Cellulose Composite Aerogels Research Articles

Cellulose/covalent organic framework aerogel for efficient removal of Cr(VI): Performance and mechanism study.

Cellulose composites have exceptional qualities, particularly in removing heavy metal ions. Nevertheless, these materials' poor mechanical qualities and the restricted exposure of surface-active sites reduce the effectiveness of their removal. The removal efficiency of adsorbent materials largely depends on their macroscopic structural characteristics. This study successfully developed a novel cellulose composite aerogel adsorbent (TBPM). TBPM aerogel possesses not only numerous active sites but also excellent mechanical strength. It is particularly suitable for the efficient removal of hexavalent chromium (Cr(VI))-containing wastewater. The aerogel exhibited a low density of 0.0238 g/cm3 and high porosity of 98.51 %. Incorporating the covalent organic framework (BT-Dg) increased the active sites in the composite aerogel, enhancing its adsorption performance. Compared with other common heavy metal ion adsorbents, the TBPM aerogel demonstrated superior removal performance, with a maximum adsorption capacity of 411.12 mg/g and a removal efficiency of 95.01 % in Cr(VI) solution at 15 °C, pH = 3. The adsorption of Cr(VI) followed pseudo-second-order kinetics and the Langmuir isotherm model. Even after seven adsorption-desorption cycles, TBPM aerogel maintained over 80 % removal efficiency. In addition, the TBPM aerogel successfully filtered 3439 mL of Cr(VI)-containing wastewater. This composite aerogel expands the application of cellulose composites in purifying wastewater.

Regenerated Cellulose/Lignin Composite Aerogel with Unique Toast‐Like Structure and Their Potential Applications in Thermal Camouflage

AbstractCamouflage clothing and cloaks are widely used in the military field. However, the widespread use of unmanned aerial vehicles (UAV) equipped with infrared thermal imaging devices has rendered traditional camouflage ineffective in the face of its unparalleled detection capabilities in modern warfare. Inspired by the enhancement principles of cellulose and lignin in natural wood, the interfacial engineering of biomineralization, and the scale structure of pangolins, herein, a regenerated cellulose/lignin composite aerogel with a toast‐like structure by integrating all three biomimetic techniques into a single biomimetic design is developed. The unique toast‐like structure allows effective protection of the internal porous structure during surface modification. The prepared composite aerogel not only exhibits excellent mechanical properties but also demonstrates a desert sand‐like color, superior thermal insulation, and effective infrared blocking capabilities, highlighting its potential in thermal camouflage applications. This work proposes a green method for preparing regenerated cellulose composite aerogel sheets, which is expected to provide a design concept for the preparation, functionalization, and application of regenerated cellulose aerogel materials. In addition, factors such as the generalizability of the study, environmental impacts, and economic benefits are discussed.

Robust fluorinated cellulose composite aerogels incorporating radiative cooling and thermal insulation for regionally adaptable building thermal management.

Passive radiative cooling (PRC) is an emerging sustainable technology that plays a key role for achieving the goal of carbon neutrality. However, several challenges remain for PRC materials in their practical application in building thermal management, including overcooling problems and unsatisfactory cooling efficiency caused by solar absorption and parasitic heat gains. In this work, fluorinated cellulose-based composite aerogels (FCCA) integrating thermal insulation and PRC were developed by a facile manufacturing strategy that combined phase separation and freeze-drying. P(VdF-HFP) was utilized to promote the formation of nano/micro porous architectures in FCCA, resulting in a decrease in the thermal conductivity of the aerogel to 0.034 W m-1 K-1 while simultaneously increasing its solar reflectance and infrared emissivity (8-13 μm) to 95.74 % and 97.15 %, respectively. The aerogel cooler achieved a sub-ambient cooling temperature of ~9.68 °C during the daytime and maintained its cooling effectiveness even on cloudy days. The fluorinated aerogels demonstrated excellent hydrophobicity and chemical durability after outdoor exposure and heat aging tests. This work opens up a new pathway to design low-cost cellulose-based materials for efficient thermal management of energy-saving buildings around the world.

