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Nowadays high porosity aerogels are widely applied in wastewater purification, while the fragility and unversatility of nascent cellulose aerogels limited the application in oil/water filtering separation. Here, highly compressible, elastic, superhydrophobic cellulose/poly(vinyl alcohol) (PVA) composite aerogels were fabricated via combination of chemical cross-linking, freeze drying and silanization. The obtained cellulose/PVA aerogels exhibited durable superhydrophobicity with WCA of 156.6 °, even maintaining 155.0 ° after 30 days. Synergistic effects of physical entanglement, chemical cross-linking and H-bond network between cellulose and PVA molecular chains endowed the aerogels with excellent compressibility and recoverability. The aerogels exhibited maximum compressive stress of 490.7 kPa at 90% strain, even without reduction in mechanical strength under 70% compressive strain for 10 cycles. More importantly, the strengthened aerogels exhibited remarkable separation performances for both immiscible oil/water mixtures and surfactant-stabilized water-in-oil emulsions. Fascinating permeation flux of up to 7176.3 L m−2 h−1 and total separation amount as high as 4550.6 L m−2 with separation efficiency of 98.5% for water-in-cyclohexane emulsion were harvested. Thus, this work provides a green, sustainable and mass-producible cellulose-based aerogel for high-efficiency oily wastewater remediation. [ABSTRACT FROM AUTHOR]

The primary purpose of cold weather clothing is to shield the wearer from the extremities of the external environment. The thermal properties of nanofibers and their potential applications have tremendous scope and application in this area. The objective of this study was to investigate the mechanisms of heat transfer through fibrous insulation where the fiber diameter was less than 1 μm. Electrospinning process was used to produce flexible polyurethane and polyvinylidene fluoride nanofibers embedded with silica aerogel. The thermal and transport behavior of the samples was evaluated, and results were statistically analyzed. Presence of aerogel particles were confirmed through microscopic examination. Thermal behavior was investigated by using thermogravimetric analysis and differential scanning calorimetry. The results showed that the polyvinylidene fluoride nanofibrous membranes embedded with aerogel obtained a good thermal stability with lower weight loss than polyurethane nanofibrous membranes. The glass transition and melting point was not affected by the aerogel content in the layers, validating that polymers are not miscible. The increase in duration of electrospinning led to higher web thickness, which resulted in considerable decrease in air permeability. Considerable improvement of thermal insulation was observed by increasing the number and the weight per unit area of both nanofibrous membranes. The results confirmed increase in thermal insulation by embedding silica aerogel in nanofibrous membranes. With reference to the results, it could be concluded that nanofibers embedded with aerogel are good for thermal insulation in cold weather conditions. Thermal insulation battings incorporating nanofibers could possibly decrease the weight and bulk of current thermal protective clothing. [ABSTRACT FROM AUTHOR]

CuO nanoparticle (NP)-functionalized cellulose-based aerogel (CuO/CBA) with three-dimensional (3D) macroporous structure and abundant active sites was successfully prepared for visible-light photocatalysis via in situ deposition of CuO NPs on cellulose-based aerogel (CBA). Octahedral CuO NPs were formed and anchored onto the surface and inner wall of the cellulose matrix, which acted as a microreactor to prevent aggregation and protect the catalytic character of the CuO NPs. The photocatalytic performance of the CuO/CBA composite catalysts was evaluated using degradation of methylene blue (MB) as model pollutant. The effects of catalyst dosage, initial MB concentration, and solution pH on MB photodegradation were investigated. Use of 3D macroporous CBA improved the MB adsorption capacity and extended the absorption of visible-light irradiation. In particular, in situ deposition of CuO in the cellulose matrix enhanced separation of photogenerated electrons and holes via surface-adsorbed molecular oxygen, and consequently the catalytic activity. The photodegradation rate of MB by CuO/CBA composite catalyst reached 95.79%, much higher than the value of 73.59% for pure CuO. The photodegradation process on the CuO/CBA composite catalysts followed an apparent pseudo-first-order kinetic model. The CuO/CBA composite catalyst was easily recycled and reused, with 80% MB degradation rate retained even after six cycles of irradiation for 30 min each. Such CuO/CBA composite catalysts can be applied for wastewater treatment utilizing solar radiation. [ABSTRACT FROM AUTHOR]

