查找使用阿拉丁产品的科研文献

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.

Preparation of green cellulose diacetate-based antibacterial wound dressings for wound healing

Xiao Chuang,Zhang Ge,Liang Wencheng,Wang Zhaochuang,Lu Qiaohui,Shi Weibin,Zhou Yan,Guan Yong,Lang Meidong

Managing wounds is a growing universal problem and developing effective wound dressings to staunch bleeding and protect wounds from bacterial infections is an increasingly serious challenge. In this work, a remolding electrospinning nanofiber three-dimensional structure wound dressing (CCP) was prepared with superhydrophilicity, high water absorption and absorbing capacity, excellent hemostatic capacity and antibacterial ability, and biocompatibility to promote wound healing. Polyhexamethylene guanidine hydrochloride (PHMG) was grafted to cellulose diacetate (CDA) wound dressing surface through an amide reaction. A water contact angle analysis demonstrated that CCP wound dressing could be beneficial to promote wound exudate management effectively with rapid absorption of water within 0.2 s. In vitro hemo- and cytocompatibility assay showed that a CCP wound dressing had no significant hemotoxicity or cytoxicity. Specifically, CCP wound dressings could be beneficial to accelerate wound hemostasis and further reduce mortality caused by uncontrolled bleeding. Furthermore, CCP wound dressings have an excellent antibacterial ability, which could be beneficial to inhibit wound inflammatory over-reaction and promote normal wound healing. Combined together, the prepared wound dressing in this research effort is expected to have high-potential in clinical applications.

Preparation of high-performance cellulose composite membranes from LiOH/urea solvent system

Yinke Liu,Shuman Xu,Mengfan Jing,Yuan Wei,Hua Deng,Qiang Fu

Ultrapermeable polyamide nanofiltration membrane formed on a self-constructed cellulose nanofibers interlayer

Jinfeng Kong,Yuzhang Zhu,Dianyu Dong,Jian Jin

Improving the water permeance of polyamide nanofiltration (NF) membranes without the simultaneous loss of rejection is highly desired but remains a challenge. In this work, we prepared an ultrapermeable polyamide NF membrane containing an in-situ -formed cellulose nanofibre (CN) interconnected network film between a polyamide active layer and ultrafiltration (UF) membrane support through direct addition of the CN to a piperazine aqueous solution for interfacial polymerization. Such in-situ -formed CN interlayer with high porosity can provide a large number of channels for water transport. Compared with the polyamide active layer directly supported by the UF support, the polyamide active layer supported by the CN interlayer can contribute a more effective area for water permeation. Consequently, the polyamide NF membrane exhibited a pure water permeance up to 35.7 L m −2 h −1 bar −1 while maintaining salt rejection to Na 2 SO 4 of >97%. This permeance is 2.5 times greater than that of the membrane without the CN interlayer.

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+ .

Electrospun Poly(N-isopropylacrylamide)/Ethyl Cellulose Nanofibers as Thermoresponsive Drug Delivery Systems

Juan Hu,He-Yu Li,Gareth R. Williams,Hui-Hui Yang,Lei Tao,Li-Min Zhu

Fibers of poly(N-isopropylacrylamide) (PNIPAAm), ethyl cellulose (EC), and a blend of both were successfully fabricated by electrospinning. Analogous drug-loaded fibers were prepared loaded with ketoprofen (KET). Scanning and transmission electron microscopy showed that the fibers were largely smooth and cylindrical, with no phase separation observed. The addition of KET to the spinning solutions did not affect the morphology of resultant fibers, and no drug particles could be observed to separate from the polymer matrix. X-ray diffraction demonstrated that the drug was present in the amorphous physical form in the fiber matrix. There are significant intermolecular interactions between KET and polymers, as evidenced by IR spectroscopy and molecular modeling . Water contact angle measurements proved that the PNIPAAm and PNIPAAm/EC fibers switched from being hydrophilic to hydrophobic when the temperature was increased through the lower critical solution temperature of 32°C. In vitro drug release studies found that the PNIPAAm/EC blend nanofibers were able to synergistically combine the properties of the 2 polymers, giving temperature-sensitive systems with sustained release properties. In addition, they were established to be nontoxic and suitable for cell growth. This study demonstrates that electrospun-blend PNIPAAm/EC fibers comprise effective and biocompatible materials for drug delivery systems and tissue engineering.

Composite scaffolds of graphene oxide enriched carboxymethyl cellulose for thermal energy storage

Jianxin Xie,Qing Li,Hairui Li,Yongbo Su,Yuchi Dong,Dahe Yang,Huazhi Wang

As a by-product of the petroleum industry, paraffin wax (PW) has a huge stock. In the context of today's fossil fuel shortages, the effective utilization of PW is of particular significance. In this paper, a simple and size-controllable method was used to synthesize graphene oxide (GO) enriched carboxymethyl cellulose (CMC) aerogel beads with several millimeters, and the beads prepared were applied to load PW for fabricating composite phase change materials (PCMs). The possible synthesis mechanism of CMC and GO enriched CMC porous spheres aerogel beads was discussed. The structure and thermal energy storage properties of the composites were studied. The results showed that, compared to CMC beads, incorporation of GO into CMC beads could optimized its structure, and improve its loading ratio ω of PW from 82.8 % to 92.9 %, corresponding to the melting enthalpy of the composite increased from 161.4 J/g to 181.0 J/g. Besides, the composite has good thermal stability and thermal reliability. Given the simplicity and ease of control of its synthesis method, and the excellent thermal energy storage capacity of the synthesized PW/CMC@GO, this study opens a promising avenue for enhancing PW utilization while providing a high-performance thermal energy storage material with simple and efficient production.

