MOLECULES
·
2023
·Vol. 28
·期 22
·7671
·
IF 4.6
Liu Shi,Yiming Sun,Xian Li,Shuo Li,Bing Peng,Zhenzhong Hu,Hongyun Hu,Guangqian Luo,Hong Yao
A novel gas-pressurized (GP) torrefaction method at 250 °C has recently been developed that realizes the deep decomposition of cellulose in lignocellulosic solid wastes (LSW) to as high as 90% through deoxygenation and aromatization reactions. However, the deoxygenation and aromatization mechanisms are currently unclear. In this work, these mechanisms were studied through a developed molecular structure calculation method and the GP torrefaction of pure cellulose. The results demonstrate that GP torrefaction at 250 °C causes 47 wt.% of mass loss and 72 wt.% of O removal for cellulose, while traditional torrefaction at atmospheric pressure has almost no impact on cellulose decomposition. The GP-torrefied cellulose is determined to be composed of an aromatic furans nucleus with branch aliphatic C through conventional characterization. A molecular structure calculation method and its principles were developed for further investigation of molecular-level mechanisms. It was found 2-ring furans aromatic compound intermediate is formed by intra- and inter-molecular dehydroxylation reactions of amorphous cellulose, and the removal of O-containing function groups is mainly through the production of H2O. The three-ring furans aromatic compound intermediate and GP-torrefied cellulose are further formed through the polymerization reaction, which enhances the removal of ketones and aldehydes function groups in intermediate torrefied cellulose and form gaseous CO and O-containing organic molecules. A deoxygenation and aromatization mechanism model was developed based on the above investigation. This work provides theoretical guidance for the optimization of the gas-pressurized torrefaction method and a study method for the determination of molecular-level structure and the mechanism investigation of the thermal conversion processes of LSW.Keywords:lignocellulosic solid wastes;cellulose;gas-pressurized torrefaction;molecular structure;deoxygenation mechanism;aromatization mechanism
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Jianwei Guo,Shuang Zhou,Xiang Ma,Shaochun He,Di Chen,Fei Xie,Cheng Wang,Hui Yang,Wenjiang Li
With the requirement of sustainable development in modern society, it is urgent to develop the environmentally friendly adsorbents for selective filtration and separation of toxic dyes from hazardous wastewater. Herein, a stable, reusable, and highly compressible three-dimensional regenerated cellulose/polyethyleneimine composite aerogel (RC/PCA) was successfully prepared directly using cheap cotton pulp as raw material and N-methyl morpholine-N-oxide (NMMO) as the “green” solvent, in which the regenerated cellulose (RC) with hydroxyl groups converted from cotton can interact with polyethyleneimine (PEI) with amine groups. After further crosslinking of RC, PEI and glutaraldehyde (GA), the RC/PCA can be used to selectively absorb anionic dyes from the ternary mixed dye system, which maximal adsorption capacity for methyl orange (MO) can be up to 980.39 mg/g. Moreover, the obtained stable RC/PCA can be repeatedly used at least 50 times for the removal of MO (20 mg/L) with a high filtration efficiency of 99.8 %. The kinetics and isothermal adsorption data were described via the pseudo-second-order kinetic model and Langmuir model. Therefore, this research proposes a novel strategy for developing low-cost, highly efficient, regenerated cellulose-based adsorbents to extract organic dyes from wastewater for potential practical applications.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Jia Wei,Yan Long,Binqi Wang,Huizheng Wu,Hongshuai Gao,Yi Nie
In the ionic liquids (ILs) method for processing regenerated cellulose fiber (RCF), which is a high-performance ecologically benign product, metal ion impurities (such as Fe 3+ and Cu 2+ ) of cellulose might inevitably remain in the recycled ILs and coagulation bath. The presence of metal ions might negatively impact the properties of the manufactured RCFs and obstruct their applications, which are urgent to be made clear. For this research, the solvent for dissolving wood pulp cellulose (WPC) was 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) with various metal ion concentrations. The effect of metal ions in IL on the dissolution of cellulose was investigated by Molecular Dynamics simulations. Rheological analysis and degree of polymerization (DP) analysis were adopted to evaluate the influence on fiber spinnability of different spinning solution metal ion concentrations and various dissolving times. Further, the morphology and mechanical performances of the RCFs variation regulation were also thoroughly researched. The findings showed that the presence of metal ions in the spinning solution affected the DP, crystallinity, and orientation factor of RCFs, which will influence their stress more sensitively than the strain. These findings can serve as a practical guide for the commercial manufacture of emerging fiber.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Qiong Wu,Zhuoyu Wang,Baozheng Zhao,Ruiyang Zhao,Shitao Yu,Lang Huang