This work is the first attempt to prepare microporous polytetrafluoroethylene (PTFE) fibrous layers embedded with aerogels/phase change materials. For preparation of this layer, the needle-less electrospray technology of water dispersion of individual components is used. Microstructure characteristics, including surface morphology and particle size distribution, and various properties of the prepared materials were investigated and explained. Transport performance of the fibrous layers embedded with aerogels/phase change materials, such as the transmission of heat, air, and water vapor was evaluated and discussed in details. It was found that the electro-sprayed materials composed by spherical particles with rough surface had compact disordered stacking structure. Aerogels and phase change materials (PCMs) play different roles in determining structural parameters and transport properties of the materials. Those parameters and properties could be flexibly adjusted by optimizing the spinning parameters, changing the content or proportion of the fillers to meet specific requirements. [ABSTRACT FROM AUTHOR]

Green and sustainable cellulose aerogels have attracted extensive attention, but are severely limited by unsatisfied elasticity, fatigue resistance as well as fire hazard for functional applications. Herein, we proposed a novel and feasible strategy to fabricate highly elastic, thermal insulating and fireproof phytic acid/cellulose (PA/CE) aerogel via constructing microfilament substructure derived from PA-induced aggregation and assembly of cellulose chains. Benefiting from the interconnected fibrous cellular walls integrating with abundant microfilaments, the resultant PA/CE aerogels demonstrated excellent compressibility and resilience with recovery rate of 91.26% after 100 compressive cycles at 50% strain. With the hierarchical porous structure, PA/CE aerogels exhibited low thermal conductivity of 0.0340–0.0352 W/m·K, could maintain its structural integrity and high temperature thermal insulation after heat treatment for 30 min at 400 ℃. Moreover, the integration of PA enabled aerogel high fireproofing with limiting oxygen index (LOI) of 42.6% and UL-94 V-0 rating. The peak of heat release rate (PHRR) and total heat release (THR) of PA/CE aerogels were 79.97 kW/m2 and 1.75 MJ/m2, reduction by 43.0% and 46.5% compared with cellulose aerogels. Thus, the elastic cellulose aerogels proposed by this strategy provide an insight and feasibility for high performance and multifunctional applications. [Display omitted] • PA-induced aggregation and assembly of cellulose chains was proposed. • The resulting PA/CE aerogels had hierarchical porous structure with plentiful microfilament substructures. • The aerogels displayed excellent compressibility and fatigue resistance with recovery rate of 91.26% after 100 compressive cycles. • The aerogels possessed high temperature thermal insulation with structural integrity bearing heat treatment at 400 ℃ for 30 min. • The aerogels showed high fireproofing with 43.0% and 46.5% reduction of PHRR and THR compared with CE aerogels. [ABSTRACT FROM AUTHOR]

Highlights • A facile method of loading metal-organic frameworks (MOFs) onto cellulose aerogels (CA) is developed. • The equilibrium adsorption capacity of Pb2+ adsorbed by UiO-66-NH 2 @CA was 89.40 mg g−1. • The complete decomposition temperature of UiO-66-NH 2 @CA was increased by 62.1 ℃ compared with CA. • The hybrid aerogels could be recycled without secondary pollution. Abstract In the present work, we develop novel method of loading metal-organic frameworks (UiO-66 and UiO-66-NH 2) on the flexible cellulose aerogels as metal-organic frameworks@cellulose aerogels composite materials by using in situ growth procedure at room temperature. The as prepared metal-organic frameworks@cellulose aerogels composite materials were well characterized via SEM, XRD, atomic absorption spectrometer, and TG analysis, besides the adsorption of Pb2+ and Cu2+ in metal-organic frameworks@cellulose aerogels composite materials was investigated. The amount of metal ions adsorbed by metal-organic frameworks@cellulose aerogels composite materials is equal to the sum of metal-organic frameworks and cellulose aerogels, indicating that the metal-organic frameworks are not blocked after cellulose aerogels growth and still have adsorption properties. It was found that metal-organic frameworks@cellulose aerogels composite materials can be recycled to adsorb Pb2+ and Cu2+ in water after simple cleaning. The equilibrium adsorption capacity of Pb2+ adsorbed by UiO-66-NH 2 @CA was 89.40 mg g−1, and can be easily reused for more than 5 cycles without significant decrease in performance. Moreover, the maximum decomposition temperature (T max) of UiO-66-NH 2 @CA was increased by 62.1℃. This result suggested that such metal-organic frameworks@cellulose aerogels composite materials could adsorb heavy metal ions in water could by avoiding secondary pollution and show great potential in water treatment. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) as catalysts for the activation of peroxymonosulfate (PMS) to remove recalcitrant organic contaminants has been well reported, however, the separation of MOFs from the solution is difficult because of their powder state, which limits their applications. In the present study, zeolitic imidazole framework (ZIF) materials, ZIF-9 and ZIF-12 were pioneered to load on cellulose aerogels, and the hybrid aerogels as metal catalysts to effectively activate PMS for Rhodamine B (RB), tetracycline hydrochloride (TC) and p-nitrophenol (PNP) degradation. The hybrid aerogels/PMS system could remove PNP about 90% in 1 h, which hard to remove from water. The pH value of the solution had no effect on the degradation process, which demonstrated that the hybrid aerogels had excellent pH tolerance. In addition, the mechanism of PNP degradation was investigated by electron paramagnetic resonance (EPR) and free radical trapping methods. The results showed that PMS could effectively activate by hybrid aerogels to produce sulfate radicals (SO 4 −), hydroxyl radicals ( OH), and revealed that SO 4 − play a key role in degradation. The most important feature of hybrid aerogels is can be easily separated from the solution. The obtained results showed that the hybrid aerogels exhibit excellent recyclability, with no significant effect on degradation. The prepared hybrid aerogels are green, environmentally friendly with high catalytic efficiency. Further, the outstanding degradation of PNP demonstrates the promising prospects of hybrid aerogels as advanced oxidation process (AOP) catalysts. [ABSTRACT FROM AUTHOR]

