Controlling porosity and density of nanocellulose aerogels for superhydrophobic light materials

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 145-153 ◽  
Author(s):  
Chengua Yu ◽  
Feng Wang ◽  
Shiyu Fu ◽  
Lucian Lucia
Keyword(s):  
Contact Angle ◽  
Freeze Drying ◽  
Engine Oil ◽  
High Porosity ◽  
Water Mixture ◽  
Waste Engine Oil ◽  
Hydrophobically Modified ◽  
Static Contact ◽  
Oil Water ◽  
Hydrophobic Material

A very low-density oil-absorbing hydrophobic material was fabricated from cellulose nanofiber aerogels–coated silane substances. Nanocellulose aerogels (NCA) superabsorbents were prepared by freeze drying cellulose nanofibril dispersions at 0.2%, 0.5%, 0.8%, 1.0%, and 1.5% w/w. The NCA were hydrophobically modified with methyltrimethoxysilane. The surface morphology and wettability were characterized by scanning electron microscopy and static contact angle. The aerogels displayed an ultralow density (2.0–16.7 mg·cm-3), high porosity (99.9%–98.9%), and superhydrophobicity as evidenced by the contact angle of ~150° that enabled the aerogels to effectively absorb oil from an oil/water mixture. The absorption capacities of hydrophobic nanocellulose aerogels for waste engine oil and olive oil could be up to 140 g·g-1 and 179.1 g·g-1, respectively.

scholarly journals Hydrophobically modified cotton fabric assisted separation of oil-water mixture

2021 ◽  
Author(s):  
Neha Bhatt ◽  
Abhilasha Mishra ◽  
Rekha Goswami
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Particle Size ◽  
Free Energy ◽  
Cotton Fabric ◽  
Water Mixture ◽  
Mixture Separation ◽  
Oil Water ◽  
Scanning Electron

Abstract Superhydrophobic-superoleophilic fabrics were prepared and evaluated for oil-water mixture separation efficiencies. The nano-TiO2 and nano- SiO2 based coatings were done on the surface of the cotton fabric to create nanoscale roughness over the surface which was further modified by low energy material 1, 1, 3, 3- Hexamethyldisilazane (HMDS) and, polydimethylsiloxane (PDMS). Particle size and stability of prepared sol were characterized by particle size analysis and zeta potential. Coated cotton fabric samples were characterized by contact angle, contact angle hesteresis and surface free energy for its hydrophobic nature. Surface morphology was studied by scanning electron microscopy (SEM). The coated fabrics were found hydrophobic with low surface free energy values. The maximum contact angle was found 133° and lowest contact angle hysteresis was 5°. Scanning electron microscopy (SEM) confirmed the appearance of nanoscale surface roughness after coating of sols on cotton fabric. The average particle size and zeta potential values of silica sol was 61 nm and 137 mv whereas for titania sol it was found 344 nm and 200 mv respectively. The oil/water separation efficiency of coated fabric was also observed by different oil-water mixture. The coatings were found hydrophobic in nature and seem to be very useful for water/oil mixture separation.

scholarly journals Preparation of Parabolic Superhydrophobic Material for Oil-Water Separation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1914 ◽  
Author(s):  
Xiaoying Qiao ◽  
Chunyan Yang ◽  
Qian Zhang ◽  
Shengke Yang ◽  
Yangyang Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Carbon Tetrachloride ◽  
Separation Efficiency ◽  
Contact Angles ◽  
Engine Oil ◽  
Water Droplets ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water ◽  
Copper Mesh

In order to prepare parabolic superhydrophobic materials, copper meshes were used as the substrate and ultrasonic etching and oxidative corrosion were carried out with FeCl3 solution and H2O2 solution, respectively, and then the surface was modified with stearic acid (SA). The topological structure and surface wettability of the prepared mesh were characterized by fluorescence microscope, scanning electron microscopy and contact angle measurement. Finally, the as-prepared copper meshes were applied to oil-water separation. The results showed that the micro-nano-mastoid structure on the surface of the copper mesh was flaky bulges, forming a rough structure similar to a paraboloid. When the oxidative corrosion time of H2O2 was 1 min, it is more beneficial to increase the hydrophobicity of the surface of the copper mesh and increase the contact angle of water droplets on the surface of the membrane. Additionally, based on superhydrophobic materials of the parabolic copper mesh, the static contact angles of the water droplets, engine oil and carbon tetrachloride with the surface were approximately 153.6°, 5° and 0.1°, respectively and the sliding angle of the water droplets with the surface were approximately 4.9°. The parabolic membrane was applied to discuss the separation efficiency of different oils with deionized water and the separation efficiency was obtained as benzene > carbon tetrachloride > oil > machine oil. Therefore, based on the research, the parabolic superhydrophobic material has good efficiency of oil-water separation.

