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    25 August 2021, Volume 41 Issue 4 Previous Issue    Next Issue
    Preparation and Corrosion Resistance of Tannin Acid/Toughened Shellac Resin Composite Coating
    Chunyin LI, Kun LI, Yanlin SUN, Yiwen LIU, Hong ZHANG, Fuhou LEI
    2021, 41 (4):  1-9.  doi: 10.3969/j.issn.0253-2417.2021.04.001
    Abstract ( 84 )   HTML ( 22 )   PDF (775KB) ( 93 )   Save

    In order to improve the toughness of shellac(SHL) resin, eleostearic acid(EA) was added to shellac resin through Diels-Alder reaction to prepare toughened shellac(TS) resin, and its structure was analyzed by gel chromatography(GPC), infrared spectroscopy(FT-IR) and 13C nuclear magnetic resonance(13C NMR). And then, tannic acid(TA) was added to prepare SHL-TA, and TS-TA composite coating. The effects of TA and EA on the anti-corrosion properties of shellac resin coating were analyzed by electrochemical workstation, neutral salt water resistance and neutral salt spray(NSS) resistance tests. The results showed that the TS modified by EA through the Diels-Alder reaction exhibited good toughness. When the weight ratio of SHL and EA was 1.8:1, the elongation at break of TS-3 coating was as high as 381.81%. In addition, the hydrophobicity of shellac coating was increased by the modification of EA, and its static water contact angle reached 95.01°.The addition of TA could improve the adhesion of the coating on the metal substrate, and the combined action of TA and EA could enhance the anti-corrosion of SHL coating. The best corrosion protection system was TS-3-TA coating. After immersion in 3.5% NaCl for 48 h, the polarization resistance of the coating was still 36.3 kΩ, far more higher than that of other coatings. And the time of neutral salt water resistance and neutral salt spray(NSS) resistance tests of TS-3-TA, which was prepared in alkali system, was 120 h and 168 h.

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    Preparation and Application of Lignin-based Intumescent Flame Retardant
    Mengke LIANG, Jing CHEN, Peng DAI, Xiaofeng MA, Meng ZHANG, Zhenyang LUO
    2021, 41 (4):  10-16.  doi: 10.3969/j.issn.0253-2417.2021.04.002
    Abstract ( 113 )   HTML ( 39 )   PDF (4186KB) ( 93 )   Save

    Lignin-based intumescent flame retardant(Lig-T) with carbon source, acid source and gas source was synthesized successfully by grafting nitrogen and phosphorus elements. The structure of the flame retardant Lig-T was proved by Fourier transform infrared spectrometer(FT-IR), elements analysis and X-ray photoelectron spectroscopy(XPS). The Lig-T was added to the epoxy resin with different mass fractions to obtain Lig-T/EP composite material. Thermogravimetric analysis, underwriters laboratories 94(UL-94) vertical buring test, oxygen index(LOI) test and cone calorimetry(Cone) test were used to investigate the thermal stability and flame retardancy of composite materials. The results showed that when the mass fraction of the Lig-T was 20%, the composite material 20% Lig-T/EP could reach the UL-94 V-0 level, the oxygen index value was as high as 28.5%, and the mass fraction of the residue increased from 14.8% to 20.2%.With the increase of the mass fraction of Lig-T, the total amount of heat release and the total amount of smoke released during the combustion process of the composite material decreased.