Promoted ethylene glycol (EG) yield from cellulose hydrogenolysis is achieved via using Nickel-tungsten doped carbon catalysts prepared from glucose ( x %Ni- y %WO x -GC T ). Synchronously metal loading and carbon formation endow the catalyst excellent catalytic performance and high stability. Mechanistic investigations of the effects of metal loading and BrØnsted acid on EG yield are conducted. Increasing W loading promotes the content of polymerized WO x and consequently increases the amount of polytungstate species, thus lead to an improved BrØnsted acid content. Results reveal that promotion of B/L acid facilitates cellulose hydrolysis and suppresses isomerization of glucose to fructose. Besides, high W loading is beneficial for reduction of WO x to form W 5+ , producing oxygen vacancies to promote retro aldol condensation (RAC) of glucose to form acetaldehyde alcohol (an important intermediate for EG). By adopting the optimized 9%Ni-12%WO x -GC 700 catalyst, a 100% cellulose conversion with a high EG yield of 65% is obtained due to the synergistic interactions between BrØnsted acid, W 5+ and Ni 0+ active sites.
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CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Weiquan Wang,Xuewen Liu,Fan Guo,Yuxuan Yu,Jinqing Lu,Yiling Li,Qiaoyun Cheng,Jinping Peng,Goubin Yu
The development of renewable, hydrophobic, and biodegradable intelligent packaging materials as an alternative to petroleum-based plastic products has become a new research focus in recent years, but remains a challenge. Herein, regenerated cellulose/curcumin composite films were fabricated by dispersing hydrophobic curcumin uniformly in a hydrophilic cellulose matrix using an aqueous alkali/urea solvent based on the pH-driven principle of curcumin. In addition, a unilateral hydrophobic modification was carried out using chemical vapor deposition of methyltrichlorosilane to obtain Janus structure. The composite films exhibited high transparency in the visible light spectrum , excellent antioxidation, thermal stability , mechanical strength , gas barrier properties, and antibacterial activity . Furthermore, the films demonstrated the capability to lower the overall levels of volatile basic nitrogen in stored fish. The color of the films shifted from a pale yellow to a reddish-brown over time during storage. The composite films can be completely degraded after approximately 98 days in soil with an average environmental temperature of 29 °C. This work provided a facile strategy to prepare biodegradable cellulose/curcumin films with Janus structure as packaging materials which could preserve the freshness of food products while offering visual monitor of their freshness in real-time.
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ChemistrySelect
·
2023
·Vol. 8
·期 37
·e202302048
·
IF 2.1
Shuying Yang,Hui Jiang,Le Duan,Kaixuan Zuo,Ineza Urujeni Gisèle,DuoDuo Li,Yuyang Yao,Deli Xiao
Graphical We systematically investigated the effects of the magnetic fluid dispersion medium, size and concentration of magnetic nanoparticles, type and viscosity of cellulose on the temperature sensitivity of the magnetic fluid. We also studied the mechanism of temperature sensitivity, and the results showed that hydrogen bond interactions play an important role. Combining magnetic materials with environmentally sensitive polymers to develop intelligent magnetic fluids that respond to external stimuli has become a new research hotspot. At present, the bottlenecks in the development of temperature-sensitive materials are the complex composition, and its properties in different laboratories vary greatly. Moreover, despite extensive research on magnetic fluids, there remains a dearth of systematic investigation into temperature-sensitive intelligent magnetic fluids. In this study, we utilized a UV-visible spectrophotometer to measure the change in transmittance of different magnetic fluid solutions with temperature variation. We systematically investigated the effects of the magnetic fluid dispersion medium, size and concentration of magnetic nanoparticles, type and viscosity of cellulose on the temperature sensitivity of the magnetic fluid. We found that compared with Hydroxypropyl Methyl Cellulose (HPMC) (type I), HPMC (type II) modified magnetic fluid has better stability and a higher phase transition temperature. Moreover, with the increase of the concentration of magnetic fluid, the phase transition temperature is higher. In addition, the lower the viscosity of HPMC-modified magnetic fluid, the better the stability and the higher the phase transition temperature. We also studied the mechanism of temperature sensitivity, and the results showed that hydrogen bond interactions play an important role. This research will facilitate the use of temperature-sensitive smart magnetic fluids for biomedical application.