Preparation of phosphorus-nitrogen synergistic flame retardant cellulose composite aerogel from waste cotton/phytic acid/acrylamide

Cellulose aerogel is a green and biodegradable material, but the high flammability of cellulose aerogel hinders its development. In order to expand the application range of cellulose aerogel, it is necessary to improve the flame retardancy of cellulose aerogel. In this paper, cellulose hydrogels were prepared by decolorizing waste cotton fabrics (WCF) and dissolving them in 1-butyl-3-methylimidazole chloride salt ([Bmim]Cl)/DMSO. The cellulose hydrogels were impregnated in aqueous phytic acid (PA)/acrylamide (AM) solution for a period of time and then heated and treated. A cellulose composite aerogel with excellent flame retardant properties was successfully prepared by using in situ polymerization. The results show that the cellulose composite aerogel has a porous structure and good thermal stability, and the residual carbon content in the air at 800 °C is >2.86 %. At the same time, it has excellent flame retardancy, the ultimate oxygen index (LOL) is >40, and the vertical combustion carbon length is <3.5 cm. The thermal insulation performance has also been improved, and the composite aerogel with a height of 1 cm has a temperature difference of 40.2 °C between the upper and lower surfaces on the 80 °C heating table.

Reusable superhydrophobic fluorinated cellulose-graphene composite aerogels for selective oil absorption

Although some progress had been made in the adsorption of graphene aerogels, more research was needed on their elasticity and recyclability. In this paper, a superhydrophobic fluorinated cellulose and graphene composite aerogel (FCGA) was prepared by a simple two-step impregnation method. Firstly, nano-cellulose was introduced into the graphene aerogel to inhibit the excessive accumulation of graphene lamellae and increase the specific surface area. The surface of the composite aerogel was then impregnated with silanol and fluorinated functional groups by a two-step impregnation method, resulting in a superhydrophobic aerogel with remarkable elasticity. The introduction of cellulose and silane provided the aerogel with excellent elasticity and recovery from cyclic adsorption. The successful grafting of the fluorophobic groups of PFDMS onto the graphene oxide strengthened the framework of the graphene aerogel, making FCGA a good candidate for repeated selective oil absorption. It could be restored to the original height after compression to 50% and 80% strain decompression. FCGA could efficiently absorb oil in water and had a high organic adsorption capacity. And the adsorption capacity of different oils/organic solvents reached 22,480 mg/g∼36,700 mg/g. Its absorption efficiency remained above 98.5% under distillation cycles. Due to its high elasticity, it retained more than 90% of its cyclic adsorption capacity through the squeeze cycle. As a simple, low-cost recovery method, its reusability was already better than most known adsorption elastic materials. The prepared composite aerogel had the advantages of simple preparation, low density (0.014 g/cm3), superhydrophobicity (water contact angle 153.3°), excellent adsorption properties, and recyclability. Therefore, FCGA had a very promising application in circulating selective oil absorption.

Preparation of hydrophobic and lipophilic carboxymethyl cellulose composite aerogel using ferrous ion/ persulfate and its directed oxidation for oil–water emulsion separation

In particular, efficient oxidative demulsification is an effective method for oil–water separation. However, the inactivation of free radicals owing to the rapid release of transition metals is the main factor that reduces the effectiveness. In this study, a hydrophobic and lipophilic CP/SiO2@Fe2+ composite aerogel was prepared using carboxymethyl cellulose as substrate, polyvinyl alcohol as reinforcement, and SiO2 nanoparticles as hydrophobic modifier. The resulting aerogel had a water contact angle of 139°, oil absorption yield of 99.9 %, higher specific surface area 132.13 m2·g−1, low density of 0.021 g·cm−3, and high porosity of 98.60 %. Fe2+ was slowly released from the composite aerogel after efficient Fe2+ loading of 65.77 mg·g−1. The drug exhibited a low release rate of 87.72 % after 9 h, which was higher than that of the composite aerogel. This promoted the efficient presence of SO4−· activated from persulfate oxidation in the catalytic oxidative demulsification system over a long period. The green and efficient separation of oily-water was achieved by the synergistic effect of the adsorption of the hydrophobic and lipophilic composite aerogel and targeted and efficient oxidative demulsification. These results demonstrate the advantages of high separation efficiency, durability, stability of the CP/SiO2@Fe2+ composite aerogel for oil–water separation.