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    Antibacterial and Antioxidant Activities of Two Citrus Essential Oils and Their Main Components
    Huazheng CHEN, Kai ZHU
    2021, 41 (4):  17-22.  doi: 10.3969/j.issn.0253-2417.2021.04.003
    Abstract ( 79 )   HTML ( 12 )   PDF (508KB) ( 87 )   Save

    Orange oil, tangerine oil and limonene were used as target samples to study their scavenging capacities on ABTS+·, DPPH· and O2-· and total antioxidant capacity(FRAP value), as well as their antioxidant abilities in vivo and inhibitory abilities to Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The results showed that tangerine oil had the best scavenging capacity on ABTS+· and DPPH·, their IC25 values were 1.481 and 24.824 g/L, respectively; limonene had the best scavenging effect on O2-·, and the scavenging rate was 32.86% at 0.8 g/L. The ferric ion reducing antioxidant power(FRAP) values of limonene, orange oil and tangerine oil were close to each other and weaker than those of BHA. At the mass concentration of 100 mg/L, the catalase(CAT) activities in Caenorhabditis elegans treated with tangerine oil and limonene were about 46 U/mg, which was 1.63 times of that in the untreated control group. Orange oil, tangerine oil and limonene had a relatively good inhibitory effect on S. aureus and E. coli. The inhibitory effect of tangerine oil on S. aureus was close to limonene, and the diameter of inhibition zone was about 11 mm. Orange oil, tangerine oil and limonene had an excellent antioxidant activity in vitro and in vivo, and they were moderately sensitive to S. aureus.

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    Synthesis of Thujopsanone Catalyzed by Methyltrioxorhenium
    Sheng ZHANG, Kai ZHU
    2021, 41 (4):  23-28.  doi: 10.3969/j.issn.0253-2417.2021.04.004
    Abstract ( 49 )   HTML ( 7 )   PDF (544KB) ( 31 )   Save

    Thujopsanone was synthesized by oxidation reaction with thujopsene as raw material, dichloromethane as solvent, methyltrioxorhenium(MTO) as catalyst, 30% H2O2 as oxidant, and 3-methylpyrazole as co-catalyst. The effects of reaction conditions on the oxidation were studied. The optimized reaction were obtained as follows: the reaction temperature 30℃, the molar ratio of raw materals(n(H2O2): n(thujopsene)) 1:1, the reaction time 3 h, the catalyst amounts 0.3%(based on the weight of thujopsene, similarly hereinafter), the dosage of 3-methylpyrazole is 10%. Under these conditions, the yield of thujopsanone was 72.1%, and the conversion rate of thujopsene was 97.3%. The structure of the products was identified by GC-MS and FT-IR, and it was confirmed as wasthujopsanone.

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    High Efficient Separation of Cedrol from Chinese Fir Essential Oil
    Jiechen PAN, Yichuan TANG, Chengjie SHU, Baojun SHI, Kai ZHU, Wei LI
    2021, 41 (4):  29-34.  doi: 10.3969/j.issn.0253-2417.2021.04.005
    Abstract ( 59 )   HTML ( 14 )   PDF (440KB) ( 72 )   Save

    The light and heavy components were preliminarily separated from the cedar oil by vacuum distillation technology, and then the cedrol was separated by the method of freezing crystallization. The cedrol content in the isolate was analyzed by GC/MS to determine the optimal process. By studying the effects of different reflux ratio and total reflux time in the vacuum distillation process on the content of cedrol in the collected fractions, the final determination of vacuum distillation conditions were 2-3 kPa, total reflux time for 1h, reflux ratio of 3-7, the highest mass fraction of cedrol was 97.89%, the recovery rate was 87.52%. The collected highest fraction of cedrol was dissolved in ethanol, and then frozen and crystallized, and the purity of cedrol was finally reached 98.43%, the recovery rate was 83.61%.

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    Preparation and Slow-release Properties of Cinnamomum cassia Leaves Essential Oil/β-Cyclodextrin Microcapsules
    Guoliang LI, Xiangping LIU
    2021, 41 (4):  35-41.  doi: 10.3969/j.issn.0253-2417.2021.04.006
    Abstract ( 54 )   HTML ( 1 )   PDF (566KB) ( 43 )   Save

