scholarly journals Anisotropic Cellulose Nanofibers/Polyvinyl Alcohol/Graphene Aerogels Fabricated by Directional Freeze-drying as Effective Oil Adsorbents

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 712 ◽  
Author(s):  
Lijie Zhou ◽  
Shengcheng Zhai ◽  
Yiming Chen ◽  
Zhaoyang Xu
Keyword(s):  
Polyvinyl Alcohol ◽  
Freeze Drying ◽  
High Efficiency ◽  
Cellulose Nanofibers ◽  
High Strength ◽  
Dip Coating ◽  
High Porosity ◽  
Water Contact ◽  
Water Separation ◽  
Composite Aerogel

Under the current situation of frequent oil spills, the development of green and recyclable high-efficiency oil-absorbing aerogel materials has attracted wide attention from researchers. In this study, we report a high-strength, three-dimensional hydrophobic cellulose nanofiber (CNF)/polyvinyl alcohol (PVA)/graphene oxide (GO) composite aerogel with an anisotropic porous structure, which was fabricated by directional freeze-drying technology using anisotropically grown ice crystals as a template, followed by hydrophobic treatment with a simple dip coating process. The prepared composite aerogel presented anisotropic multi-level pore microstructures, low density (17.95 mg/cm3) and high porosity (98.8%), good hydrophobicity (water contact angle of 142°) and great adsorption capacity (oil absorption reaching 96 times its own weight). More importantly, the oriented aerogel had high strength, whose compressive stress at 80% strain reached 0.22 MPa and could bear more than 22,123 times its own weight without deformation. Therefore, the CNF/PVA/GO composite aerogel prepared by a simple and easy-to-operate directional freeze-drying method is a promising absorbent for oil-water separation.

scholarly journals Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil–water separation

2018 ◽  
Vol 9 ◽  
pp. 508-519 ◽  
Author(s):  
Zhaoyang Xu ◽  
Huan Zhou ◽  
Sicong Tan ◽  
Xiangdong Jiang ◽  
Weibing Wu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Vinyl Alcohol ◽  
Cellulose Nanofibers ◽  
Carbon Aerogels ◽  
Poly Vinyl Alcohol ◽  
High Porosity ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

With the worsening of the oil-product pollution problem, oil–water separation has attracted increased attention in recent years. In this study, a porous three-dimensional (3D) carbon aerogel based on cellulose nanofibers (CNFs), poly(vinyl alcohol) (PVA) and graphene oxide (GO) was synthesized by a facile and green approach. The resulting CNF/PVA/GO aerogels were synthesized through an environmentally friendly freeze-drying process and then carbonized to yield CNF/PVA/GO carbon aerogels with low density (18.41 mg cm−3), high porosity (98.98%), a water contact angle of 156° (super-hydrophobic) and high oil absorption capacity (97 times its own weight). The carbonization treatment of the CNF/PVA/GO aerogel not only improved the hydrophobic properties but also enhanced the adsorption capacity and specific surface area. Given the many good performance characteristics and the facile preparation process of carbon aerogels, these materials are viable candidates for use in oil–water separation and environmental protection.

scholarly journals Polydopamine Induced Wettability Switching of Cellulose Nanofibers/n-Dodecanethiol Composite Aerogels

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Runan Gao ◽  
Ying Shang ◽  
Peng Jiao ◽  
Yue Jiao ◽  
Jian Li ◽  
...  
Keyword(s):  
Cellulose Nanofibers ◽  
Absorption Capacity ◽  
Water Mixture ◽  
The Novel ◽  
Water Contact ◽  
Water Separation ◽  
Composite Aerogel ◽  
Composite Aerogels ◽  
Oil Water Separation ◽  
Oil Water

