INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yi-Ying Ma,Ze-Long Lu,Yun-Zhu Xing,Wei-Shi Zheng,Chun-Guang Liu
In this case, various characterization technologies have been employed to probe dissociation mechanism of cellulose in N , N -dimethylacetamide/lithium chloride (DMAc/LiCl) system. These results indicate that coordination of DMAc ligands to the Li + –Cl − ion pair results in the formation of a series of Li x (DMAc) y Cl z (x = 1, 2; y = 1, 2, 3, 4; z = 1, 2) complexes. Analysis of interaction between DMAc ligand and Li center indicate that Li bond plays a major role for the formation of these Li x (DMAc) y Cl z complexes. And the saturation and directionality of Li bond in these Li x (DMAc) y Cl z complexes are found to be a tetrahedral structure. The hydrogen bonds between two cellulose chains could be broken at the nonreduced end of cellulose molecule via combined effects of basicity of Cl − ion and steric hindrance of [Li (DMAc) 4 ] + unit. The unique feature of Li bond in Li x (DMAc) y Cl z complexes is a key factor in determination of the dissociation mechanism.
研究领域:
化学
·
材料科学
·
高分子科学
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DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2013
·
IF 3.479
Ziyu Qin,Li Ji,Xueqiong Yin,Li Zhu,Qiang Lin,Jinming Qin
Various sodium bacterial cellulose sulfates (SBCS) were prepared via the homogeneous sulfation of bacterial cellulose (BC) with a SO 3 /pyridine (Py) complex in a dimethyl acetamide/lithium chloride solution. The SBCSs were characterized using Fourier transform infrared spectroscopy, X-ray diffraction (XRD), carbon nuclear magnetic resonance spectroscopy, gel permeation chromatography, elemental analyses, and thermal gravimetric analyses. A variety of conditions (including various amounts of SO 3 /Py, temperatures, and reaction times) were utilized to obtain SBCSs with DS values that ranged from 0.10 to 1.50. The XRD profiles indicated that the SBCSs had a cellulose II analog polymorphous structure. The differences between BC and microcrystalline cellulose (MC) were studied in their respective reactions. BC is more reactive than MC in both the sulfation and depolymerization processes. The order of reactivity for C OH is C6 > C2 > C3 for both BC and MC. Cellulose sulfates with DS values >0.31 were soluble in deionized water.
研究领域:
生物材料学
·
化学工程
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DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2020
·
IF 4.244
Xin Gao,Meng Li,Heng Zhang,Xiaoning Tang,Keli Chen
In this study, regenerated cellulose (RC) thin films were obtained using parenchyma cellulose from large clustered bamboos which were endemic to Xishuangbanna area in Yunnan province, China. The bamboo parenchyma cells were separated from their low-temperature (140 ℃ of the maximum temperature) kraft pulps through multi-screening. The cellulose was dissolved in N,N -dimethyl acetamide (DMAc) solvent with LiCl amount from 6 % to 10 %, then regenerated in the glycerol-water solution. X-ray diffraction analysis indicated the crystalline forms of RC films were transited from cellulose I to cellulose II. TGA analysis suggested that lower LiCl usage take an advantage on the higher thermal stability of the RC films. The DMAc-related solvent with a relatively lower LiCl dosage displayed a stronger capacity of cellulose dissolution, shed light on its considerable industrial application prospects and facilitated the high value-added utilization of waste biomass resources.
研究领域:
材料科学
·
生物质资源利用
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DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Hong Wang,Jing Han,Minghui Du,Zhaohui Yin,Qingqing Wang,Xiaolong Ge,Zhen Yin,Jianxin Li
In the presence of an electric field (EC), persulfate-mediated sulfate radicals ( SO 4 · − ) are an attractive wastewater treatment technology because they are cleaner and more complete. However, uncertainty in the degradation mechanism and high electrode cost limit the application of this technology. In this paper, a novel flat-plate multichannel carbon membrane (CM) coupled with persulfate (PDS) was used to construct an integrated system of electrocatalytic membrane reactor (ECMR) and for the efficient degradation of N , N -dimethylacetamide (DMAC). The system focused on the synergistic degradation mechanism of EC/CM/PDS and the removal efficiency of DMAC. The results indicated that cathodic degradation (92.4 %) was more effective than anodic degradation (11.3 %). Comparative experiments were conducted with different treatment processes, and the results indicated that the removal rate of DMAC by the EC/CM/PDS system was 6.4 and 10.5 times greater than that of the EC/CM and CM/PDS systems, respectively. In addition, the optimal operating parameters of ECMR were systematically investigated. The sulfate radicals ( SO 4 · − ), hydroxyl radicals ( ˙ OH ), and singlet oxygen ( 1 O 2 ) generated during the electrochemical cathodic activation of PDS by CM were confirmed to be the main reasons for the efficient degradation of DMAC through electron spin resonance (ESR) assay and quenching experiments. This work provides insights for analyzing the mechanism of action of EC/CM/PDS and designing efficient electrochemical advanced oxidation techniques to remove difficult-to-degrade organic pollutants.