In situ growth of HKUST-1 on electrospun polyacrylonitrile nanofibers/regenerated cellulose aerogel for efficient methylene blue adsorption

Dyes, as organic pollutants, are causing increasingly severe environmental problems. Metal-organic frameworks (MOFs) are considered promising dye adsorbents; however, their application is limited due to their powder or solid particle forms and limited reusability. Therefore, this study proposes an innovative approach to develop a novel MOF-based composite aerogel, specifically a HKUST-1/polyacrylonitrile nanofibers/regenerated cellulose (HKUST-1/PANNs/RC) composite aerogel adsorbent, for the adsorption of pollutants in water. This adsorbent was successfully prepared using a simple method combining covalent crosslinking, quick freezing, freeze-drying, in-situ growth synthesis, and solvothermal techniques. The HKUST-1/PANNs/RC composite aerogel exhibits a significantly large specific surface area, which is approximately 64 times greater than that of PANNs/RC (10.45 m2·g−1), with a specific surface area of 669.9 m2·g−1. The PANNs serve as a support framework, imparting excellent mechanical properties to the composite aerogel, enhancing its overall stability and recoverability. Additionally, the composite aerogel contains numerous -COOH and -OH groups on its surface, providing strong acid resistance and facilitating interactions with pollutant molecules through electrostatic interactions, π-π conjugation, n-π* interactions, and hydrogen bonding, thereby promoting the adsorption process. Using methylene blue (MB) as a probe molecule, the study results demonstrate that the HKUST-1/PANNs/RC composite aerogel has an adsorption capacity of 522.01 mg·g−1 for MB (25 h), exhibiting excellent adsorption performance. This composite aerogel shows great potential for application in water pollution control.

Polyurea–Cellulose Composite Aerogel Fibers with Superior Strength, Hydrophobicity, and Thermal Insulation via a Secondary Molding Strategy

Polyurea–Cellulose Composite Aerogel Fibers with Superior Strength, Hydrophobicity, and Thermal Insulation via a Secondary Molding Strategy

Facile synthesis of a 3D magnetic graphene oxide/Fe3O4/banana peel-derived cellulose composite aerogel for the efficient removal of tetracycline.

Many initiatives have incorporated graphene oxide (GO) and biomass into aerogels for wastewater treatment. We report on the facile fabrication of a magnetic GO/Fe3O4/banana peel-derived cellulose (bio-cellulose) aerogel using an ultrasound-assisted mechanical mixing method and freeze-drying technique for the removal of tetracycline (TC). The component materials and composite aerogel were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen adsorption-desorption analysis, and vibrating sample magnetometry (VSM). The effects of solution pH and adsorbent dose on the adsorption performance of the synthesized adsorbents were investigated. The adsorption behavior at the equilibrium of the GO/Fe3O4/bio-cellulose aerogel was studied and analyzed using four well-known non-linear models: Langmuir, Freundlich, Sips, and Temkin. The results showed that the experimental data fitted well with the Freundlich and Sips isotherm models. The maximum adsorption capacity achieved from the Sips model was 238.7 mg g-1. The adsorption kinetics were studied and proved to follow the Elovich kinetic model with an initial rate of 0.89 g g-1 min-1. These results confirm the favorable adsorption of TC on the heterogeneous surface that exhibits a wide range distribution of adsorption energies of the desired GO/Fe3O4/bio-cellulose aerogel. The experimental findings demonstrate that the aerogel possesses the notable features of environmental friendliness, cost-effectiveness, and comparatively high TC adsorption capacity. Therefore, utilizing biomass to develop the structure of the magnetic GO-based composite aerogel is significantly promising for antibiotic-containing wastewater treatments.

Recycling Coal Fly Ash for Super-Thermal-Insulating Aerogel Fiber Preparation with Simultaneous Al2O3 Extraction.

A large quantity of coal fly ash is generated worldwide from thermal power plants, causing a serious environmental threat owing to disposal and storage problems. In this work, for the first time, coal fly ash is converted into advanced and novel aerogel fibers and high-purity α-Al2O3. Silica-bacterial cellulose composite aerogel fibers (CAFs) were synthesized using an in situ sol-gel process under ambient pressure drying. Due to the unique "nanoscale interpenetrating network" (IPN) structure, the CAFs showed wonderful mechanical properties with an optimum tensile strength of 5.0 MPa at an ultimate elongation of 5.8%. Furthermore, CAFs with a high porosity (91.8%) and high specific surface area (588.75 m2/g) can inherit advanced features, including excellent thermal insulation, stability over a wide temperature range, and hydrophobicity (contact angle of approximately 144°). Additionally, Al2O3 was simultaneously extracted from the coal fly ash to ensure that the coal fly ash was fully exploited. Overall, low-cost woven CAFs fabrics are suitable for wearable applications and offer a great approach to comprehensively use coal fly ash to address environmental threats.