The novel wettability switchable cellulose nanofiber- (CNF-) based aerogel was conveniently prepared by polydopamine mediated composition of CNF and n-dodecanethiol. The wettability of aerogels can be controlled by adjusting the PDA and n-dodecanethiol loading content, which leads to a variation of water contact angle from 0-149°. The PDA was coated on cellulose nanofibers via hydrogen bonds and then n-dodecanethiol was anchored onto the scaffolds by Michael addition reaction, which was revealed by XPS and FTIR spectra. The composite aerogel can selectively absorb a series of oily liquids from the oil/water mixture, with the maximum absorption capacity of 68 g/g. This work presented a facile strategy to prepare wettability switchable CNF-based heterogenous aerogel and exhibited the potential of the composite aerogel for oil/water separation.

scholarly journals Complex Aerogels Generated from Nano-Polysaccharides and Its Derivatives for Oil–Water Separation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1593 ◽  
Author(s):  
Hajo Yagoub ◽  
Liping Zhu ◽  
Mahmoud H. M. A. Shibraen ◽  
Ali A. Altam ◽  
Dafaalla M. D. Babiker ◽  
...  
Keyword(s):  
Guar Gum ◽  
Corn Oil ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

The complex aerogel generated from nano-polysaccharides, chitin nanocrystals (ChiNC) and TEMPO-oxidized cellulose nanofibers (TCNF), and its derivative cationic guar gum (CGG) is successfully prepared via a facile freeze-drying method with glutaraldehyde (GA) as cross-linkers. The complexation of ChiNC, TCNF, and CGG is shown to be helpful in creating a porous structure in the three-dimensional aerogel, which creates within the aerogel with large pore volume and excellent compressive properties. The ChiNC/TCNF/CGG aerogel is then modified with methyltrichlorosilane (MTCS) to obtain superhydrophobicity/superoleophilicity and used for oil–water separation. The successful modification is demonstrated through FTIR, XPS, and surface wettability studies. A water contact angle of 155° on the aerogel surface and 150° on the surface of the inside part of aerogel are obtained for the MTCS-modified ChiNC/TCNF/CGG aerogel, resulting in its effective absorption of corn oil and organic solvents (toluene, n-hexane, and trichloromethane) from both beneath and at the surface of water with excellent absorption capacity (i.e., 21.9 g/g for trichloromethane). More importantly, the modified aerogel can be used to continuously separate oil from water with the assistance of a vacuum setup and maintains a high absorption capacity after being used for 10 cycles. The as-prepared superhydrophobic/superoleophilic ChiNC/TCNF/CGG aerogel can be used as a promising absorbent material for the removal of oil from aqueous media.

scholarly journals Analysis of Superhydrophobic-Superoleophilic Properties on Modification of Polyurethane Sponge for Selective Oil-Water Separation

2021 ◽  
Vol 4 (1) ◽  
pp. 52-62
Author(s):  
Niken Aprilia Eka Putri ◽  
Arif Tjahjono ◽  
Perdamean Sebayang
Keyword(s):  
Separation Efficiency ◽  
Average Pore Size ◽  
Dip Coating ◽  
Absorption Capacity ◽  
Average Pore ◽  
Water Contact ◽  
Water Separation ◽  
Coating Methods ◽  
Oil Water Separation ◽  
Polyurethane Sponge

In this research, a modification of polyurethane (PU) sponge material has been made to obtain superhydrophobic-superoleophilic properties. The PU sponge was coated with several nanomaterials such as ZnO, Fe3O4+TEOS, and stearic acid by dip-coating and drop-coating methods. The tests include selective separation of oil and water with a magnetic response. Several types of oil and organic solvents were tested for absorption capacity. The results showed that the PU@ZnO@Fe3O4@SA sponge has a good absorption capacity, from 4.37 mL to 7.37 mL. The fabricated PU sponge could selectively separate oil from water with a separation efficiency above 99%. The fabricated PU sponge also could be magnetically driven by external magnetic fields. From the characterization using 3D OM, the water contact angle was 153.38°, which indicates that the PU@ZnO@Fe3O4@SA sponge is superhydrophobic. And from surface morphology obtained an average pore size diameter of 167.475 μm.