研究领域:
环境科学
·
化学工程
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DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Jingwen Tang,Chengling Bai,Xiaoyi Huang,Jiang Yuan,Shuili Yu,Li'an Hou
Co-solvent-assisted interfacial polymerization is commonly used to enhance the characteristics of polyamide (PA) thin film composite (TFC) membranes. However, its application to PIP-TMC systems is less frequent, and there is limited understanding regarding the role of co-solvents. In this article, we selected N, N-dimethylacetamide (DMAc), 1-butanol, acetonitrile (ACN), and N-methyl pyrrolidone (NMP) with similar solubility parameters to modulate the PIP-TMC IP process. The introduction of co-solvents can enhance the mutual solubility between aqueous and organic phases, which promotes the PIP diffusion rate and contributes to high-performance NF membranes characterized by smaller pore sizes. Notably, membranes prepared with DMAc demonstrated enhanced retention of divalent ions (MgCl 2 : from 41 % to 83.4 %) and maintained high permeability (46.6Lm −2 h −1 at 0.3 MPa), whereas excessive co-solvents could damage the performance. Additionally, Molecular dynamics (MD) simulations show that the co-solvent regulates PIP diffusion rate with its diffusion rate by hydrogen bonding with the PIP molecules and moving together with PIP. Significant variations in the PIP diffusion rate resulted in a wrinkled morphology on the membrane surface. This study offers fresh insights into the selection of co-solvents for co-solvent-assisted TFC NF membrane preparation, presenting a straightforward, facile, and commercially viable approach for achieving high-performance NF membranes.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Wenzhong Ma,Taiyu Li,Chao Jiang,Peng Zhang,Li Deng,Rong Xu,Qi Zhang,Jing Zhong,Hideto Matsuyama
Pervaporation (PV) performance of polyimide (PI) membranes has been attempted for the recovery of high concentrations of aprotic solvents, such as N, N-dimethyl formamide (DMF) and N, N-dimethylacetamide (DMAc). In this work, we explored the effect of chain structure on the solvent resistance and pervaporation performance of hydrophilic pyromellitic dianhydride (PMDA) and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) based polyimide membranes. According to the Hansen solubility parameters and membrane formation morphologies, we selected five aprotic solvent resistant PI membranes with different chain structures. It was found that the swelling degrees in DMF and DMAc was principally determined by the elasticity modulus of the PI membrane, and was significantly influenced by the polymer chain structure. The flexible linkages (such as –O CH 2 and CH 2 ) suppressed the PI chain packing, which resulted in the d -spacing and fractional free volume ( FFV ) of PMDA based PI membrane was higher than BTDA based PI membrane. BTDA-BZD membrane had the highest elasticity modulus together with the lowest d -spacing value (4.68 Å) due to its symmetric intermolecular interaction and rigid chain structure. PV experiments were conducted with DMF/water and DMAc/water mixtures over a wide range of temperatures (30–60 °C) with 90 wt% solvent concentration. The BTDA based PI (M4) composite membrane showed the highest separating factor around 275 at 30 °C in DMAc solution, which was much higher than in DMF solution (the separating factor is about 70). Furthermore, the chemical and thermal stability test for the PI composite membranes in the presence of the feed solvent under the PV process demonstrated the excellent separation stability in DMAc solution.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 9
·4955-4968
·
IF 3.809
Li Weijie,Zhang Fengying,Wang Weiku,Li Yinhui,Liu Yaodong,Lu Chunxiang,Zhang Zhengfang
Abstract
