作者机构：
[邓凌峰; Qin, Yu-Kun; 彭辉艳; 连晓辉; 吴义强] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha;410004, China;[邓凌峰; Qin, Yu-Kun; 彭辉艳; 连晓辉; 吴义强] 410004, China
通讯机构：
[Deng, L.-F.] S;School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China
摘要：
Cellulose nanofibrils (CNFs), disintegrated from natural fibers, are promising alternatives in wastewater purification for the porous structure and numerous hydroxyls. The pristine CNFs aerogel has limited mechanical strength and are vulnerable to collapse when exposed to water. In this work, eco-friendly and recycled CNFs aerogel adsorbents were successfully prepared using cellulose nanofibrils (CNFs), which cross-linked by poly(vinyl alcohol) (PVA) and acrylic acid (AA). The combination of PVA and AA endowed CNFs aerogel strong three-dimensional porous structure and desirable adsorption properties. The heavy metal ions were adsorbed on the CNFs-PVA-AA (CPA) adsorbents efficiently and the maximum adsorption capacities for Cu2+ and Pb2+ approached 30.0 mg/g and 131.5 mg/g, respectively. The CPA adsorbent also showed excellent reusability and their adsorption capacities maintained 89% and 88% for Cu2+ and Pb2+ after 5 repeated uses. The adsorption of these heavy metal ions were confirmed to follow pseudo-second-order kinetic and Langmuir isotherm model. The functions of C = O and -OH were the major adsorption sites. Chemical adsorption combined with the porous physical adsorption made the CPA to be excellent adsorbent for the removal of heavy metal ions in wastewater.
摘要：
Although hydrogel electrolytes have attracted considerable attentions due to high water retention and low leakage, their vulnerability and low conductivity still pose challenges in large-scale applications. In this work, a mechanically strong and highly conductive poly (acrylic acid) (PAA) electrolyte reinforced by cellulose nanofibrils (CNFs) is developed via versatile blending followed by polymerization. As a result of physical entanglement and hydrogen bonding, the mechanical strength of the PAA electrolyte is enhanced from 0.656 to 1.875 MPa at a CNF loading of 3 wt%, and the dimensional swelling is suppressed to half of its original level. The ionic conductivity of the composite electrolyte is improved by 100% due to excellent ion-transfer paths created by the hydroxyl groups exposed on the surfaces of CNFs. Furthermore, the CNF/PAAs exhibit preferable elasticity and flexibility with the maximum elongation at break reaching greater than 600%. These electrolytes are able to maintain the initial ionic conductivity even after being stretched to 100% elongation for 500 circles. After assembling with an air cathode and an aluminum anode, the as-prepared Al-air battery show good discharging performance, demonstrating promises for applications in portable and flexible electronic devices. (c) 2018 Elsevier Ltd. All rights reserved.
作者：
Caichao Wan;Yue Jiao;Daxin Liang;Yiqiang Wu;Jian Li
期刊：
Advanced Energy Materials,2018年8(33):1870145- ISSN：1614-6832
作者机构：
[Yue Jiao; Daxin Liang; Jian Li] Material Science and Engineering College, Northeast Forestry University, Harbin, 150040 P. R. China;[Caichao Wan; Yiqiang Wu] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004 P. R. China
摘要：
Urea-formaldehyde (UF) resin is one of the most widely used adhesives in wood-based composites. The major concerns of the resin utilization are free formaldehyde release and poor water resistance. In this study, based on life cycle assessment (LCA) analysis, a “greener” adhesive composed of UF resin and cottonseed meal was successfully prepared via a common synthetic process of pure UF resins. The raw materials (urea and formaldehyde) of UF resins were replaced by cottonseed meal with up to 40% on weight basis. The effect of the cottonseed meal on the rheological property, mechanical strength, chemical structure, thermal stability, and glue line features of these “greener” adhesives was investigated. The adhesive showed an improved mechanical strength as compared to pure UF resins in the tensile shear strength of bonded wood specimens, especially on the water soaked strength. It also showed similar chemical structures, thermal stabilities, and even better rheological properties than pure UF resins. Cottonseed meal resulted in good dispersions in these adhesives with up to 30% portion. It acted as a reinforcement for the adhesive other than a filler or an additive. This “greener” adhesive improved the performance of pure UF resins while retained its outstanding features, suggesting the feasibility of using it as UF resins in current manufacturing lines for wood-based composites is there.
作者机构：
[Wu, Yiqiang; Wang, Lijun; Tian, Cuihua; Yan, Ning; Huang, Yuanxin; Qing, Yan] Cent South Univ Forestry & Technol, Coll Mat Sci & Technol, Changsha, Hunan, Peoples R China.;[Wu, Yiqiang; Qing, Yan] Cent South Univ Forestry & Technol, Hunan Prov Collaborat Innovat Ctr High Efficiency, Changsha, Hunan, Peoples R China.;[Yan, Ning] Univ Toronto, Fac Forestry, Toronto, ON, Canada.
