BIOMACROMOLECULES
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2020
·
IF 6.092
Yanlei Hu,Liang Liu,Juan Yu,Zhiguo Wang,Yimin Fan
Native biopolymer nanofibers (cellulose, chitin, and silk nanofiber) are one of the most important contributors to the outstanding functions and mechanical properties of natural materials. To enhance the mechanical performance, A great deal of top-down routes have been reported to prepare biopolymers nanofibers/nanowhiskers that retaining their nanostructures. Compared with advances in cellulose and chitin nanofibers/nanowhiskers, it remains difficult for direct downsizing the natural silk fibers into silk nanofibers/nanowhiskers (SNFs/SNWs) because of their high crystallinity and sophisticated structures. In this work, environmentally friendly and recyclable deep eutectic solvents (DESs) were used to direct pretreat and downsize natural silks into silk nanowhiskers with high yield. SNWs with similar diameter (3.1–22 nm for OA/ChCl DES treated SNWs, 2.7–20 nm for CA/ChCl DES treated SNWs) and contour length (329 ± 140 nm for OA/ChCl DES treated SNWs, 365 ± 200 nm for CA/ChCl DES treated SNWs) to individual nanofibers in natural silk fibers were obtained. In addition, the separated DES with a recovery yield of at least 92% could be reused four times to produce SNWs, indicating the possibility of DESs as green solvents for sustainable biopolymer nanomaterial extraction. Based on the inherent amphoteric properties of SNWs, multicompatibility was explored to facilely composite SNWs with various polymers for preparation of coextruded membranes with enhanced performance and endowed the composites with protein-endowed double adsorption properties. Overall, this work demonstrated that the DES pretreatment process is promising for green and low-cost biopolymer nanomaterial extraction and that the SNWs prepared via DES have good prospects as nanoscale materials in the environmental field and in development of smart biomaterials and drug delivery in biomedicine.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Zhuang Wang,Asad Mahmood,Xiaofeng Xie,Xiao Wang,Hanxun Qiu,Jing Sun
For the oxide-based photocatalysts, polyoxylic acid modification can affect their adsorption/desorption properties and further regulate photocatalytic reaction pathway, which is crucial for enhancing photocatalytic activity and selectivity. Herein, phosphoric acid modified TiO 2 was synthesized by a facile impregnation-calcination method for photocatalytic degradation of gaseous o-xylene. According to FTIR, XPS, and EDS analysis, phosphoric acid was anchored on the surface of TiO 2 successfully. The surface P atomic percentages for PT1 was 2.45%. The as-prepared phosphoric acid modified TiO 2 (PTx) had a photocatalytic performance superior to that of commercial TiO 2 and unmodified TiO 2 (PT0), with increasing by 2.2 times at most. Interestingly, the phosphoric acid molecules strongly adsorbed on anatase TiO 2 surface by forming H–O 2C and =O–Ti 5C chemical bonds according to the first principle calculations, which changed TiO 2 surface properties (specific surface area and surface negative electrostatic field) and further improved adsorption and charge carrier separation and transfer, thus improving the photocatalytic activity. Additionally, according to the intermediates results, the relative abundance of intermediates shows obvious difference. Acetone was detected as the most abundant intermediates during o-xylene degradation for PT0, whereas that was o-methyl benzaldehyde for PT1, which could be ascribed to the difference of surface adsorption configuration of o-xylene. According to the temperature-programmed desorption (TPD) results, the surface modified by phosphoric acid could change the o-xylene adsorption configuration to favor its methyl oxidation (standing configuration), whereas the unmodified surface could be more favorable to the benzene ring-open reaction (lying configuration). This work will deepen the understanding of the relevance of surface modification and surface photocatalytic reaction, which also provides a feasible strategy to improve photocatalytic selectivity.
