查找使用阿拉丁产品的科研文献

Protective coating of paper works: ZnO/cellulose nanocrystal composites and analytical characterization

Minghao Jia,Xiaogang Zhang,Jiajia Weng,Jie Zhang,Meifang Zhang

Coating of ZnO-cellulose composites on paper surface has potential technological applications. With this motivation, a simple approach of synthesizing ZnO nanoparticles in cellulose nanocrystals (CNC) by in-situ solution casting is reported in this work. The surface morphology of ZnO nanoparticles combined with cellulose fibers and the distribution of these ZnO-cellulose composites on the paper surface were characterized by scanning electron microscopy. The results showed that ZnO nanoparticles are easily and uniformly dispersed in the CNC. The ZnO-cellulose composite nanofluids were prepared by dispersing the composites in isopropanol as a base fluid. To determine the protective potential of these coatings, the chemical and mechanical properties of coated papers after dry heat and UV accelerated aging were measured. Also, a good color stability of the paper coated by the nanocomposites was observed through colorimetric measurements . The paper coated with ZnO-cellulose composites was found to possess antibacterial and antifungal activity against five common fungi (Aspergillus niger, Aspergillus Versicolor, Rhizopus nigricans, Saccharomycetes, Mucor) observed in the archive or museum and two bacteria (Staphylococcus aureus and Escherichia coli) in common life.

Cellulose-based aerogel beads for efficient adsorption- reduction- sequestration of Cr(VI)

Meng Li,Chunxia Tang,Shaohai Fu,Kam Chiu Tam,Yongzhong Zong

The reduction and sequestration of toxic Cr(VI) via a one-step process in an aqueous solution is critical to eliminate its environmental risk. In this study, amine functionalized cellulose-based aerogel beads (CGP) was developed for simultaneous and efficient adsorption- reduction- sequestration of Cr(VI). CGP showed a maximum Cr(VI) adsorption capacity of 386.40 mg/g at 25 °C due to its strong electrostatic attraction towards Cr(VI). The simultaneous Cr(VI) adsorption- reduction- sequestration performance of CGP over a wide Cr(VI) concentration range was examined. The mechanism was investigated in-depth via the analysis of adsorption kinetics , XPS spectra, and FTIR spectra. Moreover, the Cr immobilization stability of CGP after adsorption was evaluated in simulated neutral, acidic, and alkaline conditions. The effect of pH, temperature, ionic strength and the presence of interfering ions on CGP adsorption performance were investigated by batch adsorption experiments. Fixed-bed column adsorption study was performed to explore the application potential of CGP beads in a wastewater treatment process.

Adsorption behavior of hexavalent chromium in aqueous solution by polyvinylimidazole modified cellulose

Xiong Peng,Zongcheng Yan,Lihua Hu,Rongze Zhang,Shujun Liu,Aili Wang,Xiwen Yu,Li Chen

Developing multifunctional adsorbent materials is an effective solution to hexavalent chromium (Cr (VI)) pollution. In this study, 3D macroporous materials with the synergetic advantages of cellulose and polyvinylimidazole were fabricated through a homogeneous method, and served as effective adsorbents for Cr (VI) elimination in aqueous solution. The physicochemical properties of the designed materials were studied by SEM, FTIR, 13 C NMR, XPS , and CHN element analysis, and the results confirmed that imidazole groups were successfully grafted onto the macroporous cellulose. The influences of different water chemistry conditions, including contact time, temperature, initial solution pH value, and coexisting ion concentration, on the adsorption performance of the modified cellulose adsorbents were studied, and the corresponding adsorption mechanism was explored. The optimized adsorbent showed a fast adsorption rate (0.12 g/(mg∙min)), and a high adsorption ability (134 mg/g). The adsorption process was spontaneous and conformed to Langmuir isotherm and pseudo-second kinetic models. The Cr (VI) uptake mechanism of the designed materials was primarily controlled by electrostatic attraction, ion exchange, and redox. These results suggest that cellulose modified with imidazole groups is a promising candidate for the adsorption and detoxification of Cr (VI).

Porous carbon derived from K2B4O7 and phytic acid-modified cellulose for supercapacitors

Shao Yutian,Guan Qing,Ding Chunyan,Liu Yulin,Liu Mingwei

Herein, B, P co-doped porous carbon (PC BP ) was prepared from K 2 B 4 O 7 and phytic acid-modified cellulose via chemical activation and used as electrode materials for supercapacitors. Of which, K 2 B 4 O 7 not only acts as a source of boron, but also as an activation agent in the process of activation. The electrochemical properties of porous carbon materials were significantly improved by doping P and B. Compared with the porous carbon doped by B, PC BP shows almost higher specific capacitance and better rate performance. When evaluated as supercapacitor electrode materials in 6 M KOH electrolyte under two-electrode test systems, the as-prepared PC BP exhibits an excellent electrochemical performance: a high specific capacitance of 214 F g −1 at 0.05 A g −1 , a good rate capability of 142 F g −1 at 20 A g −1 and 2.7% capacitance loss after 10,000 cycles. Thus, the co-doping of B and P holds great promise for improving the specific capacitance and rate capability, which is attributed to the synergistic effect of B and P co-doped. Graphical abstract