Evaluation of Modified Poly by UV-Induced Graft Polymerization as a Novel Hydrophilic Films

2013 ◽  
Vol 815 ◽  
pp. 594-598
Author(s):  
Bing Qiang Wang
Keyword(s):  
Contact Angle ◽  
Original Film ◽  
Graft Polymerization ◽  
Irradiation Time ◽  
Film Surface ◽  
Ferrous Ammonium Sulfate ◽  
Water Mixture ◽  
Static Contact ◽  
Ferrous Ammonium ◽  
Grafting Degree

In order to improve the hydrophilic performances, the surface of poly films was modified through grafting polymerization of styrene (ST) initiated by ultraviolet (UV) in ethanol/water mixture solution. The effects of irradiation time, concentration of inhibitor (ferrous ammonium sulfate) on the grafting degree of ST will be investigated. The original and grafted poly films were characterized by scanning electron microscopy (SEM) and Static contact angle (CA), to characterize the chemical changes of the poly film surface. The results showed that the hydrophilic of poly films was improved significantly than that of the original film. The contact angle of PO-g-ST increased from 70° to 120.4° over a critical grafting degree of 26.35%, the hydrophilic of PP membranes improved dramatically.

scholarly journals Preparation and Application of Superhydrophobic Copper Mesh by Chemical Etching and In-situ Growth

2021 ◽  
Vol 9 ◽  
Author(s):  
Qilei Tong ◽  
Zhenzhong Fan ◽  
Biao Wang ◽  
Qingwang Liu ◽  
Yunhe Bo ◽  
...  
Keyword(s):  
Contact Angle ◽  
Chemical Etching ◽  
Separation Efficiency ◽  
Water Mixture ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water ◽  
Copper Mesh

Oily sewage and floating oil in the ocean post a huge threat to the ecological environment, therefore, developing an efficient separation for oil/water mixtures is an urgent need. Currently, superhydrophobic materials exhibit excellent oil/water separation ability. In this study, a superhydrophobic copper mesh prepared by the chemical etching method and the in-situ growth method and the performance evaluation are introduced. The oxide layer on the surface of the copper mesh is first removed by pickling, and then immersed in FeCl3 solution for chemical etching to make the surface rough, stearic acid (SA) is used for in-situ growth to reduce the surface energy, a superhydrophobic oil-water separation copper mesh is obtained. The water contact angle (WCA) of the copper mesh is more than 160°. The copper mesh is chemically stable and can effectively adsorb floating oil and separate the oil-water mixture. After several oil-water separation experiments, the oil-water separation efficiency can still be above 98%. The effects of the concentration of FeCl3 and SA on the contact angle and oil-water separation efficiency are investigated, the results show that when the concentration of FeCl3 is 2% and SA is 1.5%, the WCA and oil-water separation efficiency are the largest. The research used a simple and environmentally friendly method to prepare the oil-water separation copper mesh, which has important application significance for water quality restoration.

scholarly journals Sustainable, Highly Efficient and Superhydrophobic Fluorinated Silica Functionalized Chitosan Aerogel for Gravity-Driven Oil/Water Separation

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 66
Author(s):  
Zhongjie Zhu ◽  
Lei Jiang ◽  
Jia Liu ◽  
Sirui He ◽  
Wei Shao
Keyword(s):  
Separation Efficiency ◽  
Dimensional Structure ◽  
Separation Performance ◽  
High Porosity ◽  
Water Mixture ◽  
Water Separation ◽  
Highly Efficient ◽  
Oil Water Separation ◽  
Gravity Driven ◽  
Oil Water