    In order to further broaden the application of Cinnamomum cassia leaves essential oil in food, feed and other fields, C. cassia leaves essential oil/β-cyclodextrin microcapsules were prepared by co-precipitation method with β-cyclodextrin as the wall material and C. cassia essential oil as the core material. The preparation conditions of microcapsules were optimized by orthogonal experimental design. Essential oil/β-cyclodextrin microcapsules were characterized by using gas chromatography-mass spectrometry(GC-MS) and Fourier transform infrared spectroscopy(FT-IR).The results showed that the suitable preparation conditions of microcapsules were wall-core ratio 6:1, temperature 50℃, time 4 h and stirring speed 1 000 r/min. The encapsulation efficiency of C. cassia essential oil of the obtained microcapsule was 74.17%. The GC-MS analysis showed that the main compositions of C. cassia essential oil were trans-cinnamaldehyde(81.39%), followed by o-methoxycinnamaldehyde(7.61%) and the main compositions of C. cassia essential oil in the microcapsule were also trans-cinnamaldehyde(78.68%) and o-methoxycinnamaldehyde(9.34%). FT-IR analysis showed that C. cassia leaves essential oil and β-cyclodextrin formed good inclusion complex. C. cassia leaves essential oil/β-cyclodextrin microcapsules had good thermal stability and slow-release properties.

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    Preparation and Characterization of Room Temperature Vulcanized Silicone Rubber Cross-linked by TiO2 Modified Dehydroabietic Acid
    Xinxin YANG, Zhaoyu JIANG, He LIU, Xujuan HUANG, Zhaosheng CAI, Shibin SHANG
    2021, 41 (4):  42-50.  doi: 10.3969/j.issn.0253-2417.2021.04.007
    Abstract ( 88 )   HTML ( 17 )   PDF (5315KB) ( 80 )   Save

    Dehydroabietic acid(DA) reacted with 3-glycidyloxypropyltriethoxysilane(GTS) to synthesize dehydroabietic acid-based cross-linking agent(DAG), and then DAG was combined with TiO2, catalyst dibutyltin dilaurate, and hydroxyl polysiloxane(PDMS) to fabricate the TiO2 modified dehydroabietic acid cross-linked the room temperature vulcanized silicone rubber(TiO2-DAG/RTVSR). The microscopic morphology, mechanical properties, thermal stability, and hydrophobicity of the samples were investigated. The results showed that DAG and TiO2 were uniformly dispersed in the dehydroabietic acid cross-linked silicone rubber. Compared with DAG/RTVSR-3 obtained by only adding DAG, when the addition of TiO2 was 7%, the tensile strength of the obtained TiO2-DAG/RTVSR-4 increased from 0.65 MPa to 0.98 MPa which increased by 50.8%, and the elongation at break increased from 250% to 317%.The 5% mass loss temperature of silicone rubber increased from 324.5℃ to 338.8℃ as the addition of TiO2 increased from 0% to 7%; and the swelling degree decreased, which indirectly reflected the increase in the degree of cross-linking.The contact angle gradually decreased with the increasing of TiO2 amount. These results indicated that the synergistic effect of dehydroabietic acid with rigid structure and TiO2 into the molecular chain of silicone rubber could effectively enhance the mechanical properties and thermal stability of room temperature vulcanized silicone rubber.In summary, silicone rubber with 7% TiO2 had the best performance.

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    Preparation of Anti-freezing Hydrogel Electrolyte and Its Application in Solid-state Supercapacitors
    Gaitong ZHANG, Xiaoli SONG, Fusheng YANG, Jingya NAN, Fuxiang CHU, Chunpeng WANG
    2021, 41 (4):  51-61.  doi: 10.3969/j.issn.0253-2417.2021.04.008
    Abstract ( 78 )   HTML ( 22 )   PDF (5088KB) ( 816 )   Save