Nanostructured materials with designable microstructure fabricated through a facile and green method are highly desired for practical applications in nanotechnology. Herein, without using any toxic reagents, flexible cellulose aerogel nanocomposites embedded with ZnO@noble metal nanoparticles (NPs) were successfully prepared from a cellulose dope. Morphology, structure, and mechanical properties of the nanocomposite were characterized. Flower-liker ZnO particles were synthesized through cellulose mineralization and it acted as a platform for efficient photocatalytic synthesis of noble metal (Ag, Au, Ag-Au) NPs. The noble metal NPs were well dispersed in the three-dimensional (3D) cellulose skeleton, resulting in abundant "hot spots" for high Surface Enhanced Raman Scattering (SERS) signal enhancement. Using rhodamine 6 G (R6G) molecules as probe molecules, the detection limits and calculated enhancement factors approached to 10−10 M and 4.8 × 107, respectively. Particularly, the photocatalytic capabilities of noble metal-semiconductor heterostructure embedded in porous aerogel made it a self-cleaned SERS substrate. There was little sensitivity loss after recycling use for 3 times. This work presented a sustainable and cost-reduction strategy to construct sensitive SERS substrate. [Display omitted] • Cellulose aerogel embedded with ZnO@Ag/Au is facilely fabricated from a dope. • The actived celluloe chains act as mineralization template for flower-like ZnO. • Ag/Au NPs are plated to ZnO surface through a controllable photoreduction method. • 3D porous aerogel gives anchoring effect for particles and bring abundant "hot spots". • Hierarchical nanostructures achieves a flexible, sensitive and reusable SERS strips. [ABSTRACT FROM AUTHOR]

The low cost of adsorption treatment of heavy metal ions in water has been extensively studied. In this paper, we have demonstrated a facile method of combining two emerging materials cellulose aerogels (CA) and metal–organic frameworks (MOFs) into one highly functional aerogel to adsorption removal of heavy metal ions from water, by entrapping MOF particles into a flexible and porous CA. The resultant hybrid cellulose aerogels had a highly porous structure with zeolitic imidazolate framework-8 (ZIF-8) loadings can reach 30 wt%. The hybrid cellulose aerogels (named as ZIF-8@CA ) show good adsorption capacity for Cr(Ⅵ). The adsorption process of ZIF-8@CA is better described by pseudo-second-order kinetic model and Langmuir isotherm, with maximum monolayer adsorption capacity of 41.8 mg g −1 for Cr(Ⅵ), whose adsorption capacity has greatly improved when compared with a single CA or ZIF-8. Thus, such a flexible and durable hybrid cellulose aerogel is a very prospective material for metal ions cleanup and industrial wastewater purification. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) and their derived powder catalysts are prone to agglomerate and difficult to recycle in water, thus resulting in their low utilization and secondary pollution in water treatment. Herein, a composite aerogel (CoFe0.8@NCNT@CA) loaded with bimetallic MOF-derived carbon nanotubes on cellulose aerogel was developed for activating peroxymonosulfate (PMS) to degrade tetracycline (TC). The CoFe0.8@NCNT@CA/PMS system exhibits an excellent TC removal rate (97.1 % TC removal within 20 min). The outstanding performance of the composite catalyst is closely related to the synergistic effect of bimetallic catalytic sites, graphitic N structure, and porous network. Interestingly, carbon nanotubes and cellulose in the composite catalyst form a semi-coated porous structure, which can effectively enhance the adhesion of carbon nanotubes and expose abundant active sites while ensuring mass transfer. This study provides a strategy for synthesizing novel composite aerogel with an excellent structure and physicochemical properties for water treatment. MOF-derived carbon nanotubes form a semi-encapsulated structure with the cellulose aerogel, catalytic metal sites are wrapped in carbon nanotubes. Tetracycline is degraded with CoFe0.8@NCNT@CA process through superoxide radical mechanism, hydroxyl radicals and sulfate radical co-oxidation mechanisms. [Display omitted] [ABSTRACT FROM AUTHOR]