通讯机构：
[Qing, Yan] C;Cent South Univ Forestry & Technol, Coll Mat Sci & Technol, Changsha, Hunan, Peoples R China.;Cent South Univ Forestry & Technol, Hunan Prov Collaborat Innovat Ctr High Efficiency, Changsha, Hunan, Peoples R China.
摘要：
An environment-friendly fluorescent nano-hybrid hydrogel has been synthesized successfully, from cellulose nanocrystal (CNC), acrylic acid (AA) and phosphorescent Eu(2+)/Dy(3+) doped SrAl2O4 via free radical polymerization. The hydrogel network matrix fixed Eu(2+)/Dy(3+) doped SrAl2O4 nanoparticles by polymer chains with coordinate bonds that prevented particles from aggregating and quenching in water. The fluorescent nano-hybrid hydrogel exhibited extremely high water absorption of which the swelling ratio in distilled water and NaCl salt solution were respectively of 323.35 g/g and 32.65 g/g. Furthermore, the hydrogel displayed excellent water retention property that can keep half of the moisture even exposed to 80 degrees C for 210 min. Besides, the hydrogel had bright green fluorescence under the sunlight or ultraviolet excitation, and the fluorescence intensity was up to 125477 after swelling 50 times in water. The time-resolved photoluminescence (TRPL) afterglow decay examination showed that the fluorescent emission persisted for 4 h after hydrogels excited at 368 nm wavelength UV-light for 10 min. The fluorescence intensity behaved significant linear relationship with the swelling ratio. As a result, these hydrogels were considered as promising candidates for the preparation of stable and sensitive sensor materials in green water detection.
摘要：
Cellulose nanofibers (CNFs) were prepared through acid hydrolysis and used in combination with graphene nano-platelets (GNPs) as modifiers for oil well cement (OWC). The rheology behavior of CNF/GNP-OWC slurries at three temperatures (i.e., 20, 40, and 60 degrees C) was measured and modeled using four different rheological models. Thermal properties, surface functional groups, morphology, and mechanical performance of the composites were characterized. CNF/GNP-OWC slurry exhibited a typical shear-thinning behavior with reduced shear viscosity at higher shear rates. The use of CNFs and GNPs led to increased yield stresses of fresh CNF/GNP-OWC slurry and temperature significantly influenced the yield stress values. Among these rheology models, the Vom Berg model exhibits the best fitting result of the slurry rheology data (R-2 = 0.999). The addition of CNFs and GNPs increased degree of hydration (DOH) value of CNF/GNP-OWC composites. Both flexural and compressive strengths of the CNF/GNP-OWC composites were enhanced with added CNFs and GNPs. The reinforcing mechanism was attributed to the increased DOH, reduced pores, and bridging effect of CNFs and GNPs in the composites. (C) 2016 Elsevier Ltd. All rights reserved.
摘要：
Engineering porous heteroatom-doped carbon nanomaterials with remarkable capacitive performance is highly attractive. Herein, a simple and smart method has been developed to synthesize phosphorus (P) doped carbon with hierarchical porous structure derived from lignocellulose. Hierarchically porous P doped carbon is readily obtained by the pyrolysis of lignocellulose immersed in ZnC1(2)/NaH2PO4 aqueous solution, and exhibits excellent capacitive properties. The as-obtained P doped porous carbon delivers a significant capacitance of 133 F g(-1) (146 mF cm(-2)) at a high current density of 10 A g(-1) with outstanding rate performance. Furthermore, the P doped carbon electrode yields a long-term cycling durability with more than 97.9% capacitance retention after 10000 cycles as well. A symmetric supercapacitor with a maximum energy density of 4.7 Wh kg(-1) is also demonstrated based on these P doped carbon electrodes. (C) 2017 Elsevier B.V. All rights reserved.
摘要：
In situ micro-Fourier transform infrared (FTIR) spectra of a typical cellulose nanofiber (CNF) film (i.e., CNF with cellulose I structure) were collected within the full relative humidity (RH) range from 0% to 90%. Red shifts of two peaks at 1036 and 1204cm(-1) and the variation of different spectra indicated the chemical adsorption sites for adsorbed water. From component band analysis of the spectral range of 2900-3700cm(-1), three component peaks at 3293, 3397, and 3543cm(-1) were due to strongly, moderately, and weakly hydrogen-bonded water. The signatures of these three types of hydrogen-bonded water were then observed to rise with an increase in RH. Based on growth regularities of these three types of hydrogen-bonded water, the water adsorption process of CNF film was divided into three stages; most of the water absorbed in these three stages was demonstrated to be CNFHOHCNF, WATERHOHWATER, and five-molecule tetrahedral structure, respectively.
作者机构：
[胡云楚; 冯斯宇; 田梁才; 黄自知] College of Science, Central South University of Forestry and Technology, Changsha, 410004, China;[吴义强; 袁利萍] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China