    An anti-freezing hydrogel electrolyte(SPI-PVA-PAAm/LiCl) was synthesized, in which soybean protein isolates (SPI), ployvinyl alcohol(PVA) and acrylamide(AAm) were used as raw materials, ammonium persulfate(APS) was used as the initiator, N, N'-methylenebisacrylamide(MBAA) was used as the covalent crosslinker, LiCl was used as the electrolyte salt, and N, N, N', N'-tetramethylethylenediamine(TEMED) was used as the accelerator. Under low temperature conditions, the mechanical properties of the hydrogel electrolyte were analyzed, and the electrochemical properties of the solid-state supercapacitor based on this hydrogel electrolyte were investigated. The results showed that the hydrogel electrolyte had excellent anti-freezing propertity, because a certain molar concentration of LiCl reduced the freezing point of pure water in the hydrogel electrolyte and inhibited the crystallization behavior of water molecules. When the environmental temperature was reduced from 25℃ to -20℃, the hydrogel electrolyte still showed good mechanical properties and ionic conductivity. With the increase of the amount of LiCl, the compression performance of the hydrogel electrolyte firstly increased and then decreased, and the ionic conductivity increased. After 10 cycles of 80% compression strain, the stress retention rate, plastic deformation rate and energy loss coefficient of the hydrogel electrolyte with LiCl concentration of 5 mol/L(S-Li-5) were more than 100%, less than 25% and 0.33, respectively. The hydrogel electrolyte with LiCl concentration of 15 mol/L(S-Li-15) and CNTs were used to assemble the solid supercapacitor whose electrochemical performance was evaluated. When the ambient temperature was reduced from 25℃ to -20℃, the specific capacitance of assembled supercapacitor calculated by GCD curve could be maintained above 80%, and 0-70% compression strain could be withstood without damage, and the supercapacitor could still work normally; In addition, when the current density was 8.12 A/g, the capacitance retention rate of the device was higher than 91% after 1 000 cycles at -20℃.

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    Catalytic Performance of Carbon-based Solid Acid H-Al/AC in Glucose to 5-Hydroxymethylfurfural Reaction
    Yadong DU, Chunhui MA, Yu YIN, Wei LI, Sha LUO, Shouxin LIU
    2021, 41 (4):  62-68.  doi: 10.3969/j.issn.0253-2417.2021.04.009
    Abstract ( 52 )   HTML ( 15 )   PDF (2702KB) ( 41 )   Save

    A carbon-based solid acid catalyst(H-Al/AC) containing Brønsted(B) acid and Lewis(L) acid was prepared by H2SO4 sulfonation and AlCl3 immersion using coconut shell activated carbon(AC) as carrier. This catalyst was used to prepare 5-hydroxymethylfurfural(5-HMF) from glucose in a biphasic system(water/2-sec-butylphenol) by hydrothermal rection. The catalyst was characterized by SEM, BET, XRD, NH3-TPD and pyridine infrared to investigate the influence of preparation conditions on the structure and activity of the catalyst. The results showed that the catalyst activity reached the highest after being sulfonated with 98% H2SO4 and immersed in saturated AlCl3 solution for 4 h. The catalyst showed an amorphous carbon structure with the specific surface area of 1 139.31 m2/g, B acid amount 4.213 μmol/g and L acid amount 29.97 μmol/g, respectively. The catalytic performance of the prepared catalyst was investigated for the conversion of glucose to 5-HMF in biphasic system when the ratio of aqueous phase to organic phase was 1:2, and the results showed that the highest 5-HMF yield of 25.14% were obtained at 180℃ for 210 min with 0.025 g of catalyst. The reaction path of glucose conversion to 5-HMF was as follows: glucose was isomerized into fructose under the action of Lewis acid in the aqueous phase. Fructose was dehydrated under the catalysis of Brønsted acid to generate 5-HMF. 5-HMF was extracted into 2-sec-butylphenol(SBP), and the generated water was retained in the aqueous phase. The catalyst cycle stability test showed that the activity of the catalyst was 86% of the initial activity after repeated use for five times.