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CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Dan Luo,Gaofeng Sun,Yilin Wang,Xuan Shu,Jie Chen,Mengya Sun,Xiuyu Liu,Chao Liu,Huining Xiao,Tingting Xu,Hongqi Dai,Xuelian Zhou,Chen Huang,Huiyang Bian
In order to alleviate the resource and environmental problems caused by plastic film materials , the development of biodegradable cellulose-based films is crucial. Inspired by the strengthening mechanism of cellulose-lignin network from wood, carboxylated lignin (CL) was isolated using maleic acid (MA) pretreatment catalyzed by metal chlorides. Compared with pure MA, the presence of metal ions yielded CL with high carboxyl content (0.34 mmol/g), small size and good dispersibility. CL was then composited with CNF to prepare various CL/cellulose nanofibrils (CNF) composite films. When the addition of ferric chloride was 0.3 mmol/g maleic acid , the corresponding composite films exhibited highest tensile strength (180.0 MPa), Young's modulus (13.0 GPa) and excellent ultraviolet blocking rate (97.0 %). Meanwhile, the interaction forces measured by atomic force microscope showed that the binding between CNF and various CLs (276–406 nN) was higher than that between pure CNFs (202 nN), verifying that CL enhanced the mechanical properties of composite films. In summary, this work constructs a super-strong network between CL and CNF synergistically mediated by metal ion crosslinking and hydrogen bonding , which can be a promising alternative to replace conventional plastics in multiple areas.
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高影响因子
Foods
·
2023
·Vol. 13
·期 1
·132
·
IF 5.2
Xiangzheng Yang,Jingshan Rao,Chaoyi Shen,Huan Lian,Da Wang,Di Wu,Kunsong Chen
The preparation of active packaging loaded with antimicrobial, antioxidant, and other functional agents has become a hot topic for food preservation in recent years. In this field, active fiber films based on spinning methods have attracted the interest of researchers owing to their high specific surface area, high porosity, high loading capacity, and good controlled release capacity. In the present work, neatly arranged ethyl cellulose (EC)/polyvinyl-pyrrolidone (PVP) fibrous films loaded with natamycin as an antimicrobial agent were prepared by microfluidic spinning. The encapsulation efficiency of natamycin was more than 90% in each group and the loading increased with increasing natamycin content. According to the characterization results of the natamycin-loaded EC/PVP fibrous films, hydrogen bonding was formed between natamycin and EC and PVP in the fibrous films. Meanwhile, the water contact angle of the fibrous films was increased, suggesting the improved hydrophobicity of the films. In the in vitro bacterial inhibition experiments, the active fiber films loaded with natamycin showed good antimicrobial activity, which could significantly inhibit the growth of gray mold. In conclusion, N-EC/PVP fibrous films with antimicrobial activity prepared by microfluidic spinning showed good potential in the field of active packaging.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Lidong Chen,Jin Wu,Gaojian Zhu,Chao Liu,Tingting Xu,Liulian Huang,Weibing Wu,Jiaqi Guo,Huining Xiao,Hongqi Dai,Chen Huang,Zhen Zhang,Huiyang Bian
A large number of polluting substances, including chlorinated organic substances that were highly stable and hazardous, has been emitted due to the rapidly developing chemical industry, which will affect the ecological environment. Nanocellulose aerogels are effective carriers for adsorption of oil substances and organic solvents , however, the extremely strong hydrophilicity and poor mechanical properties limited their widespread applications. In this study, TEMPO-oxidized cellulose nanofibrils was modified with 2, 4-toluene diisocyanate (TDI) and 4,4′-diphenylmethane diisocyanate (MDI) to prepare strong and hydrophobic aerogels for oil adsorption. The main purpose was to evaluate and compare the effects of two diisocyanates on various properties of modified aerogels. It was found that the modified aerogel had better hydrophobic properties, mechanical properties and adsorption properties. In particular, the modified aerogel with TDI as crosslinker showed a better performance, with a maximum chloroform adsorption capacity of 99.3 g/g, a maximum water contact angle of 131.3°, and a maximum compression stress of 36.3 kPa. This study provides further evidence of the potential of functional nanocellulose aerogel in addressing environmental pollution caused by industrial emissions.