A superhydrophobic fluorinated silica functionalized chitosan (F-CS) aerogel is constructed and fabricated by a simple and sustainable method in this study in order to achieve highly efficient gravity-driven oil/water separation performance. The fluorinated silica functionalization invests the pristine hydrophilic chitosan (CS) aerogel with promising superhydrophobicity with a water contact angle of 151.9°. This novel F-CS aerogel possesses three-dimensional structure with high porosity as well as good chemical stability and mechanical compression property. Moreover, it also shows striking self-cleaning performance and great oil adsorption capacity. Most importantly, the as-prepared aerogels exhibits fast and efficient separation of oil/water mixture by the gravity driven process with high separation efficiency. These great performances render the prepared F-CS aerogel a good candidate for oil/water separation in practical industrial application.

scholarly journals Biomimetic Approach for the Elaboration of Highly Hydrophobic Surfaces: Study of the Links between Morphology and Wettability

Biomimetics ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Quentin Legrand ◽  
Stephane Benayoun ◽  
Stephane Valette
Keyword(s):  
Contact Angle ◽  
Ginkgo Biloba ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Textured Surfaces ◽  
Replication Process ◽  
Wetting Behavior ◽  
Static Contact ◽  
Biomimetic Approach ◽  
Highly Hydrophobic

This investigation of morphology-wetting links was performed using a biomimetic approach. Three natural leaves’ surfaces were studied: two bamboo varieties and Ginkgo Biloba. Multiscale surface topographies were analyzed by SEM observations, FFT, and Gaussian filtering. A PDMS replicating protocol of natural surfaces was proposed in order to study the purely morphological contribution to wetting. High static contact angles, close to 135∘, were measured on PDMS replicated surfaces. Compared to flat PDMS, the increase in static contact angle due to purely morphological contribution was around 20∘. Such an increase in contact angle was obtained despite loss of the nanometric scale during the replication process. Moreover, a significant decrease of the hysteresis contact angle was measured on PDMS replicas. The value of the contact angle hysteresis moved from 40∘ for flat PDMS to less than 10∘ for textured replicated surfaces. The wetting behavior of multiscale textured surfaces was then studied in the frame of the Wenzel and Cassie–Baxter models. Whereas the classical laws made it possible to describe the wetting behavior of the ginkgo biloba replications, a hierarchical model was developed to depict the wetting behavior of both bamboo species.

scholarly journals Mechanism of active silica nanofluids based on interface-regulated effect during spontaneous imbibition

2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Oil Recovery ◽  
Dynamic Contact Angle ◽  
Liquid Interface ◽  
Spontaneous Imbibition ◽  
Wettability Alteration ◽  
Low Permeability ◽  
Oil Water ◽  
Solid Liquid

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.

scholarly journals Fabrication of silica/PVA-co-PE nanofiber membrane for oil/water separation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuanli Chen ◽  
Hui Fan ◽  
Xinlin Zha ◽  
Wenwen Wang ◽  
Yi Wu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Silicone Oil ◽  
Hydroxyl Groups ◽  
Water Mixture ◽  
Silica Nanospheres ◽  
Nanofiber Membrane ◽  
Water Separation ◽  
Oil Water Separation ◽  
Silica Nanostructures ◽  
Oil Water

AbstractHigh efficiency and anti-pollution oil/water separation membrane has been widely explored and researched. There are a large number of hydroxyl groups on the surface of silica, which has good wettability and can be used for oil-water separation membranes. Hydrophilic silica nanostructures with different morphologies were synthesized by changing templates and contents of trimethylbenzene (TMB). Here, silica nanospheres with radical pores, hollow silica nanospheres and worm-like silica nanotubes were separately sprayed on the PVA-co-PE nanofiber membrane (PM). The abundance of hydroxyl groups and porous structures on PM surfaces enabled the absorption of silica nanospheres through hydrogen bonds. Compared with different silica nanostructures, it was found that the silica/PM exhibited excellent super-hydrophilicity in air and underwater “oil-hating” properties. The PM was mass-produced in our lab through melt-extrusion-phase-separation technique. Therefore, the obtained membranes not only have excellent underwater superoleophobicity but also have a low-cost production. The prepared silica/PM composites were used to separate n-hexane/water, silicone oil/water and peanut oil water mixtures via filtration. As a result, they all exhibited efficient separation of oil/water mixture through gravity-driven filtration.

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