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    Preparation of Cellulose Nanofibril by the Pretreatment with Deep Eutectic Solvent System
    Guangrui MA, Ming HE, Guihua YANG, Weidong LI, Xingxiang JI, Jiachuan CHEN
    2021, 41 (4):  69-76.  doi: 10.3969/j.issn.0253-2417.2021.04.010
    Abstract ( 71 )   HTML ( 16 )   PDF (6026KB) ( 70 )   Save

    A choline chloride-urea(molar ratio of 1:2) based deep eutectic solvent(DES) system was used as a non-hydrolytic pretreatment media to prepare the cellulose nanofibrils(CNF) from bleached kraft poplar pulp by using microfluidizer. The properties of CNF were characterized by elemental analysis, scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FT-IR), thermogravimetric analysis and X-ray diffraction analysis. Furthermore, the polymerization degree(DP) of CNF and the energy consumption were calculated. The results showed that DES pretreatment could promote the swelling of pulp fibers, which was beneficial to fibrillation during the microfluidization process. The microfluidization treatment, was performed 15 times. It was found that compared with the energy consumption(4.35×107 kW·h/t) of raw materials without DES pretreatment, the energy consumption(2.44×107 kW·h/t) of raw materials with DES pretreatment decreased by 43.91%. whereas the crystallinity indexes(ICr) of CNF prepared before and after pretreatment were 54% and 44%, respectively. However, DES pretreatment had no obvious effect on the polymerization degree of fiber raw materials. DES pretreatment also reduced the thermal stability of CNF. The increase of homogenization times could promote the fibrillation of fibers, and reduce the crystallinity and polymerization degree of cellulose at the same time. FT-IR analysis showed that choline cations interacted with anionic groups of cellulose fibers through static electricity during DES pretreatment. Elemental analysis showed that nitrogen-containing residues remained in CNFs.

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    Preparation of Multi-doped Activated Carbon Based on Alkali/Thiourea Synergistic Activation
    Qiong WANG, Xuan YANG, Zhenghan CAI, Yandan CHEN, Biao HUANG, Guanfeng LIN
    2021, 41 (4):  77-84.  doi: 10.3969/j.issn.0253-2417.2021.04.011
    Abstract ( 57 )   HTML ( 17 )   PDF (728KB) ( 65 )   Save

    N, P and S multi-doped activated carbon was prepared from sunflower straw by the synergistic activation of KOH and thiourea with its own phosphorus element as phosphorus source, thiourea as nitrogen source and sulfur source. The effect of activation temperature on the adsorption performance of doped activated carbon was discussed. The pore structure and surface chemical properties of doped activated carbon were analyzed by nitrogen adsorption desorption isotherm and X-ray photoelectron spectroscopy(XPS); the electrochemical performance of doped activated carbon as electrode material for supercapacitor was investigate by galvanostatic dharge discharge(GCD) and cyclic voltammetry(CV). The results showed that as the increase of activation temperature, the iodine adsorption value of doped activated carbon increased first and then decreased; when the activation temperature was 900℃, the iodine adsorption value reached the maximum(2 080 mg/g). The synergistic activation of alkali and thiourea was beneficial to enhance the specific surface area and total pore volume of doped activated carbon, the specific surface area and total pore volume of doped activated carbon P, T-900, which was obtained under activation temperature 900℃, were 2 517 m2/g and 1.73 cm3/g, respectively. The doped activated carbon P, T-900 contained nitrogen(N), phosphorus(P) and sulfur(S) elements, and their mass fractions were 1.9%, 0.52% and 2.46% respectively. When the current density was 1 A/g, the specific capacitance of P, T-900 reached 259 F/g in 6 mol/L KOH electrolyte. When the current density was 10 A/g, the specific capacitance of P, T-900 reached 230 F/g, and the initial capacitance retention was as high as 88.8%.

