an adverse effect on nonionic surfactant Tween-80 emulsion separation(SEs: 94.0%–71.76%). Emulsions made by diverse oils can be effectively separated:octane(SEs: 99.4%–100%), rapeseed oil(SEs: 97.3%–98.8%), and diesel(SEs: 95.2%–97.0%). These findings provide new insights for designing novel materials for oil–water separation by coalescence mechanism.     

Multifunctional fly ash-based GO/geopolymer composite membrane for efficient oil-water separation and dye degradation

Membrane fouling and separation materials with low cost and high efficiency are challenges for membrane separation technology in wastewater treatment. Superhydrophilic and underwater superoleophobic membranes show broad application prospects in oily wastewater treatment because of their high permeability, selectivity, and antifouling performance; however, they are generally ineffective for organic pollutant molecules. In this study, a novel graphene oxide (GO)/geopolymer composite membrane with superhydrophilic and underwater superoleophobic characteristics was prepared by dipping a mixed slurry of GO and fly ash-based geopolymer onto a stainless steel mesh via a facile self-assembly process. The results show that GO could adjust the hydrophilicity and water flux of composite membranes. The composite membrane containing 0.4 wt% GO (4GO/GCM) had the best hydrophilic, water flux of 1363 kg/(m²·h), and high separation efficiencies (≥98.2%) for oil-water mixtures and oil-in-water emulsions under gravity-driven. In addition, the 4GO/GCM sample exhibited excellent stability under harsh conditions, including hot water and strong acid, alkali, and salt solutions. Importantly, the sample derived from fly ash exhibited unique photocatalytic degradation performance for organic dye molecules under simulated solar-light irradiation. Thus, it is believed to this strategy has substantial potential for high-value utilization of fly ash and the sustainable treatment of oily and dye wastewater.     

A facile method to functionalize engineering solid membrane supports for rapid and efficient oil–water separation

A facile and low-cost method is developed to functionalize engineering metal membrane supports, such as stainless steel (SS), with epoxy-containing polymer poly(glycidyl methacrylate) (PGMA) to produce a versatile and universal platform for subsequent surface modification. With a PGMA anchoring layer, we have demonstrated that hydrogel particles, such as polyacrylamide-co-poly(acrylic acid) (PAM-co-PAA), can be subsequently grafted to form functional polymer membranes for rapid and efficient oil–water separation. By contact angle and AFM measurement, we have confirmed that PAM-co-PAA hydrogel particle layer grafted on a PGMA-modified SS surface exhibits excellent selectivity as required for liquid–liquid separation, showing high affinity to water but not to oils as an ideal membrane for oil–water separation. To evaluate the separation efficiency, a simple flow-through device is employed to separate free-floating oil from water in the mixture of varied initial oil volume fraction and oil composition. Under substantially high pump flow rate up to 1.3 L/min, PAM-co-PAA hydrogel treated SS mesh can achieve excellent separation efficiency with less than 5% oil or water in the respective filtrate at the flux of as high as 540 m³/(m²·h) and retentate at the flux of 1.95 m³/(m²·h). This separation efficiency is better than, or comparable to, the maximal performance achieved using conventional gravity methods at much lower flow rate. Similar approach could be also adapted to graft superhydrophobic and superoleophilic polymer membranes with PGMA-treated engineering support to separate water from oil.