Cellulose/nanocarbon composite based multifunctional aerogels for thermal management

Renewable resource-based aerogels have attracted numerous attention due to the requirement on sustainable multifunctional materials for thermal management. A series of cellulose and nanocarbon composite aerogels have been prepared from a blend of carboxylated cellulose nanofibril (CCNF) with carbon nanotube (CNT), graphene oxide (GO), or carbon fiber (CF) using directional freezing method. CCNF/nanocarbon aerogels from bidirectional freezing exhibit higher compression strength due to bridge structures that are induced by temperature gradient horizontally and vertically. Meanwhile, CCNF/carbon aerogels from bidirectional freezing also have thermal conductivity coefficient (λ) as low as 0.0308 W/(m·K), which increases to 0.0388 W/(m·K) after calcination. The dispersed linear carbon materials CF and CNT in CCNF matrix lead to thermoelectric, Joule heating and photothermal performance of CCNF/nanocarbon aerogels, which is also promoted by calcination. The Seebeck coefficient of CCNF/nanocarbon aerogels ranges from 0.027 to 0.067 mV/K and change into 0.037–0.044 mV/K due to the more uniform carbon network formed after high temperature treatment. A 5–15 V input voltage can induce a temperature increase of 62 ∼ 303 °C for composite aerogel after calcination. A laser with 0.3 W power can result in a rapid temperature increase even to 200 °C in seconds for composite aerogel with and without calcination. These kinds of CCNF/nanocarbon based composite aerogels exhibit ability in thermal management, including thermal insulation, thermoelectric, electric and photo induced heating, which are good candidates for multifunctional aerogels.

Efficient Solar Desalination of Seawater Using a Novel Carbon Nanotube-Based Composite Aerogel.

Solar desalination of seawater is an effective approach to address the scarcity of freshwater resources. For solar steam generation, it is critical to design biodegradable, sustainable, low-cost, and high-evaporation-rate technology. This study aims to develop a novel solar desalination technology by designing and fabricating a nanocomposite material with excellent light absorption and thermal conversion properties. We designed a double-layer aerogel structure, which uses naturally abundant carboxymethyl cellulose (CMC) as the basic skeleton to achieve sustainability and biodegradability, and uses carbon nanotubes as the photothermal material for efficient light absorption to prepare a ferric tannate/carbon nanotube/carboxymethyl cellulose composite aerogel (FT-CNT-CMC aerogel). Experimental results demonstrate that the FT-CNT-CMC aerogel exhibits a high light absorption rate of 96-98% within the spectral range of 250-2400 nm, showcasing remarkable photothermal conversion performance. Under a sun intensity of 1 kW·m-2, the FT-CNT-CMC aerogel achieves a significant evaporation rate of 1.942 kg·m-2·h-1 at room temperature. Moreover, the excellent performance of the FT-CNT-CMC aerogel is validated in practical seawater desalination and organic dye wastewater purification. The FT-CNT-CMC aerogel exhibits a retention rate exceeding 99% for Na+, Mg2+, K+, and Ca2+ ions in simulated seawater, while no characteristic absorption peaks are observed in methylene blue and rhodamine B dye solutions after purification. These findings highlight the promising potential of the FT-CNT-CMC aerogel in the field of novel solar desalination, providing a viable solution to obtain freshwater.

Bacterial cellulose composite aerogel with high elasticity and adjustable wettability for dye absorption and oil–water separation

Recently, cellulose-based biomass aerogel, as a high performance adsorption material, has received considerable attention. However, it remains a huge challenge to prepare cellulose aerogels with outstanding mechanical properties by simple and environmentally-friendly strategies. Here, we describe a green one-pot method to prepare a versatile bacterial cellulose/γ-(2,3-epoxypropoxy) propytrimethoxysilane trimethoxysilane composite aerogel (BK aerogel). The elasticity of BK aerogel is significantly improved and up to 96.4% after compression under 80% strain. Further, the elastic recovery can reach 87.8% over 50 times compressions at a set strain of 80 %, implying the obtained composite aerogel possesses strong fatigue resistance. BK aerogel could be soaked in water to adsorb cationic dyes and reused without being damaged. In addition, the prepared BK aerogel is rich in hydroxyl and epoxy groups, so its surface chemistry can be further adjusted. Taking hydrophobic modification as an example, the prepared aerogel can be used for oil–water separation and reused by mechanical squeezing. This study paves a simple and green solution for developing high elastic cellulose nanofiber aerogel with adjustable surface chemistry to meet diverse applications.

Preparation of Microcrystalline Cellulose/N-(2-aminoethyl)-3- Aminopropyl Methyl Dimethoxysilane Composite Aerogel and Adsorption Properties for Formaldehyde.

