Hydrophobic Cellulose Aerogel Research Articles

Fabrication of Hydrophobic Cellulose Aerogels from Renewable Biomass Coir Fibers for Oil Spillage Clean-Up

Fabrication of Hydrophobic Cellulose Aerogels from Renewable Biomass Coir Fibers for Oil Spillage Clean-Up

Preparation and adsorption properties of magnetic hydrophobic cellulose aerogels based on refined fibers

A novel approach was introduced to prepare very low density, highly porous, economic, reusable, hydrophobic, and magnetic cellulose aerogels from hardwood dissolving pulp via a simple freeze-drying procedure. The aerogels showed outstanding adsorption efficiency for several oils and organic solvents and demonstrated excellent selectivity for absorbing oil from an oil/water mixture. Moreover, they were easily collected by an external magnet, indicating excellent recyclability and reusable for at least 10 cycles while still retaining supreme adsorption capacity (up to 181 g/g for silicone oil). This study proposes an economic and novel method for the large-scale preparation of hydrophobic and magnetic cellulose aerogels, making them a promising candidate for the efficient and sustainable cleaning of oils and chemical spills.

Facile and novel ambient pressure drying approach to synthesis and physical characterization of cellulose-based aerogels

In this study, highly porous and ultralight cellulose aerogel (CA) was successfully synthesized via a novel and facile ambient pressure drying technique. In this drying method, naphthalene (NPH) as the porous-making agent occupied space between cellulose fibers and controlled structural collapse and severe shrinkage of samples successfully. By sublimation of NPH crystals at the end of procedure, ultimate CA was obtained. This technique can be considered as a fast, safe and cost-effective drying method. CA samples illustrated appropriate physical characteristics including: low densities (0.058 g cm−3), high porosity (> 96.5%), low thermal conductivity (0.0417 W m−1 K−1), appropriate mechanical strength and negligible shrinkage (< 10%) during the drying procedure. hydrophobic cellulose aerogel (HCA) and carbonized cellulose aerogel (CCA) were also obtained and the oil/water separation efficiency of these samples were investigated. Contact angle test reveled highly hydrophobicity with angle equal to 137° and 126° for HCA and CCA, respectively. Investigation of oils and organic solvents adsorption capacity illustrated that samples adsorbed oils and organic solvents in range from 1200 to 1800% of their weight. Regeneration ability of HCA and CCA was studied in five cycles. Depending on type of adsorbate, regeneration study showed various regeneration capacity from 30 to 98%.

A hydrophobic cellulose aerogel from coir fibers waste for oil spill application

In this work, a hydrophobic cellulose aerogel was successfully developed from coir fibers waste. The hydrophobic aerogel was prepared using a simple sol-gel and freeze-drying method followed by surface modification using either trimethylchlorosilane (TMCS) or hexamethyldisilazane (HMDS). The operating temperature was varied around the boiling point of the modifying agent ranging from 50-70°C for TMCS and 110-130°C for HMDS. The concentration of modification agents was varied from 40-60 wt.% in n-Hexane. The best condition in term of its hydrophobicity was obtained at 50% of TMCS with a temperature of 60°C and 40% of HMDS at 120°C. The obtained aerogel has a good hydrophobic characteristic indicated by a high of water contact angle of 100-150°C. The aerogel also could selectively absorb only oil from the mixture of oil-water. Therefore, it could be the promising material used to overcome the oil spill issue due to its biodegradability, abundant availability, and low cost.

Hydrophobic cellulose aerogel from waste napkin paper for oil sorption applications

Abstract This study is the first, to the best of our knowledge, where waste napkin paper was successfully valorized to low-density (27.2 mg cm−3) cellulose aerogels for oil sorption material. Two simple methods with different gel coagulators, ethanol and sulfuric acid, were used for preparation of the aerogel. Conditions for the alkaline treatment of the raw material and the pre-freezing temperature in the lyophilization process were optimized. It was found that the water and oil sorption capacities of the aerogels were not significantly affected by alkaline treatment, while they could be adjusted by changing the pre-freezing temperature. Although the produced aerogels were initially amphiphilic, hydrophobic surfaces were obtained by vapor deposition of methyltrimethoxysilane (MTMS) and these materials possessed high sorption capacities, up to 32.24 cm3 g−1 (28.56 g g−1) for pump oil and 26.77 cm3 g−1 (39.59 g g−1) for chloroform. This was comparable to aerogels prepared from fresh cellulosic materials via the sol-gel method, as their sorption capacities varied in the range of 14–45 g g−1.