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    Preparation and Performance of a Bio-based Self-healing Material
    Shujie HAO, Meng ZHANG, Lihong HU, Caiying BO, Qi ZHAO, Yonghong ZHOU
    2021, 41 (4):  85-91.  doi: 10.3969/j.issn.0253-2417.2021.04.012
    Abstract ( 78 )   HTML ( 28 )   PDF (4117KB) ( 50 )   Save

    Using rosin as raw material, acrylipimaric acid(APA) was synthesized through Diels-Alder reaction and purified, and then the esterification reaction between APA and epoxidized soybean oil(ESO) were performed to prepare a range of APA and ESO copolymer composite materials(APA-ESO) with different molar ratios of carboxyl and epoxy group. The properties of composite materials were characterized by Fourier transform infrared spectroscopy(FT-IR), thermal gravimetric analysis(TGA), dynamic mechanical analysis, mechanical performance analysis and other methods. Because of the rigid structure of APA, the glass transition temperature(Tg) of the composite material was much higher than room temperature. The Tg of APA-ESO1.25 with the molar ratio of carboxyl and epoxy group 1.25 was the highest(85.4℃) and it showed excellent mechanical properties. The tensile strength of APA-ESO1.00 with the molar ratio of 1.00 reached 18.82 MPa. At the same time, the composite materials exhibited excellent self-repair behavior and reprocessing performance. At 180℃, the self-repair efficiency of APA-ESO0.75 with the molar ratio of 0.75 could reach 90.3% at 5 min, and the self-repair efficiency could reach 92.9% at 30 min. Moreover, the composite material APA-ESO1.00 could be reprocessed by hot pressing, and the mechanical properties after reprocessing could reach 89% of the original sample. In addition, APA-ESO1.00 also had a shape memory effect.

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    Preparation of Activated Carbons from Palm Shell by Response Surface Optimization Design and Its Hydrogen Storage Performance
    Lu LUO, Lingcong LUO, Jianping DENG, Mizi FAN, Guanben DU, Weigang ZHAO
    2021, 41 (4):  92-100.  doi: 10.3969/j.issn.0253-2417.2021.04.013
    Abstract ( 56 )   HTML ( 13 )   PDF (5120KB) ( 54 )   Save

    The palm shell was used as precursor to prepare activated carbons with high specific surface area by KOH activation method. The specific surface area and micropore pore volume were taken as the inspection targets, the influence of different preparation process conditions was explored through single factor experiments and central composite design methods. The hydrogen storage performance of activated carbons prepared under the optimal conditions was studied. The results showed that the activation temperature and the weight ratio of KOH/palm shell char had significant effects on the surface area and micropore volume. The preparation parameters obtained after optimization were 795℃ for activation temperature and 3.64 for impregnation ratio. The average specific surface area and micropore volume of activated carbon prepared under these conditions were 3 491 m2/g and 1.08 cm3/g, respectively. The pore structure analysis results showed that palm shell-based activated carbon was mainly composed of micropores and mesopores, with the maximum microporosity of 89%. Furthermore, it could be seen from the SEM and TEM images that there were a large number of micropores and mesopores distributed in activated carbon. Meanwhile, palm shell activated carbon had excellent hydrogen storage performance. The excess and absolute hydrogen storage capacities were as high as 6.4% and 6.8% under the conditions of -196℃ and 4 MPa, respectively.

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    Effect of Biological Pretreatment on Chemical Components from Cinnamon Twigs and Leaves
    Weixing ZENG, Xian CHENG, Liangwu BI, Shengnan LI, Yuxiang CHEN, Zhendong ZHAO
    2021, 41 (4):  101-110.  doi: 10.3969/j.issn.0253-2417.2021.04.014
    Abstract ( 50 )   HTML ( 7 )   PDF (6436KB) ( 63 )   Save