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CERAMICS INTERNATIONAL
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2020
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IF 3.83
Qian Dai,Bingnan Yuan,Minghui Guo,Kun Zhang,Xueqi Chen,Zihui Song,Tat Thang Nguyen,Xiaojing Wang,Shudong Lin,Jincheng Fan,Yingchun Li,Hu Liu,Zhanhu Guo
To improve the photocatalytic efficiency of niobium pentoxide (Nb 2 O 5 ) for the degradation of organic pollutants, a novel nano-fibriform C-modified Nb 2 O 5 (F–C/Nb 2 O 5 ) photocatalyst was successfully synthesized by niobium oxalate as precursor and nanofibrillated cellulose (NFC) as template and carbon source. Vacuum induced self-assembly method was used to form the nano-fibriform morphology. Compared to ordinary C/Nb 2 O 5 and commercial Nb 2 O 5 , F–C/Nb 2 O 5 exhibited a typical three-dimensional nanorod structure with plenty of pores. The specific surface area of F–C/Nb 2 O 5 was 3 times that of C/Nb 2 O 5 . The prepared F–C/Nb 2 O 5 exhibited a 3.01 eV bandgap and was able to be activated under visible light while that was unable for commercial Nb 2 O 5 with 3.19 eV bandgap. The F–C/Nb 2 O 5 showed the best photocatalytic efficiency in pH value ≤ 3. After cycling for 5 times, the photocatalytic efficiency of F–C/Nb 2 O 5 was still 2.4 times of the ordinary C/Nb 2 O 5 under visible light. Meanwhile, the self-assembly mechanism and photodegradation mechanism were proposed. This study provides a new strategy to form a special nano-fibriform C-modified niobium pentoxide with extremely high photocatalytic efficiency in aqueous solutions.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
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IF 5.162
Kaiwei Zhang,Songming Zheng,Yuqing Liu,Jinyou Lin
Cellulose nanofibrils (CNF) is a natural nanomaterial composed of biomacromolecules that can be extracted from plants and has great potential applications in many fields due to its excellent regenerative, sustainable, and biodegradable properties. In this work, the flax CNF with hierarchical scales was obtained by using the flax fibers (FF) treated with different concentrations of alkaline solution, followed by the TEMPO-mediated ternary oxidation and mechanical treatment. Subsequently, the resultant CNF was implanted on the commercial filter paper as a surface barrier for oil/water preparation. The changes of cellulose crystal form and crystallinity caused by alkali treatment on FF were studied by Fourier transform infrared spectroscopy and X-ray diffraction. Morphological changes of FF before and after alkali treatment were observed. The morphology of obtained CNF was examined. Moreover, the transmittance of the prepared CNF suspension and films was also investigated by a UV spectroscopy . The prepared modified filter paper can effectively separate the oil/water mixture, which gives themselves promise as candidates in practical applications of oil/water separation.