Cellulose was dissolved in LiCl/DMAc solvent system at various concentrations. Using rheological measurements, we observed that the cellulose solution becomes gelled upon heating and jelly-like during cooling. Interestingly, while phase separation occurs during heating (from room temperature to higher) along with a sol–gel transition, and this transition is irreversible, the cooling (from room temperature to lower) induced solution property transition from more viscous to more elastic is completely reversible. The structural changes of cellulose solution during heating and cooling cycles are in situ monitored by infrared spectroscopy, and we found that the temperature of the solution affects the interactions among DMAc, lithium cations, chloride anions, and the hydroxyl groups in cellulose chains. While heating induces phase separation and gelation of cellulose solutions, cooling simply turns the solution into a reversible jelly status. Also, when cellulose concentration increases, the gelation temperature caused by heating becomes significantly lower. Possible mechanisms of the rheological transitions of cellulose/LiCl·DMAc solutions during either heating or cooling are proposed in this study. Graphical abstract
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Mian Hu,Jiayi Zheng,Zhiheng Ye,Yufan Jin,Xinyu Pan,Jiahui Huang,Yage Zhang,Junliang Wang,Zhong-Ting Hu,Zhiyan Pan
Traditional approaches for wastewater treatment in chemical industry primarily emphasize the degradation of organic pollutants, resulting in excessive waste of carbon resources and carbon oxide emissions. This work studied on subcritical catalytic water oxidation for conversion N,N-Dimethylacetamide (DMAC), a significant organic polar solvent and extensively utilized in the chemical industry, into acetic acid. In the presence of zirconia catalyst, the parameter factors such as different crystalline forms of ZrO 2 , reaction temperatures, residence times, oxidation coefficient (O/C), and alkaline additives on the degradation efficiency of DMAC and the corresponding product distribution and acetic acid selectivity were examined and optimized systematically. Under a condition of 320 °C, 30 min, O/C = 1, NaOH = 50 mmol/L, and t -ZrO 2 = 5 wt%, the DMAC conversation rate reached 98.00 % with acetic acid yield of 37.25 % (selectivity of 93.97 %). In addition, the carbon balance of all intermediates was analyzed, and conformed that the carbon originating from DMAC was mainly converted into CO 2 and acetic acid. This work provides a new strategy on efficient conversion waste carbon resources into chemical product of organic acid, which is significantly contributed to carbon emission reduction worldwide.
研究领域:
环境科学
·
化学工程
·
催化反应
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhipeng Chen,Tao Wang,Chao Li,Mengxiang Fang,Wei Chen,Ximing Hu,Yan Shao,Zhihao Liu,Wei Zhang,Li Zhang,Wenyang Fan,Shaojuan Zeng
Lower regeneration energy and superior cyclic capacity have enabled biphasic absorbents great potential in the area of flue gas CO 2 capture. The liquid film mass transfer coefficient(k L ) is a vital parameter in the development of absorbents with efficient CO 2 absorption mass transfer performance, while the phase separation behavior of biphasic solutions could be an essential factor for the absorption mass transfer and the stability of absorber. However, systemic kinetic research towards biphasic absorbents, especially the impact of phase separation behavior, is limited. In this study, a typical amide-based biphasic absorbent diethylenetriamine(DETA)/diethanolamine(DEA)/N, N-dimethylacetamide(DMAC) which has achieved great reduction in regeneration energy, was selected as the subject of kinetic investigation in a wetted wall column. The CO 2 overall mass transfer coefficient(K G ) of DETA/DEA/DMAC exceeded other biphasic solvents, blended amine solution, and 40% K 2 CO 3 solution, with 3 times that of 40% K 2 CO 3 solution. Moreover, various operational conditions including absorption temperature, gas flow rate, and water content of solution were taken into account to build a multiple-condition kinetic mechanism to offer guidance for biphasic absorbents. Furthermore, phase separation behavior was revealed as the main blame for the deterioration in the liquid film chemical mass transfer process of biphasic solvents in the CO 2 absorption process, resulting in the k L of DETA/DEA/DMAC before phase separation decreased by 75.3% at the phase separation stage. Therefore, it is crucial to ensure that the CO 2 loading of the solution entering absorber is lower than the phase separation point in applications. After phase separation, DETA/DEA/DMAC split into the organic and aqueous phases, the k L of the aqueous phase gradually exceeded that of the organic phase as CO 2 loading increased for its higher chemical enhancement factor(E).