Preparation and Characterization of Cellulose Grafted with Epoxidized Soybean Oil Aerogels for Oil-Absorbing Materials.

The absorbent materials synthesized from biosources with low cost and high selectivity for oils and organic solvents have attracted increasing attention in the field of oil spillage and discharge of organic chemicals. We developed a convenient surface-grafting method to prepare efficient and recyclable biobased aerogels from epoxidized soybean oil (ESO)-modified cellulose at room temperature. The porous network-like structure of the cellulose aerogel was still fully retained after undergoing hydrophobic modification with ESO. Moreover, the modified aerogels possessed excellent hydrophobicity with a water contact angle of 132.6°. Moreover, the absorbent ability of the hydrophobic cellulose aerogels was systematically assessed. The results showed that modified aerogels could retain more than 90% absorption capacity even after 30 absorption-desorption cycles, indicating that the ESO-grafted cellulose aerogels have practical applications in the oil-water separation from industrial wastewater and oil-leakage removal.

Nanocomposite of hydrophobic cellulose aerogel/graphene quantum dot/Pd: synthesis, characterization, and catalytic application.

Novel hydrophobic cellulose aerogel (CA) supported graphene quantum dots (GQD)/Pd were synthesized with high lipophilicity, superior porosity as well as high catalytic activity. The nanocomposite aerogel was obtained in four steps, including transformation of cotton to CA, a silanization reaction of CA in the presence of TiO2 nanoparticles to give polysiloxane/TiO2 nanoparticles supported on CA (ST@CA), a modification of ST@CA with GQD to yield polysiloxane/TiO2 nanoparticles/graphene quantum dots supported on CA (STG@CA), and finally a deposition of Pd nanoparticles on STG@CA. The synthesized aerogel demonstrated hydrophobicity with a water contact angle of 136.2°. It also exhibited excellent oil/water selective absorption capacity with an oil absorption of up to 79 g g−1 with 134 g g−1 selectivity. Finally, the nanocomposite was used as a heterogeneous catalyst in the oxidation reaction of alcohols, ethylbenzene, and alkenes. High yields, excellent selectivities, green and mild reaction conditions, recyclability and biocompatibility of the catalyst were important features of the reactions.

Low-Cost, Sustainable, and Environmentally Sound Cellulose Absorbent with High Efficiency for Collecting Methane Bubbles from Seawater

The use of natural materials to solve environmental problems is intended to decrease the burden on the global environment. In this paper, we describe a natural, repeatable, and low-cost method for terminating methane bubbles under water before they release into the atmosphere. A cellulose aerogel with porous structure and large surface area was fabricated via combining a dry pulp disintegration process with freeze-drying. The aerogel became superhydrophobic after it was modified with methyltrimethoxysilane (MTMS); therefore, it was able to effectively collect and store transport methane bubbles under water. The hydrophobic cellulose aerogel (HCA) exhibited exceptional performance for collecting methane bubbles under both static and dynamic absorption-release conditions. We hope this work will inspire alternative methods for the exploitation and elimination of environmental methane with the potential to alleviate global warming.

Highly compressible ultra-light anisotropic cellulose/graphene aerogel fabricated by bidirectional freeze drying for selective oil absorption

Low density aerogels are promising materials for oil absorption, but they typically suffer from low compressibility and elasticity. Herein, three-dimensional (3D) highly compressible, elastic, anisotropic, cellulose/graphene aerogels (CGAs) were prepared by bidirectional freeze drying. After the grafting of long carbon chains through chemical vapor deposition, the modified cellulose/graphene aerogels (MCGA) gained superhydrophobicity. The synergistic effects of flexible cellulose, stiff graphene, and the special bidirectionally aligned porous structure gave MCGA outstanding compression and recoverability properties. MCGA was able to recover 99.8% and 96.3% when compressed to 60% and 90% strain, respectively. Due to its ultra lightweight (bulk density of 5.9 mg/cm3) and high surface area (47.3 m2/g), MCGA possesses a remarkable absorption capacity of 80–197 times its weight, which surpasses all hydrophobic cellulose aerogels and most carbon-based aerogels. Furthermore, the high elasticity of MCGA facilitates fast and efficient recovery of the absorbed oil by simple mechanical squeezing, and ensures excellent performance stability over repeated use. The high compressibility and high oil recovery ability though mechanical squeezing has never been achieved by other aerogels. Hence, MCGA can serve as a promising super absorbent material for selective oil absorption and recovery.