It is of great significance to capture radioiodine from nuclear-related activities. Herein, We fabricated two kinds of hybrid aerogels composed with bimetal Hofmann-type metal-organic frameworks (Co–Fe)II(pz)[NiII(CN) 4 ] and cellulose aerogels by in-situ growth and doping method (named CoFe@CA-IS and CoFe@CA-D, respectively). The hybrid aerogels possessed excellent iodine adsorption performance. The addition of (Co–Fe)II(pz)[NiII(CN) 4 ] increased the porosity of the hybrid aerogels. The porosities of CoFe@CA-IS and CoFe@CA-D were reached 86.7% and 87.8%, respectively, which are higher than pure cellulose aerogels. Furthermore, the doping method provide a significant improve of adsorption performance. The equilibrium adsorption capacity of CoFe@CA-D reached 457.99 mg g−1 and the equilibrium adsorption capacity of CoFe@CA-IS was 194.34 mg g−1. In addition, the hybrid aerogels showed excellent recycle ability, the equilibrium adsorption capacity of CoFe@CA-IS and CoFe@CA-D remained 81% and 91% after 5 cycles. The results suggested that this metal-organic framework@cellulose hybrid aerogel showed great potential in iodine treatment and could be applied in a wide field. A metal-organic framework@cellulose aerogel was synthesized and exhibited outstanding adsorption performance for iodine. Image 1 • Bimetal Hofmann-type MOFs are developed and (Co–Fe)II(pz)[NiII(CN) 4 ] shows the excellent iodine adsorption performance. • Two type of hybrid aerogels are successfully fabricated by in-situ growth and doping method. • CoFe@CA-D shows excellent iodine adsorption performance and the equilibrium adsorption capacity remained 91% after 5 cycles. [ABSTRACT FROM AUTHOR]

The recently-developed MOFs-based hydrogels and aerogels can overcome the disadvantages of powdered MOFs such as fragile, unstable, unprocessable and unrecoverable, which has become a hot topic now. Here, we summarize the recent progress in the preparation of MOFs-based hydrogels and aerogels as well as their applications in drug control release, wound healing, sensing, energy storage, catalysis, water treatment, and gas adsorption applications. • This paper reviewed the recent progress in metal-organic frameworks-based hydrogels and aerogels. • The categories of metal-organic frameworks-based hydrogels and aerogels were divided in detail. • Key application fields of metal-organic frameworks-based hydrogels and aerogels were discussed. • Future outlook for metal-organic frameworks-based hydrogels and aerogels. In recent years, metal-organic frameworks (MOFs) have attracted incredible chemical and material research interests because of their prominent properties and charming structures. The reliable production of a wide variety of MOFs materials and MOF derivatives, such as MOF-metal nanoparticles composites and MOFs-polymers hybrids, offers many possibilities to develop MOF-based applied materials. Although MOFs have many unique features, including abundant pore structures and multiple functional ligands, their applied performance is limited by intrinsic fragility and powdered crystalline state, as well as unsatisfied stability and processability. By this, MOF-based hydrogels and aerogels have achieved unparalleled results, outperforming ungelated MOFs materials in many aspects. This review presents current developments of MOF-based hydrogels and aerogels with emphasis on the specific categories and the synergistic effects of MOF-derived aerogels between MOFs and additional materials. Particular emphasis is placed on discussing the advantages of MOF-based hydrogels and aerogels in applications such as sensors, batteries, supercapacitors, adsorbents, catalysts etc. MOF-based hydrogels and aerogels can provide valuable guidance for the investigation of MOFs towards practical applications with processability, stability, and easy handling. Specifically, we will summary recent progress of pure MOF hydrogels, MOF@biology derived organic macromolecules hydrogels, MOF@biocompatible hydrogels, MOF@ graphene hydrogels, pure MOF aerogels, MOF@silica aerogel composites, MOF@ graphene aerogel composites, MOF@cellulose aerogel composites, and aerogel composites containing MOFs-derived materials. In addition, their applications are also discussed. We hope that this review will be helpful for those who want quick access to valuable references about MOF-based hydrogels and aerogels and their applications. [ABSTRACT FROM AUTHOR]