INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Liangyun Sun,Juan Han,Jiacong Wu,Wenrui Huang,Yuanyuan Li,Yanli Mao,Lei Wang,Yun Wang
The special molecular structure and properties of cellulose restrict its resource utilization. In this work, two kinds of common inorganic salt hydrates (ZnBr 2 ·RH 2 O and FeCl 3 ·RH 2 O) were used to pretreat microcrystalline cellulose (MCC) by magnetic stirring method at temperatures below 80 °C. It was found that while high temperatures could shorten the dissolution time of MCC, while inorganic salt hydrates with either low water (ZnBr 2 ·3.5H 2 O and FeCl 3 ·5H 2 O) or high water (ZnBr 2 ·5H 2 O and FeCl 3 ·8H 2 O) content can prolong the dissolution time of MCC. The reactivity of regenerated cellulose (RC) after dissolution was evaluated by enzyme hydrolysis reaction. Moreover, ZnBr 2 ·4H 2 O and FeCl 3 ·6H 2 O have better pretreatment effect. The structure and surface morphology of MCC before and after pretreatment were investigated by XRD , FT-IR, SEM , AFM and TGA. The MCC was converted from cellulose Ⅰ to cellulose II through the pretreatment. With the extension of dissolution time, the strength of hydrogen bond and thermal stability of RC were both slightly weakened, Moreover, the crystallinity and degree of polymerization (DP) of RC decreased, and the surface morphology of RC was more rougher, more uneven and dispersed compared with the smooth and compact MCC. The adsorption rate curves showed that RC-ZnBr 2 ·4H 2 O was more conducive to the adsorption of cellulase , thereby accelerating the rate of RC hydrolysis. Furthermore, ZnBr 2 ·4H 2 O is a well reusable pretreatment solvent that can maintain a good pretreatment effect on cellulose after five cycles.
研究领域:
化学工程
·
材料科学
·
生物材料
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
E-POLYMERS
·
2017
·Vol. 17
·期 6
·463-470
·
IF 0.949
Yongqian Nie,Xuanxi Leng,Yixue Jiang,Shigan Chai,Jinzhi Zhang,Qichao Zou
Unsaturated polyester resins (UPR) were prepared by the melt condensation method based on adipic acid, o-phthalic anhydride, maleic anhydride and ethylene glycol in the presence of PSS-(2,3-propanediol)propoxy-heptaisobutyl substituted (PSS-POSS) or/and 9 wt% [(6-oxide-6H-dibenz(c,e)(1,2)oxaphosphorin-6-yl)methyl]butanedioic (DDP). We synthesized UPR containing DDP (DDP-UPR) and UPR containing both DDP and PSS-POSS (DDP-PSS-POSS-UPR series). The chemical structures of the modified polyesters were characterized and confirmed by Fourier transform infrared (FTIR) and 31 P nuclear magnetic resonance ( 31 P NMR). The thermal stability and flammability behaviors of UPR were evaluated by thermogravimetric analysis (TGA) and limited oxygen index (LOI) and the vertical burning test. The morphology of residual char of UPR was shown by scanning electron microscopy (SEM). The results indicate that the incorporation of PSS-POSS has little influence on the thermal stability of DDP-UPR, but enhances the flame retardance of DDP-UPR, and when the PSS-POSS content reaches 10 wt%, the DDP-PSS-POSS-UPR has better flame retardance.
研究领域:
材料科学
·
聚合物化学
·
消防安全工程
✓ 已验证
产品关联
DOI
高影响因子
HIGH TEMPERATURE MATERIALS AND PROCESSES
·
2021
·Vol. 40
·期 1
·389-396
·
IF 0.826
Yingwei Xu,Tingting Zhang,Li Zheng,Ailing Zou
KBaPO 4 :Eu 2+ /Sm 3+ phosphor was synthesized via the high-temperature solid-phase reaction method. The structural properties, surface morphology, and optical properties of the synthesized samples were obtained by the X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and fluorescence measurements. The XRD patterns indicate that the crystal structure of KBaPO 4 has not been changed by co-doped with two rare-earth ions. Under the excitation of 400 nm, the Eu 2+ and Sm 3+ co-doped KBaPO 4 phosphors showed typical emission peaks at 430 (blue), 562 (yellow), and 600 nm (red). Meanwhile, with the increase of the Sm 3+ content, the photoluminescent (PL) emission intensity of Sm 3+ increased until the content reaches 0.12. However, the PL intensity of Eu 2+ ions gradually decreased, which indicated that there was a possible energy transfer between the two ions. Therefore, the obtained results indicated that Eu 2+ /Sm 3+ co-doped KBaPO 4 is a promising phosphor for the use in white light-emitting diodes with near ultraviolet chips.