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Nanomaterials
·
2020
·Vol. 10
·期 1
·112
·
IF 4.324
Huixiang Wang,Subir Kumar Biswas,Sailing Zhu,Ya Lu,Yiying Yue,Jingquan Han,Xinwu Xu,Qinglin Wu,Huining Xiao
Recently, with the development of personal wearable electronic devices, the demand for portable power is miniaturization and flexibility. Electro-conductive hydrogels (ECHs) are considered to have great application prospects in portable energy-storage devices. However, the synergistic properties of self-healability, viscoelasticity, and ideal electrochemistry are key problems. Herein, a novel ECH was synthesized by combining polyvinyl alcohol-borax (PVA) hydrogel matrix and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-cellulose nanofibers (TOCNFs), carbon nanotubes (CNTs), and polyaniline (PANI). Among them, CNTs provided excellent electrical conductivity; TOCNFs acted as a dispersant to help CNTs form a stable suspension; PANI enhanced electrochemical performance by forming a “core-shell” structural composite. The freeze-standing composite hydrogel with a hierarchical 3D-network structure possessed the compression stress (~152 kPa) and storage modulus (~18.2 kPa). The composite hydrogel also possessed low density (~1.2 g cm−3), high water-content (~95%), excellent flexibility, self-healing capability, electrical conductivity (15.3 S m−1), and specific capacitance of 226.8 F g−1at 0.4 A g−1. The fabricated solid-state all-in-one supercapacitor device remained capacitance retention (~90%) after 10 cutting/healing cycles and capacitance retention (~85%) after 1000 bending cycles. The novel ECH had potential applications in advanced personalized wearable electronic devices.Keywords:cellulose nanofibers;carbon nanotube;polyaniline;hydrogels;supercapacitor
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ENVIRONMENTAL RESEARCH
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2020
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IF 5.715
Cong Li,Hongyang Ma,Shyam Venkateswaran,Benjamin S. Hsiao
Carboxylated cellulose filters were fabricated by oxidation of a cellulose fibrous mat via TEMPO-mediated oxidation. These carboxylated cellulose filters were employed as sustainable filters for removal and recovery of lanthanum ions (La (III)) with high adsorption capability. The surface chemistry of the carboxylated cellulose fibers before and after adsorption of La (III) was investigated systematically. The distribution of La (III) on carboxylated cellulose fibers were explored by EDX mapping approach, which revealed that the adsorption occurred on both the surface and the internal structure of the cellulose fibers. The kinetics and isotherms of the adsorption were conducted to understand the adsorption mechanism of the carboxylated cellulose filter and to learn the maximum adsorption capacity for La (III) which was as high as 33.7 mg/g. The adsorption selectivity of the carboxylated cellulose filter for La (III) was determined when interfering ions including mono- and di-covalent ions were involved. The carboxylated cellulose filter exhibited high adsorption capability and high permeation flux evidenced by the breakthrough curves of the dynamic adsorption of La (III) under an extremely low pressure of 0.07 kPa. A variety of desorption reagents were selected to recover lanthanum from the carboxylated cellulose filter, where the optimized conditions for recovery were explored. Finally, a spiral wound cartridge of the carboxylated cellulose fibrous mat was fabricated and the removal and the recovery of La (III, 2.5 ppm) from massive lanthanum-containing water were demonstrated. It was very impressive that the high rejection ratio of 94.3% was achieved under the low pressure drop of 3.0 kPa remaining throughout the separation process, and the treated solution volume was high up to 21.4 L, which was about six-times higher than that of commercially available nanofibrous adsorption membranes, indicating that the carboxylated cellulose filter could be used as a highly efficient adsorption medium for industrial recovery of rare earth metals .
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高影响因子
CELLULOSE
·
2020
·Vol. 27
·期 11
·6217-6233
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IF 4.21
Jiang Shuai,Zhang Meiling,Li Mengmeng,Liu Liu,Liu Lifang,Yu Jianyong