Chitosan/cellulose-based beads for the affinity purification of histidine-tagged proteins

Mingcong Shao,Lili Xiu,Haijiang Zhang,Jianying Huang,Xingwen Gong

Chitosan/cellulose-based beads (CCBs) for the affinity purification of histidine-tagged proteins were prepared from chitosan/cellulose dissolved in ionic liquid as a solvent, and their structures were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The affinity purification was used to separate hexahistidine-tagged (his-tagged) enhanced green fluorescent protein (EGFP) from Escherichia coli. The results showed that Zn2+–CCB exhibited more specific adsorption capacity toward the target protein compared with Ni2+–CCB and Cu2+–CCB. The maximum adsorption of EGFP was 1.84 mg/g of Zn2+–CCB, with 90% purity under the optimized conditions (ionic strength (1.0 M NaCl), pH (7.2) and imidazole concentration (500 mM)). In addition, a regeneration method for the sorbent was further developed by washing with ethylenediaminetetraacetic acid disodium and then reimmobilizing with metal ions. This technique is an alternative method for the purification of his-tagged proteins, making the process more economical, fast, stable, and large batch.

Physicochemical and adsorption characteristics of activated carbons from cellulose, xylan and lignin

Runzhen Lai,Jun Hu,Yahui Sun,Ping Lu

Activated carbons (AC) were prepared from the three major components (cellulose, xylan , and lignin) of lignocellulosic biomass by H 3 PO 4 activation. Physicochemical characterizations reveal that as compared with AC from lignin (AC-L), AC from carbohydrates, especially AC from xylan (AC-X), have higher-developed porous structure, more disordered carbon, and more active O-containing and P-containing functional groups. The adsorption of methylene blue (MB) on all ACs followed Langmuir isotherm and pseudo-second-order kinetic models . Primarily due to its superior porosity, AC-X possessed the highest adsorption capacity for MB of 666 mg/g. AC from cellulose (AC-C) and AC-L followed with the adsorption capacities of 498 mg/g and 395 mg/g. The adsorption of MB was endothermic and AC-X had the highest feasibility and spontaneity. AC-X also exhibited superior adsorption capacities for the adsorption of typical heavy metals, although the superiority is much weaker as compared with that for MB. This research suggests the positive impact of carbohydrates, especially hemicellulose , in the precursors of the ACs on their adsorption performances.

Dual-stimuli sensitive nanogels fabricated by self-association of thiolated hydroxypropyl cellulose

Junjun Tan,Hongliang Kang,Ruigang Liu,Deqian Wang,Xin Jin,Qinmei Li,Yong Huang

A new type of cellulose derivative was synthesized by means of conjugating cysteamine to hydroxypropyl cellulose (HPC) and the degree of thiol groups could be controlled by the feed ratio of the reactants. The thiolated HPC (HPC–SH) maintains the thermosensitivity of HPC and the thiol groups on the HPC chain can be oxidized to disulfide bonds. Cytotoxity tests performed on MG-63 cells proved that HPC–SH is not harmful to the cells. Nanogels can be fabricated by the self-association of HPC–HS in the solution at 45 °C and then oxidation of thiol groups to disulfide bonds occurs to stabilize the associated structure. The crosslinking degree of the nanogels could be controlled by the substitution degree of thiol groups (–SH) in the thiolated HPC. The hydrodynamic radius of the nanogels can be tuned by adjusting the degree of crosslinking and the concentration of the initial thiolated HPC solution in the self-association process. The hydrodynamic radius of the nanogels can be changed with the temperature and the dissociation process can happen by adding the reducing agent dithiothreitol (DTT). The dual-stimuli sensitive nanogels may have potential applications in controlled drug release, transfer switch device and sensors.

A versatile cellulose nanocrystal‑carbon dots architecture: Preparation and environmental/biological applications

Ruyi Li,Fangyuan Liang,Xianyun Hu,Huiyang Bian,Chao Deng,Farzad Seidi,Baiyang Zhang,Huining Xiao,Yuqian Liu

In this work, a versatile cellulose nanocrystal‑carbon dots (CNC-CDs) architecture is prepared and applied in environmental remediation and biological sensing. The citric acid (CA) is employed to extract CNCs and in-situ synthesize blue-emissive CDs. The carboxyl-rich surface of CNC-CDs enables the chelation of Hg 2+ and fluorescence quenching of CDs, realizing the detection and adsorption of Hg 2+ with a film comprised of the architecture. The limit of detection (LOD) is measured as 12.8 nM with satisfying retention efficiency. The versatility of CNC-CDs is demonstrated by the fabrication of a fluorescence resonance energy transfer (FRET) sensor using m-tetrakis(4-sulfonatophenyl)porphine (TSPP) as FRET acceptor and Fe 3+ receptor. Fluorescence of the sensor is responsive to Fe 3+ in a ratiometric manner, which significantly contributes to the visualized and sensitive Fe 3+ detection (6.9 nM). In combination with excellent biocompatibility, the FRET sensor is capable of imaging intracellular Fe 3+ .