研究领域:
材料科学
·
光电技术
·
固体物理
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Zhong Sun,Yihan Yin,Yupeng An,Chao Deng,Ziyu Wei,Zijiang Jiang,Xixin Duan,Xiaohui Xu,Jing Chen
A cost-efficient and simple method, grafting sodium sulfonate groups (−SO 3 Na) onto carboxymethyl cellulose (CMC), was developed to form hydrogel adsorbents for the removal of poisonous metals including Cu(Ⅱ) and Zn(Ⅱ) from wastewater. In this work, cellulose-based hydrogels (CMC-g-P(AA-co-SS)) were prepared using acrylic acid (AA) and sodium styrene sulfonate (SS). FTIR, XPS , SEM , and EDX were employed to analyze the surface morphology and structure of CMC-g-P(AA-co-SS). The results revealed that the synergistic effect of −SO 3 Na and carboxylate groups (−COO − ) facilitated the adsorption of heavy metals. Moreover, introducing AA and SS enhanced the swelling degree of CMC hydrogels. The results of adsorption experiments showed that high adsorption efficiencies were obtained for Cu(Ⅱ) and Zn(Ⅱ) (200.44 mg/g and 192.28 mg/g, respectively) within 180 min. The adsorption isotherm and kinetics indicated that the monolayer chemical adsorption dominated the process. After 5 cycles, the adsorption activity of CMC-g-P(AA-co-SS) remained high, with the adsorption capacity for Cu(Ⅱ) and Zn(Ⅱ) being 93.3% and 78.3% of the original, respectively. Thus, the CMC-g-P(AA-co-SS) is a promising adsorbent candidate for the removal of poisonous metals from wastewater.
研究领域:
环境科学
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Cong Wang,Gang Li,Hongchen Guo
Compared with the mainstream approaches of doping the active metal in the MOFs structure and post-synthetic modification, it is more convenient to directly use the coordinatively unsaturated metal sites of MOFs for catalytic reactions. Herein, two forms of Ni-MIL-77 (1D Ni-MIL-77 and 3D MIL-77) were prepared using one-pot method and characterized by ICP-AES, XRD, FT-IR, XPS and SEM. Among them, 1D Ni-MIL-77 without high temperature heat treatment exhibited a better heterogeneous catalytic ethylene dimerization activity that was up to 989.6 g pro. /(g cat. ·h) (TOF=5544 h −1 ) and the selectivity of 1-butene could reach 93.3% at the optimal conditions. In addition, a probable Cossee-Arlman-like mechanism was proposed. By studying the catalyst structure after reaction, it was found that the reason for limited reuse was the hydrolysis products of the co-catalyst covered the catalysts.
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2021
·
IF 6.475
Shang Wu,Yang Yang,Tingwei Wang,Jiadi Sun,Yinzhi Zhang,Jian Ji,Xiulan Sun
Antibiotic resistance in Salmonella enterica serovar Typhimurium ( S . ser. Typhimurium) has become a critical safety hazard in food. Sublethal environmental stresses can influence resistance in Salmonella during food processing. This study simulated environmental stresses in food processing. The antibiotic resistance of three strains of S . ser. Typhimurium (the ATCC 14028 strain and two wild-type isolates from chicken and pork product processing) was evaluated under different pH levels (5.0, 5.5, 6.0, 8.0, and 9.0). Also, dynamic changes in resistance with treatment duration under cold (4 °C, −20 °C) and heat (55 °C) treatment were studied. The results showed that acid and alkaline stresses reduced the resistance of S. ser. Typhimurium to eight antibiotics; meanwhile, the resistance of meropenem (MERO) increased. The minimal inhibitory concentration (MIC) of MERO was increased 16- to 64-fold. With acid or alkaline stress, the extracellular ATP content increased, and the scanning electron microscopy (SEM) result clearly revealed the appearance of wrinkles and holes on the outer membrane of Salmonella . These observations imply changes in membrane permeability, which may decrease the antibiotic resistance of Salmonella . Cold or heat stress increased the resistance of S . ser. Typhimurium to tetracycline, cefotaxime, ceftazidime, nalidixic acid, azithromycin, and ampicillin; the MIC increased 2- to 4-fold. The antibiotic resistance only changed when cold and heat stresses occurred over a certain period of time and remained unchanged when the stress persisted. This study reports on the ability of S. ser. Typhimurium to develop antibiotic resistance after environmental stresses. It can provide valuable information for meat processing to improve interventions and risk management.