研究领域:
化学工程
·
环境科学
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产品关联
DOI
高影响因子
CELLULOSE
·
2025
·
IF 4.8
Zhao Yao,Wang Xueping,Li Bowen,Si Tian,Gao Xin,Peng Lincai,Zhang Heng
The cellulose catalytic oxidation system mainly comprises inorganic ion-based oxidants. Hence, the selective oxidation of C 6- primary hydroxy groups (C 6 -OH) of cellulose, catalyzed by piperidine free radicals, was limited to the homogeneous cellulosic system containing protic solvents or heterogeneous system. In this work, the use of the catalytic system containing 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl (4-AcNH-TEMPO) was extended to the cellulosic solution in N, N-dimethylacetamide (DMAc) and combined with chlorine dioxide. Results showed that the carboxyl content was 0.832 mmol/g. Meanwhile, the degree of polymerization decreased from 900 to 489. This study provides an effective route for the homogeneous selective oxidation of primary hydroxy groups in cellulose and explored its oxidation mechanism in DMAc solvent. Furthermore, studies showed that the reactive chlorine species- ClO·, Cl·, and ClO 2 played a crucial role in the oxidation process. The methodology developed here displayed great potential to be utilized to various biomolecules in aprotic solvents homogeneous system based on 4-AcNH-TEMPO as oxidation catalysts.
研究领域:
化学工程
·
材料科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Hong Wang,Qingqing Wang,Minghui Du,Xiaolong Ge,Zhaohui Yin,Peiyong Wang,Binzhi Zhang,Zhen Yin,Jianxin Li
Conventional electro-peroxone (EP) systems suffer from inefficient mass transfer that restricts the interfacial interaction between electrogenerated H 2 O 2 and dissolved O 3 . Herein, a novel EP membrane reactor (EPMR) was constructed by integrating O 3 aeration with permeable carbon membrane (CM) as both cathode and anode. The CM cathode (working electrode) has a porous structure and excellent electrical conductivity, allowing O 3 /O 2 -containing wastewater to flow through while occurring EP process. The water treatment performance was systematically evaluated through degradation of N, N-dimethylacetamide (DMAc) as the target pollutant. At a condition of 2.0 V applied voltage, 10 g L −1 Na 2 SO 4 electrolyte concentration, a permeation flux of 200 L m −2 h −1 , and an initial DMAc concentration of 100 mg L −1 , the EPMR system achieved a significantly higher chemical oxygen demand (COD) removal rate (59.1 %) compared to the conventional ozonation (19.70 %) and electrocatalysis (6.35 %). In the flow-through EPMR system, the yield of H 2 O 2 at 120 min was 16.77 mg L −1 , which is 9.64 times that of the flow-by mode (1.74 mg L −1 ). Meanwhile, the O 3 mass transfer coefficient reached 0.8561 min −1 , which was higher than flow-by (0.2439 min −1 ) modes, respectively. Electron spin resonance (ESR) analysis showed that the •OH contributed to approximately 40 % of COD removal in EPMR. The EP process and MR show a good mutual promotion effect. Specifically, CM cathode improves the mass transfer of O 2 and increases the production of H 2 O 2 via the oxygen reduction reaction (ORR). The increase in H 2 O 2 production, in turn, promotes the consumption of dissolved O 3 through the EP process and improves the gas–liquid mass transfer of O 3 , resulting in high DMAc degradation efficiencies. This study proposed an efficient method for DMAc wastewater treatment.
研究领域:
环境科学
·
废水处理
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Jiali Peng,Jianfei Yan,Qixuan Chen,Xia Jiang,Gang Yao,Bo Lai
To enhance the degradation of N, N-dimethylacetamide (DMAC) in aqueous solution, the natural mackinawite (NM) is introduced for catalytic ozonation in this study as it is an environmentally friendly catalyst with low cost and easy availability. The properties of the NM were initially characterized via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Then, impact factors including NM dosage, ozone gas concentration and initial pH were investigated and the optimal conditions (i.e., NM dosage = 3.5 g/L, ozone gas concentration = 300 L/min, initial pH = 6.8) were obtained in NM/O3 process. Besides, the superiority of the NM/O 3 process was confirmed by the experiments that the degradation efficiency of DMAC in the NM/O 3 process (i.e., 95.4%) was much higher than that in the zero-valent iron (ZVI)/O 3 process (i.e., 46.1%) and the synthetic FeS/O 3 process (i.e., 68.6%). Furthermore, the intermediate and possible degradation pathway of DMAC were proposed, and the biological toxicity of the intermediate was subsequently evaluated by the activated sludge . Finally, the mechanism of the NM/O3 process was proposed in this study based on control experiment and radical scavenging experiment. The extraordinary efficiency for DMAC degradation was found to be mainly caused by HO • of the reactive oxygen species (ROS) (i.e., HO • , O 2 •- and H 2 O 2 ) generated in the NM/O 3 process. Therefore, this study confirmed that NM was a high efficient catalyst for degradation the toxic and refractory pollutants in catalytic ozonation system.
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PubMed
高影响因子
危险品化学品经营许可证（带存储）