Cellulose nanofibrils reinforced films without chemical modification, hydrophobic, high elongation, and foldability

Lanjie Shi,Lei Kang,Jie Gong,Xi Zhang,Jianming Liao,Lihuan Mo,Jun Li

Cellulose nanofibrils (CNF) films are generally regarded as promising alternatives for non-biodegradable plastics films. However, the shortcomings of high hydrophilic performance, low elongation and poor folding endurance continue to pose challenges in commercial application. In the present study, we established controllable reflectance CNF films by applying a facile and scalable poly (butylene adipate-co-terephthalate) (PBAT)/SiO 2 nanoparticles (NPs) reinforced strategy in a free chemical modification manner. CNF/PBAT films have the favorable combination of hydrophobicity, elongation and folding endurance. The results reveal a significant improvement in the hydrophobic properties of CNF/PBAT films (water contact angle >80°), as well as a 3 times improvement in folding resistance (1210 cycles), a 3.7 times improvement in tensile strength (89.8 MPa) and controlled reflectance properties. Additionally, we examined the hiding power and color difference of the CNF/PBAT films, and explored the underlying principle for the enhanced hydrophobicity, folding resistance, elongation and reflectance. Finally, the CNF/PBAT films exhibited stable comprehensive performance after we applied the films in drinking straws. The present study provides a facile strategy to prepare hydrophobic, folding resistant, reinforced and reflectance-controlled CNF films and could promote industrial use in the fields of glass film, beverage appliances, packaging, and flexible electronic devices.

Enhanced Conductivity of Anion-Exchange Membrane by Incorporation of Quaternized Cellulose Nanocrystal

Xia Cheng,Jianchuan Wang,Yunchuan Liao,Cunpu Li,Zidong Wei

High ion conductivity of anion-exchange membrane is essential for the operation of alkaline anion-exchange membrane fuel cell. In this work, we demonstrated an effective strategy to enhance the conductivity of anion-exchange membrane (AEM), by incorporation of quaternized cellulose nanocrystal (QCNC) for the first time. Morphology observation demonstrated a uniform distribution of QCNC within QPPO matrix, as well as a clear QCNC network, which led to significant enhancement in hydroxide conductivities of composite membranes, for example, 2 wt % QCNC/QPPO membrane possessed a conductivity of 160% (60 mS cm–1, @80 °C) of that of QPPO. Furthermore, H2/O2 cell performance of membrane electrode assembly based on 2 wt % QCNC/QPPO AEM showed an excellent peak power density of 392 mV cm–2 at 60 °C without back pressure, whereas that of neat QPPO AEM was only 270 mV cm–2.

Fluorescent Microspheres Based on Sodium Carboxymethyl Cellulose Hydrogel for Optical Temperature Measurement

Bin Li,Fan Zhang,Xin Yan,Xuenan Zhang,Yong Zhao,Tonglei Cheng

Ionic Liquids Grafted Cellulose Nanocrystals for High-Strength and Toughness PVA Nanocomposite

Li Wang,Jie Hu,Yunxiao Liu,Jie Shu,Hao Wu,Zhaozhao Wang,Xiaolong Pan,Ning Zhang,Lijuan Zhou,Jianming Zhang

The surface functionalization of cellulose nanocrystals (CNCs) is of significant importance for promoting its diverse applications. However, the efficient strategy reported so far for cation functionalization of CNCs remains limited owing to the electrostatic attraction between cationic modifiers and electronegative CNCs. Herein, a cationized CNC (CNC-LA-IL) has been successfully prepared in aqueous media by grafting the [VBIm][BF4], a kind of ionic liquid (IL), on the surface of a sulfated CNC using lactic acid (LA) as a linker molecule. This surface functionalization not only converts the negative charge of CNC suspensions to a positive charge (zeta potential reversed from −35 to +40 mV) but also leads to enhanced thermal stability and redispersibility of the dried CNC. To examine the reinforcing effect of IL-modified CNCs, poly(vinyl alcohol) (PVA)/CNC-LA-IL nanocomposite films were further prepared by the solution casting method. To one’s surprise, the as-prepared PVA/CNC-LA-IL films exhibit extraordinary improvement in both the tensile strength (92%) and the toughness (166%) with only a 0.3 wt % CNC loading. This study provides a green and facile method to achieve ionic liquids grafted CNCs for high-performance nanocomposites.