scholarly journals Nanocellulose Xerogel as Template for Transparent, Thick, Flame-Retardant Polymer Nanocomposites

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3032
Author(s):  
Wataru Sakuma ◽  
Shuji Fujisawa ◽  
Lars A. Berglund ◽  
Tsuguyuki Saito
Keyword(s):  
Polymer Composites ◽  
Flexural Modulus ◽  
Cellulose Nanofibers ◽  
High Strength ◽  
High Porosity ◽  
Load Bearing ◽  
Surface Areas ◽  
Reinforced Composite ◽  
Reinforcing Fillers ◽  
The Matrix

Cellulose nanofibers (CNFs) have excellent properties, such as high strength, high specific surface areas (SSA), and low coefficients of thermal expansion (CTE), making them a promising candidate for bio-based reinforcing fillers of polymers. A challenge in the field of CNF-reinforced composite research is to produce strong and transparent CNF/polymer composites that are sufficiently thick for use as load-bearing structural materials. In this study, we successfully prepared millimeter-thick, transparent CNF/polymer composites using CNF xerogels, with high porosity (~70%) and high SSA (~350 m2 g−1), as a template for monomer impregnation. A methacrylate was used as the monomer and was cured by UV irradiation after impregnation into the CNF xerogels. The CNF xerogels effectively reinforced the methacrylate polymer matrix, resulting in an improvement in the flexural modulus (up to 546%) and a reduction in the CTE value (up to 78%) while maintaining the optical transparency of the matrix polymer. Interestingly, the composites exhibited flame retardancy at high CNF loading. These unique features highlight the applicability of CNF xerogels as a reinforcing template for producing multifunctional and load-bearing polymer composites.

scholarly journals Facile Fabrication of Superhydrophobic Cross-Linked Nanocellulose Aerogels for Oil–Water Separation

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 625
Author(s):  
Qianqian Shang ◽  
Jianqiang Chen ◽  
Yun Hu ◽  
Xiaohui Yang ◽  
Lihong Hu ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
High Porosity ◽  
Water Contact ◽  
Water Separation ◽  
Cellular Microstructure ◽  
Oil Water Separation ◽  
Facile Fabrication ◽  
Oil Water

A facile and environmental-friendly approach was developed for the preparation of the cross-linked nanocellulose aerogel through the freeze-drying process and subsequent esterification. The as-prepared aerogel had a three-dimensional cellular microstructure with ultra-low density of 6.05 mg·cm−3 and high porosity (99.61%). After modifying by chemical vapor deposition (CVD) with hexadecyltrimethoxysilane (HTMS), the nanocellulose aerogel displayed stable super-hydrophobicity and super-oleophilicity with water contact angle of 151°, and had excellent adsorption performance for various oil and organic solvents with the adsorption capacity of 77~226 g/g. Even after 30 cycles, the adsorption capacity of the nanocellulose aerogel for chloroform was as high as 170 g/g, indicating its outstanding reusability. Therefore, the superhydrophobic cross-linked nanocellulose aerogel is a promising oil adsorbent for wastewater treatment.

scholarly journals Novel Cellulose Nanofibers/Polyvinyl Alcohol/Polyethyleneimine Nanoparticle for Cu2+ Removal in Water

2021 ◽  
Author(s):  
Rongrong Si ◽  
Chaojun Wu ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
Ronggang Li
Keyword(s):  
Polyvinyl Alcohol ◽  
Freeze Drying ◽  
Removal Rate ◽  
Cellulose Nanofibers ◽  
Drying Method ◽  
Order Model ◽  
Bending Vibration ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Structurally Stable