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高影响因子
POLYMER
·
2023
·
IF 4.6
Zhi-Xiong Fei,Ji Lan,Jingrui Sun,Chenxiao Yin,Ling-Ying Shi
Flexible ionic conductors with excellent mechanical properties , stability and conductivity from green and efficient fabrication technology have great application potentials in the intelligent devices. In this work, we reported an ionic conductor fabricated from the polymerization of the polymerizable deep eutectic solvent (PDES) reinforced by the hydroxyethyl cellulose (HEC). The PDES with the cationic hydrogen bond acceptor as the polymerizable unit was synthesized from the methacrylate of the 2-choline bromide (ChBrMA) as hydrogen bond acceptor and the glycerol (Gly) as hydrogen bond donor. The PDES has solubility to dissolve the HEC and thus the HEC-reinforced poly (PDES) ionic conductors were successfully prepared by one step photopolymerization . The addition of HEC enhanced the mechanical strength of poly (PDES)-based ionic conductor. The ionic conductors present the characteristics of good elasticity, puncture resistance, heat resistance and low volatility, and their electrical conductivity reached 2 × 10 −2 S/m at room temperature . Finally we assembled a flexible sensor which can accurately detect the movement of human fingers and monitor the change of environmental temperature in real time, demonstrating their potentials in the multifunctional sensors with long-term durability.
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CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Siwen Bi,Zhuang Zhang,Zhenzhen Yang,Zitong Shen,Jiahui Cai,Jintao Hu,Haoxiang Jin,Tianhao Qiu,Peng Yu,Bin Tan
Due to the highly environment-dependent biodegradation and uncontrolled degradation period, the long-run feasibility and effectiveness of biodegradable polymers are extensively questioned to solve plastics waste accumulation and pollution problems. This work physically incorporated lipase PS from Burkholderia cepacian on cellulose nanocrystals (CNC) and embedded it in polycaprolactone (PCL) to construct stable and controllable interfacial microenvironment between CNC and PCL for the reinforcement and controllable self-driven biodegradation. The physical adsorption of lipase PS on CNC was studied by monitoring the surface charge and particle size. FT-IR spectra confirmed the successful incorporation of lipase PS and CNC. Compared with CNC, protein-modified CNC had a higher maximum thermal decomposition temperature of 345 °C and lower interfacial tension of 11 mN/m with PCL which provided PCL composites with higher nucleation efficiency and tensile elongation of 1086 % at break. In addition, only 0.67 % embedded lipase PS completely hydrolyzed PCL membranes in <140 h. The post-compression molding at 80–100 °C had negligible influence on the lipase activity, which indicated that CNC could protect the lipase from inactivation in polymer extrusion and compression. This work also highlighted protein-modified CNC as a new technology for polymer reinforcement.
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Meng Liu,Lingling Fan,Changqi Feng,Zikui Bai,Weilin Xu,Jie Xu
The widespread utilization of disposable plastic straws has caused serious white pollutions. Cellulose-based paper straws are considered as a commercial alternative to plastic straws, which are limited by their inferior water stability and mechanical performance as well as harmful waterproof coating. Cellulose nanofibers have been proven to be an effective solution for improving the performance of cellulose-based straws. It is urgent to develop a facile, scalable and low-cost method of preparing cellulose nanofibers for straw production. Herein, cellulose microfiber/nanofiber blends are prepared using a green and low-cost H 2 O 2 oxidation method. Highly degradable composite straws are fabricated via rolling up a wet film of cellulose microfibers/nanofibers/lignin and then baking at 140 °C. During the baking process, the molten lignin could infiltrate into the pores between the microfibers/nanofibers to enhance the mechanical strength and water stability of the straws. Compared with commercial paper straws, the proposed straws exhibit superior mechanical strength, good water stability, low cost and facile natural degradability. The cellulose/lignin straws are expected to be used widely to address the white pollutions caused by plastic straws.
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