研究领域:
微生物学
·
食品科学
·
抗菌素耐药性
·
环境压力
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2014
·
IF 3.552
Jing-Chuan Song,Zhong-Yuan Lu,Zhao-Yan Sun
3-Aminophenol/formaldehyde (AF) resin colloidal spheres with narrow size distribution and high nitrogen content are synthesized in the presence of urea. The obtained particles that indicated by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) are spherical morphology and uniform. It can be further carbonized into carbon spheres preserving high nitrogen percent. The particle size is tunable from 300 nm to 850 nm by appropriately varying the concentration of precursor or water/ethanol volume ratio. Even using the water as an only solvent, we can also obtain spherical particles with different size. Typically, the nitrogen percent in the obtained polymer and carbon particles is as high as 10.39 wt% and 8.95 wt%, respectively. The typical surface area of resulted carbon particles obtained from nitrogen adsorption measurement is 459 m 2 g −1 . X-ray diffraction demonstrates the obtained carbon spheres are amorphous , which are expected to have practical application in the field of energy devices. The method can be considered as a low cost and facile method for mass production.
研究领域:
材料科学
·
化学工程
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Li Peng,Xiaohan Xu,Xun Yao,Hua Liu,Xuehong Gu
A series of novel hierarchical ZSM-5 zeolite membranes with tunable mesopore sizes have been prepared successfully by using amphiphilic organosilane 3-[(trimethoxysilyl) propyl]octyldimethyl-ammonium chloride (TPOAC) as the mesogenous template and part of the Si source. The effects of several synthesis parameters, such as the TPOAC/SiO 2 ratio, synthesis temperature and crystallization time, on the microstructures and rejection performance of the hierarchical ZSM-5 zeolite membranes were systematically investigated. Multiple techniques, such as XRD , SEM, N 2 adsorption techniques, TEM, IR, 13 C MAS NMR and 29 Si MAS NMR were employed for the characterizations. The filtration of dextran in water shows that the membranes have molecular weight cutoff (MWCO) ranging from 9500 to 943,000, corresponding to the molecular size in the range of 4.5–37 nm. The sharp increase in the rejection of dextran with the increase of molecular weight indicated narrow pore size distribution of the membrane. These results show that the hierarchical mesoporous ZSM-5 zeolite membranes have a great potential for ultrafiltration with high performance.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Aiping Chang,Zeli Ye,Zhenquan Ye,Jinfeng Deng,Jieying Lin,Changjer Wu,Hu Zhu
Sphingan WL gum (WL), a kind of exopolysaccharides , is produced by Sphingomonas sp. WG. In this study, citric acid (CA) crosslinked WL hydrogel films were firstly developed for potential wound dressing application. ATR-FTIR and TG results suggested the occurrence of esterification crosslinking. SEM analysis showed that this aided covalent crosslinking could prevent their porous structures from collapsing when swelling. Due to the deprotonation of carboxyl groups, the water absorption capacity of WL-CA hydrogel films increased with the increase of pH (maximum swelling ratio = 38 g/g). The covalent crosslinked swollen WL-CA hydrogels exhibited certain hydrolytic stability, high porosity (>60%), moderate tissue adhesion, and good rheological property (G′ > G″, G′ up to 2 kPa). WL-CA-CIP hydrogel films loaded with antibiotic ciprofloxacin (CIP) showed sustained drug release properties, long-lasting antibacterial activity , and superior biocompatibility. All the results indicated that WL-based hydrogels were potential candidates for wound dressing applications.