Abstract In this study, environmentally friendly CNF/PVA/PEI nanoparticle was obtained by assembling PEI (polyethyleneimine) into CNF/PVA aerogels, which were prepared by freeze-drying method with the help of glutaraldehyde. FTIR results showed that PEI likely assembled into the CNF/PVA aerogel due to appearances of bending vibration of the CNF/PVA/PEI nanoparticle at 1615cm− 1. BET results further demonstrated that PEI have successfully assembled into aerogel since the specific surface area (22.93m2/g) of CNF/PVA/PEI nanoparticle was lower than that (56.37m2/g) of CNF/PVA aerogel. SEM results also showed that PEI could obviously regulate the morphology of CNF/PVA aerogel. TGA indicated that CNF/PVA/PEI nanoparticle was structurally stable at 216.4°C. The adsorption kinetics of the CNF/PVA/PEI nanoparticle for Cu2+ removal presented good correlations with the Pseudo-second-order model. The adsorption and desorption results showed that the removal rate of 2g/L CNF/PVA/PEI nanoparticle for Cu2+in water could reach more than 93% when the concentration of Cu2+ ranged from 20 to 80mg/L in one hour, and it could still retain more than 80% after 3 cycles.

scholarly journals Synthesis of a Superhydrophobic Polyvinyl Alcohol Sponge Using Water as the Only Solvent for Continuous Oil-Water Separation

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Junyong Chen ◽  
Junhui Xiang ◽  
Xian Yue ◽  
Huaxin Li ◽  
Xianbo Yu
Keyword(s):  
Contact Angle ◽  
Polyvinyl Alcohol ◽  
Separation Efficiency ◽  
Water Contact ◽  
Water Separation ◽  
Long Term Stability ◽  
Static Water ◽  
Oil Water Separation ◽  
Oil Water

Few cases of hydrophobic materials synthesized in water have been reported. In this work, water, as the only solvent, is used to prepare a superhydrophobic sponge via a facile and environment-friendly route. The as-prepared sponge, namely silylated polyvinyl alcohol (PVA) sponge, exhibits superhydrophobic and superoleophilic characters. It has the static water contact angle (WCA) of 152 ± 1 and the static oil contact angle (OCA) of 0°, which can lead to excellent selectivity for oil-water separation. Besides, the methyltriethoxysilane (MTES) can form a stable mixed structure with the PVA skeleton, resulting in the rare shedding of polymethylsiloxane nanoparticles and the long-term stability for oil-water separation. Furthermore, the silylated sponge shows a high separation efficiency (>99.6%), removing oil up to 6200∼14000 times of its own mass. The findings demonstrated that the silylated superhydrophobic sponge can be a promising candidate in water treatment application.

Ultra-robust Superhydrophobic/superoleophilic Stainless Mesh Coated by PTFE/SiO2 for Oil/water Separation

MRS Advances ◽  
2018 ◽  
Vol 4 (07) ◽  
pp. 359-367 ◽  
Author(s):  
Chaolang Chen ◽  
Ding Weng ◽  
Awais Mahmood ◽  
Jiadao Wang
Keyword(s):  
Contact Angle ◽  
Self Assembly ◽  
High Efficiency ◽  
Water Contact ◽  
Water Separation ◽  
Low Surface Energy ◽  
Assembly Method ◽  
Potential Applications ◽  
Oil Water Separation ◽  
Oil Water

AbstractIn this study, a superhydrophobic and superoleophilic stainless mesh coated with polytetrafluoroethylene/silicon dioxide (PTFE/SiO2) was fabricated through electrostatic self-assembly method followed by sintering treatment. The PTFE was utilized to construct low-surface-energy surface and the SiO2 nanoparticles were added to enhance its surface roughness. The as-prepared stainless mesh exhibited desirable superhydrophobicity and superoleophilicity with a water contact angle of 152° and oil contact angle of 0°. The coated stainless mesh could separate a variety of oil/water mixtures with high efficiency and it also exhibited good recyclability. Moreover, the corrosion-resistance of stainless mesh was greatly improved by coating it with PTFE. The thermogravimetric analysis (TGA) measurements showed that the coated mesh could withstand high temperature of up to 430°C, indicating excellent thermal-resistance. It is believed that this ultra-robust stainless mesh would have significant potential applications in industry.

Sign in / Sign up

Export Citation Format

Share Document