Abstract Herein, a facile method on fabricating aerogels with hierarchical porous structures was created by freeze-drying the cellulose nanofibril (CNF)/methyltrimethoxysilan (MTMS)/fumed silica (FS) suspension. FS was introduced for its porous structure, which could improve the thermal insulation performance of freeze-dried aerogels. The as-prepared aerogels were hydrophobic with improved mechanical properties (elastic recovery rate was up to 99.7%) and reduced thermal conductivity (0.027 Wm −1 K −1 at 25 °C). Most importantly, the addition of FS was proved to improve the thermal insulation stability of cellulose aerogels efficiently in different values of relative humidity (RH) and temperatures. The thermal conductivity of pure CNF aerogel conditioned at 25 °C and 95% RH was 196% higher than that of the fully-dried one, while the increase was 56% for the composite aerogel. Besides, at 30% RH, the thermal conductivity increased by 24% for the pure CNF aerogel when tested from 20 to 60 °C while only a 2% increase for the composite aerogel. Moreover, when tert-butanol was used as the solvent to optimize the distribution of the pores of freeze-dried aerogels, their thermal insulation performance was further improved. Our work provides easily available CNF/MTMS/FS ternary aerogels, which are stable in thermal conductivity in the changing environment. Graphic abstract
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SENSORS AND ACTUATORS B-CHEMICAL
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2020
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IF 7.1
Junjun Fu,Jiayi Zhu,Yan Tian,Kui He,Huang Yu,Linlin Chen,Dongjun Fang,Dongmei Jia,Jinyi Xie,Hao Liu,Jiasheng Wang,Fangcheng Tang,Jinsong Tao,Jinbin Liu
Mercury(II) pollution is a growing threat to the environment and humanity. But most of the solution-based Au nanomaterial sensors suffer from low stability seriously. Here, inspired by high-affinity metallophilic Hg 2+ –Au(I) interaction mechanism, we introduced a transparent cellulose nanofiber matrix-supported luminescent gold nanoparticle (AuNPs) stable sensing membrane. In this solid-state membrane, the AuNPs with strong red fluorescence emission were synthesized as the sensor unit. Cellulose nanofibrilatted (CNF) matrix was fabricated as the supporting substrate. With a large specific surface area, the nanostructured CNF matrix offers abundant immobilizing spots to the sensor unit of AuNPs. More importantly, the excited fluorescence can escape directly without apparent scattering loss due to the high transparency of the CNF substrate. With strong emission of the AuNPs, coupled with abundant AuNP immobilizing spots and high transparency of the CNF substrate, the fluorescence signaling path was manipulated sequentially from signal generation, transmission until to quenching, resulting in the membrane demonstrates high sensitivity, selectivity, and stability. The detection limit of 1.0 nM is markedly lower than the threshold level of 10.0 nM permitted by US EPA. Aided with the high-performance membrane, the detection of Hg(II) becomes simple, fast, easy handing, and green. We envision the membrane will be an attractive material for Hg(II) monitor.
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高影响因子
CARBOHYDRATE POLYMERS
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2020
·
IF 7.182
Ya Liu,Yipeng Zhang,Tougen Liao,Li Gao,Meng Wang,Xu Xu,Xinxin Yang,He Liu
Boron nitride nanosheets (BNNSs) are desirable materials for thermal management applications owing to their excellent thermal conductivity. Such property also related to the increased thermal transfer efficiency per unit mass, which can be improved by constructing three-dimensional (3D) structures. Cellulose nanofibers (CNFs) are often used to prepare 3D skeletons and stabilize the dispersion of inorganic fillers. Therefore, CNF/BNNS aerogels were prepared to disperse BNNS in a 3D network. CNF/BNNS aerogel exhibited a thermal conductivity of 0.57 W m −1 K −1 , which is an enhancement of 443 % compared to 0.105 W m −1 K −1 of CNF aerogel. The surface temperature changes of the aerogels were confirmed a strong thermal management capacity. The BNNSs also resulted in the compressive strength increased from 0.25 MPa (CNF aerogel) to 0.37 MPa (CNF/BNNS aerogel). This study provides an effective strategy for the preparation of cellulose-based nanocomposite aerogels with excellent thermal management properties and mechanical properties.