Synthesis of surface quaternized cellulose nanofibrils for high-performance antibacterial composite films

Pengfei Wang,Lianjie Zhao,Linghua Xu,Jialong Wen,Tongqi Yuan,Xuefei Cao,Shaoni Sun

Cellulose nanofibrils (CNF) are promising nanomaterials with considerable potential in packaging materials due to their excellent mechanical properties and sustainability. However, the limited functionality of CNF restricts their applications in functional packaging materials. Herein, a series of surface quaternized CNF (CCNF-Q n ) with tunable alkyl chain lengths (C 8 –C 16 ) were synthesized by first surface chloroacetylation using vinyl chloroacetate, and then quaternization with tertiary amines. The CCNF-Q n were comparatively characterized and the quaternary ammonium groups were successfully introduced onto the surface of the CNF. The XPS results revealed that the N/C atomic ratios of the CCNF-Q n range from 0.016 to 0.022. The CCNF-Q n were further utilized to improve the mechanical and antibacterial properties of the polyvinyl alcohol (PVA) films. At 5.0 wt% CCNF-Q n incorporation, the tensile strength and elongation at break of the composite film reached 53.7 MPa and 229.7 %, respectively. The composite films with longer alkyl chains achieved nearly 100 % inhibition against Escherichia coli and Staphylococcus aureus . This work provides a new route for the synthesis of surface quaternized CNF, which show excellent antibacterial performance and have promising application prospects in high-performance packaging materials.

Interfacial Engineered Cellulose-Based HIPPEs for Thermal Energy Storage and 3D Printing

Qi Dai,Jiayi Lv,Yanpeng Cheng,Sining Huang,Hao Li,Zhaolin Yang,Mengqi Zhu,Long Bai,Zhiguo Li,Yang Liu,Siqi Huan

The stabilization of phase change materials (PCMs) in high internal phase emulsions (HIPEs) remains particularly challenging due to their inherent properties, significantly hindering their application in functional materials. Here, we introduce a versatile strategy in which oppositely charged cellulose nanofibrils (CNF) and didodecyl dimethylammonium bromide (DDAB) cooperate to construct PCM-in-water high internal phase Pickering emulsions (HIPPEs). The stabilization mechanism relies on a dual barrier: (i) electrostatic adsorption of CNF/DDAB complexes at the oil–water interface forms a dense and reversible interfacial film; (ii) a percolating CNF network in the continuous phase suppresses droplet migration through steric hindrance and viscoelasticity. Consequently, the emulsions remain stable over 30 days at room temperature, these HIPPEs suit diverse oils (including difficult-to-stabilize liquid paraffin) with up to 92% internal-phase volume, serving as green templates/3D printing inks and expanding the fabrication window for programmable HIPPEs in latent-heat storage and thermal management.

Mild and recyclable ethylenediamine pretreatment for bacterial cellulose fermentation and lignin valorization

Wenchao Li,Bin Xu,Mingfang Xu,Yue Wu,Zhihua Liu,Bingzhi Li,Cheng Zhong,Shiru Jia

In this study, a novel mild and recyclable ethylenediamine (EDA) pretreatment method was developed. This pretreatment process efficiently eliminated lignin and facilitated the recovery of pretreatment reagents. Under optimized conditions at 70 °C, more than half of lignin was removed from the corn stover (CS). Consequently, the enzymatic hydrolysis of glucose and xylose achieved yields of 82.1% and 50.4%, respectively. Notably, the recovered EDA was efficiently reused and maintained comparable pretreatment efficiency even after five rounds of recovery. The pretreated CS was effectively used for bacterial cellulose fermentation without requiring additional detoxification steps. Furthermore, the analysis of EDA lignin (EL) revealed the presence of numerous amino groups introduced into the lignin structure. Subsequently, EL was used in the polyurethane (PU) foam preparation. The results revealed that EL-based PU foam featured higher compressive strength, density, thermal stability, and adsorption capacity for dyes and heavy metal ions compared with alkali lignin-based PU foam.

Evaluating performance of CrCl3-catalyzed ethanol pretreatment of poplar on cellulose conversion

Meishan Fan,Jun Li,Zhu Liu,Caiqun Li,Hongdan Zhang,Jun Xie,Yong Chen

As green and effective depolymerization processes, CrCl 3 and CrCl 3 -catalyzed ethanol pretreatment were comprehensively investigated to improve cellulose conversion from pretreated residues in poplar in the present study. The influence of pretreatment temperature on delignification , structural characteristics of lignin, and the yield of glucose and ethanol was comparatively analyzed to emphasize the synergy effect of CrCl 3 and ethanol solvent. Particularly, CrCl 3 -catalyzed ethanol pretreatment at 200 °C resulted in the pretreated substrates with >94% removal of hemicellulose and lignin, consequently reaching 88.88% and 56.11% yields of glucose and ethanol, respectively. Lignin's structural change was observed by Gel permeation chromatography and 2D nuclear magnetic resonance spectroscopy and its relationship with the efficiency of enzymatic hydrolysis and fermentation was determined. Results indicated that the increased pretreatment temperature enhanced the lignin depolymerization with smaller molecular weight , fewer β-O-4 linkages, and higher S/G ratio, especially in CrCl 3 -catalyzed ethanol pretreatment, which was positively associated with poplar cellulose conversion. In addition to offering a comprehensive illustration of the sugar/ethanol generation during CrCl 3 -catalyzed organosolv pretreatment, this work also provided theoretical support for biofuel and biochemical production from poplar.