    The fresh cinnamon twigs and leaves were pretreated by adding water, adding yeast solution, and aging for 45 days, then steam distillation was used to extract the cinnamon oil. GC-MS was used to identify the chemical composition of the cinnamon oil, and finally UHPLC-QTOFMS technology was used to identify the main chemical components of the methanol extract of cinnamon twigs and leaves, and the differences in the main chemical components of the twigs and leaves of cinnamon were analyzed. The results showed that the extraction rate of cinnamon oil after the yeast liquid pretreated the raw twigs and leaves increased by 20.63% when compared with the control group. Biological pretreatment had no significant effect on the composition of cinnamon oil. Using UHPLC-QTOFMS, 34 kinds of compounds were identified from the methanol extracts of the four groups of cinnamon twigs and leaves, including 17 acids, 5 alcohols, 4 glycosides, 3 aldehydes, 3 flavonoids and 2 esters.Through the difference analysis of 34 compounds, it was found that the relative content of volatile components in the methanol extract of cinnamon twigs and leaves increased after yeast liquid pretreatment, and the relative content of non-volatile components decreased, the change trend was consistent with that under the intervention of natural aging.

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    Research Progress of Lignin-based Porous Carbon Materials and Its Applications in Water Purification
    Can JIN, Yunlong LIU, Shuping HUO, Guomin WU, Guifeng LIU, Zhenwu KONG
    2021, 41 (4):  111-123.  doi: 10.3969/j.issn.0253-2417.2021.04.015
    Abstract ( 81 )   HTML ( 17 )   PDF (2324KB) ( 96 )   Save

    Due to the excellent physical and chemical properties such as high specific surface area, large porous volume and adjustable structure morphology, porous carbon materials have been proven to show outstanding adsorption performance for water pollutants. Lignin is a kind of natural and abundant biomass resource. It has the characteristics of high carbon content, low cost, and easy to modification. Thus, it has been regarded as an ideal precursor for replacing traditional fossil resources to prepare porous carbon materials. This review focuses on the preparation methods of lignin-based porous carbon materials and the application research progress in the adsorption and degradation of heavy metal ions, dyes, aromatic compounds, and antibiotics from water. Based on the problems existing in the application of water purification treatment, the development trend of lignin-based porous carbon materials is also prospected.

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    Research Progress in Inhibiting Repolymerization of Lignin Degradation Intermediates
    Mengzhu LI, Ting WANG
    2021, 41 (4):  124-134.  doi: 10.3969/j.issn.0253-2417.2021.04.016
    Abstract ( 65 )   HTML ( 3 )   PDF (894KB) ( 79 )   Save

    The degradation of lignin is freguently accompanied by the repolymerization of its intermediates, which increases the difficulty of further degradation and seriously affects the degradation efficiency of lignin. Therefore, effectively inhibiting the repolymerization of intermediates is the key to improve the degradation efficiency of lignin. Inhibiting repolymerization can achieve the purpose of inhibiting polymerization by changing the reaction path or reaction environment of the lignin degradation system. From the perspective of inhibiting or reducing lignin repolymerization, the thesis summarized three effective methods to increase the degradation rate of lignin by adding inhibitors to the reaction system, shortening the reaction residence time and providing a mild reaction environment.

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    Research Progress of Chemical Constituents and Pharmacological Activity of Elaeagnus Plants
    Hongdan ZHUANG, Fengqiu LI, Ruilong LUO, Liqin WANG
    2021, 41 (4):  135-146.  doi: 10.3969/j.issn.0253-2417.2021.04.017
    Abstract ( 62 )   HTML ( 6 )   PDF (957KB) ( 38 )   Save

    Most plants of Elaeagnus genus were widely used as folk medicines, and their fruits are edible. This review summarized the research progress of the chemical constituents of Elaeagnus plants and their biological activities. The main chemical constituents isolated from Elaeagnus plants, such as flavonoids, triterpenes, sterols, alkaloids, lignans and other compounds, were described in detail. The various activities of the compounds or the extracts such as antioxidant, antibacterial, pesticidal activities, etc, were introduced.Finally, the development potential of Elaeagnus plants in the fields of functional food, health care products and pharmaceuticals were summarized. Further research on their chemical constituents and bioactivities were proposed. And this review could provide reference for the rational use of Elaeagnus plants.

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