研究领域:
材料科学
·
药剂学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Hao Zhu,Shunyan Ning,Zengzhiqiang Li,Xinpeng Wang,Toyohisa Fujita,Yuezhou Wei,Xiangbiao Yin
Here, a nano disc-shaped bimetallic organic framework (NbCo-piperazine) was prepared by the solvothermal method for the activation of PMS for the degradation of contaminants. The effects of Nb/Co ratio, synthesis time and temperature on the morphology, structure and performance of the NbCo-piperazine catalyst were characterized by XRD, FT-IR, SEM-EDS and TEM. The optimum conditions for NbCo-PZ to activate PMS degradation of tetracycline were investigated by adjusting the dosage of catalyst, tetracycline concentration, pH and PMS concentration. The catalytic performance of NbCo-PZ in the presence of co-existing anions (Cl − , NO 3 – , HCO 3 2– , H 2 PO 4 − ) was also evaluated. XPS explained that cyclic changes in the valence states of Nb 4+ /Nb 5+ and Co 2+ /Co 3+ accelerated the activation of the PMS degradation process. EPR results showed the presence of free radicals (SO 4 ·− , ·OH and O 2 ·− ) and non-free radicals ( 1 O 2 ) in the degradation process, with free radicals playing a major role in the degradation process. The degradation rate of tetracycline after three cycles was 92.2%. In addition, NbCo-piperazine showed good catalytic performance for other organic pollutants such as methyl blue, tylosin tartrate and tetracycline with the degradation rate of 97.8%, 95.2% and 95.5%, respectively. Moreover, it also has good catalytic properties in various water systems such as river water and sea water.
研究领域:
环境化学
·
催化
·
水处理
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Shiwei Feng,Chengping Zhang,Hengdao Quan
As an environmentally friendly cleaning agent, Z -1-chloro-3,3,3-trifluoropropene (HCFO-1233zd( Z )) can realize industrial production by the isomerization of HCFO-1233zd( E ). Herein, various isomerization catalysts with different structures, compositions and acid properties were prepared through the fluorination of γ-Al 2 O 3 with CHF 3 by controlling the activation conditions. For the first time, the catalysts for HCFO-1233zd( E ) isomerization were systematically studied by XRD, N 2 physisorption, XPS, SEM, MAS NMR spectroscopy, NH 3 -TPD and py-IR. The active site of this reaction was revealed and the catalyst deactivation mechanism was proposed. It turned out that HCFO-1233zd( E ) isomerization prefers to occur at Lewis acid sites with moderate density and strength. The amorphous particles composed of γ-Al 2 O 3 , Al 2 O 3 (F) and α-AlF 3 ( R 3 ¯ c ) at 450 °C exhibit highly catalytic activity for HCFO-1233zd( E ) isomerization. After 100 h evaluation, it was found that residual γ-Al 2 O 3 can be fluorinated by HCFO-1233zd( E ) to form needle-like structures which could induce the amorphous Al 2 O 3 (F) particles to reorganize and give cubic structures, where the Lewis acid properties were enhanced, leading to catalyst deactivation.
研究领域:
催化
·
化学工程
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Yanan Yang,Yu Zhang,Hong Zheng,Baichao Zhang,Qi Zuo,Kaiyue Fan
A key challenge in trace heavy metals removal from drinking water by adsorption technology is to achieve high adsorption capacity and rapid uptake speed of adsorbent. Herein, we report a functionalized double modified covalent organic framework (DMTD–COF–SH) bearing high-density sulfur and nitrogen chelating groups provided simultaneously by 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and 1,2-ethanedithiol, which was prepared via a facile one-pot thiol-ene “click” reaction. PXRD , FTIR, XPS, SEM, BET and 13 C MAS NMR confirmed their successful graft, and DMTD was found to be more easily grafted on the COF surface layer than 1,2-ethanedithiol. The as-prepared DMTD–COF–SH showed remarkable adsorption capacity and ultrafast uptake dynamics to trace heavy metals owing to the synergistic effects resulting from densely populated sulfur and nitrogen chelating groups within ordered COF mesopores and at the COF surface. On the basis of the drinking water treatment units standard NSF/ANSI 53–2020, when the adsorbent dosage was 10 mg/30 mL and 20 mg L −1 calcium ions coexisted, the lead concentration decreased from initial 150 μg L −1 to 2.89 μg L −1 within 10 s, far below the allowable limit of world health organization (WHO) drinking water standard (10 μg L −1 ), and the maximum adsorption capacity meeting the standard attained 14.22 mg g −1 . The adsorbent also exhibited excellent stability, wide applicable pH range and outstanding adsorption performance for coexisting trace lead, mercury, cadmium, chromium (VI) and copper in tap water, indicating that the DMTD–COF–SH material has excellent application prospect for trace heavy metals removal from drinking water.
研究领域:
环境科学
·
材料科学
·
水处理
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）