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2020
·Vol. 38
·期 10
·1061-1071
·
IF 3.154
Liu Si-Yuan,Gong Yan-Bin,Ma Shan,Wang Yu-Huan,Gan Lin,Huang Jin
Static charges on optical anti-counterfeiting membranes may lead to materials structural changes, dust stain aggravation, and misreading of optical information. Incorporating conductive particles is a common way to transfer accumulative charges, but the key issue is how to achieve high dispersion and effective distribution of particles. According to the strategy of assembly-induced structural colors, cellulose nanocrystals (CNCs) were employed as a solid emulsifier to stabilize hydrophobic carbon nanoparticles (CNPs) in aqueous media; subsequently, by solvent-evaporation-modulated co-assembly under a condition of 30 °C and 20 RH%, the binary suspensions containing 2 wt% CNC and CNPs with the equivalent concentration relative to CNC ranged from 1:40 to 1:10 were used to prepare antistatic composite membranes. Surface chemistry regulation of CNCs was applied to optimize the dispersibility of CNPs and the orientation of assembled CNC arrays, and the hydrophilic CNCs were more favorable for dispersion and assembly of binary suspension systems. Meanwhile, one-dimension carbon nanotube (CNT) and zero-dimension carbon black (CB) were found to show better dispersibility than two-dimension graphene, which was verified by a semiquantitative theoretical study. Moreover, the stable binary systems of CNT/CNC and CB/CNC were chosen for co-assembly as membranes, and the uniaxial orientation could be optimized as the full-width of 9.8° at half-maximum deviation angle while the surface resistivity could also drop down to 3.42 × 10 2 Ω·cm·cm −1 . The structural color character of such paper-homology and antistatic-integrated membranes contributes to optical information hiding-and-reading, and shows great potential as optical mark recognition materials for electrostatic discharge protective packaging and anti-counterfeiting applications.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 33
·14180-14188
·
IF 3.288
Jingjing Zhang,Jingtao Dai,Jian Chen
To compare photodegradation processes in single- and binary-contaminant systems, a representative antibiotic (tetracycline) and insecticide (imidacloprid) were employed as two contaminants of emerging concern. Ag/AgBr modified BiOBr was synthesized hydrothermally in an ionic-liquid/water medium and characterized via various techniques to support mechanistic studies. As-prepared flower-shaped Ag/AgBr/BiOBr exhibits superior photocatalytic activity to Ag/AgBr and BiOBr. Parallel experiments were conducted in single-contaminant systems to optimize the solution chemistry for comparison studies; these suggested that the photodegradation rate (DR) is highest at 1.0 g L−1 at catalyst dosages ranging from 0.6 to 1.4 g L−1, while raising the initial concentration reduces the DR. Additionally, electrostatic interactions between the reactants and photocatalyst cause DR fluctuations at different pH values. In the mechanistic studies, the contributions of the dominant active species (˙O2− and h+) were analysed quantitatively through quenching tests with scavengers. Furthermore, electrostatic interactions between the reactants and the active species result in non-equilibrated contributions from ˙O2− and h+ in single-contaminant systems. Comparison studies distinctly demonstrated a synergistic effect in binary-contaminant systems, which is caused by the mutually complementary utilization of h+ and ˙O2− during the photodegradation of tetracycline and imidacloprid.
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REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Bin Chu,Chaoxi Wu,Shunqing Tang,Mei Tu
A sprayable wound dressing is convenient, simple and easy to administer by nonmedical personnel in clinical medicine. In this study, agarose was employed for the first time as a spray for wound care. The strong gelling properties and cross-linked network structure of agarose makes it unsuitable for spraying. Furthermore, agarose gel exhibits shrinkage and is resistant to degradation. These features constitute major disadvantages of agarose as a wound dressing. To overcome these problems, we degraded and modified agarose using the 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation method, prepared degraded carboxylated agarose (Ag-CA) to improve the biodegradability , and developed a microgel structure that is easy to spray. In addition, we grafted dopamine onto Ag-CA (to yield Ag-g-DA) and evaluated its adhesion to cells and wounds. The surface topography , cell adhesion, tissue adhesion and protein release capabilities of the materials were evaluated, and a histological analysis was performed at 1, 2, 3, and 4 weeks. The introduction of carboxyl and catechol functional groups enabled agarose to bind to cells and thereby promote cell adhesion and growth. The wound adhesion and repair due to Ag-CA and Ag-g-DA were superior to those of unmodified agarose. Furthermore, the agarose-derived hydrogels promoted the downregulation of proinflammatory cytokines, suggesting a potential direction for research in skin regeneration and repair.
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