Air pollution is related to the development of the national economy and people's livelihoods. Formaldehyde, as one of the main pollutants in the air, affects people's physical and mental health. In order to remove formaldehyde and better protect the health of residents, it is necessary to develop efficient adsorption materials. In this study, APMDS-modified cellulose composite aerogel microcrystalline was investigated. The adsorption of formaldehyde by the MCC/APMDS (Microcrystalline Cellulose/N-(2-aminoethyl)-3- Aminopropyl Methyl Dimethoxysilane) composite aerogel mainly relied upon the reaction of the protonated -NH3+ group in APMDS with formaldehyde to form a Schiff base to achieve the effect of deformaldehyde. Meanwhile, the modification of the aerogel reduced the pore volume and specific surface area, and the average pore size increased to 14.56 nm, which enhanced the adsorption capacity of formaldehyde, and the adsorption amount reached 9.52 mg/g. This study provides valuable information for the preparation of adsorbent materials with high formaldehyde adsorption capacity for air purification.

Application Progress of Cellulose Aerogel Modified by GMA

Cellulosic aerogels have attracted much attention because of their low density, high porosity and low thermal conductivity in many modified composite materials. Glycidyl methacrylate (GMA) is a new type of polymeric monomer with low cost, low toxicity, good biocompatibility, and easy chemical modification that has emerged in recent years, and it was widely used in the modification of rubber, fiber and other polymer materials. Cellulose composite aerogel, which is constructed by using GMA as a bridge to connect other materials, has rich functionality and shows great application potential in biomedicine, catalysis, adsorption and other fields. In this paper, the classification and properties of aerogels and cellulose are briefly described at first, then the synthesis methods of cellulose aerogels are introduced, and the applications of composite aerogels synthesized from cellulose modified by GMA in various fields in recent years are reviewed. This paper reviews the application of GMA-modified cellulose composite aerogels about the heavy metal and dye adsorption, biological tissues, wound dressings, drug carriers, biosensor and catalytic carriers. Finally, the future development prospect and current limitations of GMA modified cellulose aerogel are briefly introduced.

Micron down feather fibers reinforced cellulose composite aerogel with excellent acoustic and thermal insulation

Micron down feather fibers reinforced cellulose composite aerogel with excellent acoustic and thermal insulation

Stable and Salt-Resistant Janus Evaporator Based on Cellulose Composite Aerogels from Waste Cotton Fabric.

Solar steam generation has been considered a promising approach for using renewable solar energy to produce clean water from seawater and wastewater. It shows great potential for alleviating water shortages. However, salt accumulation and system longevity are challenges which impede the widespread use of evaporators. This paper reports a stable Janus evaporator with thickness controllable hydrophilic and hydrophobic layers based on cellulose composite aerogels, which were extracted from waste cotton fabric by a two-step freeze-drying process. The obtained glutaraldehyde cross-linked carbon nanotubes/cellulose Janus aerogel exhibited an attractive solar steam generation rate of 1.81 kg·m-2·h-1 and a light-to-vapor efficiency of up to 92.5% in 1 sun illumination. Moreover, the Janus solar steam generator could pledge stable and sustainable solar-driven water evaporation performance within a 10 h test, showing a high salt-resistant property in simulated seawater. In addition, the developed solar evaporator also had a good purification effect on dye wastewater. These findings suggest its potential ability for seawater desalination and wastewater purification.

Preparation and properties of down feather fibers reinforced cellulose composite aerogel

Preparation and properties of down feather fibers reinforced cellulose composite aerogel

Novel Layered Double Hydroxides@carboxymethyl Cellulose Composite Aerogel Towards Co(II) Absorption

Cobalt (Co) ion is a common heavy metal ion and the main metal ion in nuclear wastewater. However, the study on the absorption for Co(II) is not sufficient. Herein, a novel ES-layered double hydroxide (LDH) is prepared by intercalated ethylenediaminetetraacetic acid disodium salt (EDTA) and sodium dodecylbenzene sulfonate (SDBS) in a magnesium, iron pristine LDH, which is subsequently used for ES-LDH@carboxymethyl cellulose (CMC) composite aerogel. The results of Fourier transform infrared spectroscopy, X-ray diffraction spectra and thermogravimetric analysis shows successfully preparation of intercalated LDH. The pore morphology, specific surface area and pore size distribution of the composite aerogels are characterized by scanning electron microscope and Nitrogen-BET curves. The significantly improved adsorption capacity, adsorption kinetics and isotherms the absorbents on Co(II) are systematically revealed. This study thus provides an important understanding and path for dealing with the threat of Co(II).

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance in removal of fluoroquinolone antibiotics from water

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance in removal of fluoroquinolone antibiotics from water