Table of Content

30 September 2004, Volume 24 Issue 3 Previous Issue    Next Issue

研究报告

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EFFECTS OF NITROGEN SOURCES ON THE BIOSYNTHESIS OFXYLANASE AND CELLULASE BY TRICHODERMA REESEI YONG Qiang;LI Shu-yan;CHEN Mu;XU Yong;YU Shi-yuan 2004, 24 (3):  7-11.  Abstract ( 653 )   PDF (752KB) ( 749 )   Save Effects of nitrogen sources and C/N on the biosynthesis of xylanase and cellulase by Trichoderma reesei were investigated.Peptone is the best nitrogen source for xylanase and cellulase production among the nitrogen sources which have been studied.The highest xylanase activity was 93.3 IU/mL,when nitrogen from ammonium sulfate to that from urea was 1:3,and when this value was changed to 1:1,the highest filter paper activity and CMCase activity were obtained,which were 0.263 FPIU/mL and 0.026 IU/mL,respectively.The best ratio of C/N for the biosynthesis of xylanase and cellulases was different.It was 8.0 for the former and 6.0 for the latter.In these cases,xylanase activity and cellulase activity were 95.1 IU/mL and 0.310 FPIU/mL,respectively. Related Articles | Metrics

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STUDY ON GRAFT-COPOLYMERIZATION OF CRUDE LIGNOSULFONATES WITH ACRYLIC MONOMERS LI Jian-fa;SONG Zhan-qian;SHANG Shi-bin;LU Jin-hong 2004, 24 (3):  1-6.  Abstract ( 667 )   PDF (636KB) ( 771 )   Save Graft copolymerization of crude lignosulfonates with acrylic monomers was investigated,its mechanism was reviewed,and the occurrence of polymerization was confirmed by IR determination.Differing from pure lignosulfo-nates,graft copolymerization of crude lignosulfonates with acrylic monomers could be initiated solely by hydroperoxide at 1.5%-2.0%(mass ratio) of dry lignosulfonates.With sufficient initiator in the reaction solution,the influence of reaction temperature and time on viscosity of products was not apparent.Viscosity of final products was increased following the increase of monomers dosage.At the same dosage, products modified with acrylamide(AM) had higher viscosity than those with acrylic acid(AA),because amide groups on AM polymers is less hydrophilic than carboxylic groups on AA polymers. Related Articles | Metrics

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STUDY ON ELECTROCHEMICAL DEGRADATION OF DESALTING EFFLUENT FROM XYLAN ULTRAFILTRATION YANG Fu-guo;XU Yong;SONG Xiang-yang 2004, 24 (3):  12-14.  Abstract ( 611 )   PDF (371KB) ( 512 )   Save Electrochemical method treatment of desalting effluent from xylan ultrafiltration was studied with RuO2-Ti anode and Ti cathode.The result showed:electrochemical treatment of desalting effluent from xylan ultrafiltration can reduce chroma,CODCr and BOD5 of the wastewater from 1400,5160 mg/L and 1820 mg/L to 50,150 mg/L and 100 mg/L respectively,which meet the requirements of the discharge standard.The mechanism of electrochemical oxidation was also explored from its UV spectra. Related Articles | Metrics

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STUDY ON DISTILLATION OF OLEORESIN BY CIRCULATING GAS METHOD WITH CARBON DIOXIDE OR NITROGEN CHEN Xiao-peng;WANG Lin-lin;ZHU Yuan-jiao;WEI Xiao-jie 2004, 24 (3):  15-20.  Abstract ( 598 )   PDF (788KB) ( 966 )   Save Distillation of oleoresin was studied,using Claisen flask as still and CO2 or N2 as circulating gas.Factors such as flow capacity of circulating gas,distillation pressure,end distillation temperature,temperature of circulating gas,and kinds of gas which influence the distillation of oleoresin were investigated.The results showed that optimum technological conditions of distillation of pine gum for producing 1 kg rosin were as follows:flow rate of CO2(0.140-0.160 m3/h),distillation pressure 12.67 kPa,end temperature of distillation 185-190℃.The effects of temperature and kinds of circulating gas on distillation of oleoresin were insignificant.Since boiling point and content of distillate components are different,operation sequences of flow rate of CO2 at(0.100-0.160 m3/h) and distillation temperature at 80-185℃ were preferable.According to the experimental results,a technological flow diagram has been designed.Since no phase change occurs during circulating gas distillation,heat for phase change of overheated steam in traditional process has been saved.Compared with direct steam method,the consumptions of energy and cooling water by this method were decreased by 1.663-2.034 GJ and 7.986-9.762 m3 respectively.Separator for oil from water,filter for salt and large boiler for producing overheated steam were not required to be built.Water was not contaminated in products manufactured by this method.The rosin shows no crystallanity,turpentine is transparent without turbidity,and no wastes are produced. Related Articles | Metrics

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STUDY ON PREPARATION OF ACTIVATED CARBON FOR REFINING WATER FROM PETROLEUM COKE LIU Jun-li;GU Ke-long;HAN Song;TAN Jun-li 2004, 24 (3):  21-25.  Abstract ( 595 )   PDF (730KB) ( 1091 )   Save Activated carbon from petroleum coke was prepared by the method of water-steam activation with the addition of 3%-5%(mass part) acid activating agent.Broken granular activated carbon has the specifications of iodine value 521 mg/g,carbon tetrachloride(CCl4) adsorption 22%,and shaped cylindrical activated carbon has the specifications of iodine value 800-900 mg/g,methylene blue adsorption 120 mg/g,CCl4 adsorption 38%-46%,phenol adsorption 180-260 mg/g,ash 3%-5%,hardness 91%-95%.Results showed that acid activating agent is beneficial to create the micropore of activated carbon and improves the quality of activated carbon.Based on laboratory results,enlarged experiment in factory was carried out and the obtained products were similar to the sample acquired in the laboratory.Their performances both reached or exceeded national standards of wood-based and coal-based activated carbon for refining water. Related Articles | Metrics

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STUDY ON α-PINENE ISOMERIZATION CATALYZEDBY MoO3/ZrO2 SOLID SUPERACID LUO Jin-yue;ZHANG Xiao-ping;AN Xin-nan 2004, 24 (3):  26-30.  Abstract ( 507 )   PDF (1187KB) ( 676 )   Save Isomerization of α-pinene catalyzed by MoO3/ZrO2 solid superacid was studied.This kind of catalysts prepared by(NH4)6Mo7O24·4H2O has high activity and good selectivity.From experiments,it was found that catalysts calcination,dosage,reaction time,reaction temperature,etc.,have significant effects on catalysts activity and insigni-ficant effects on the selectivity of camphene.The optimum conditions for α-pinene isomerization were as follows:catalysts calcination temperature 800℃ for 3 h,mass ratio of solid superacids to α-pinene 0.03,isomerization temperature 120℃±2℃ for 8 h.Under these conditions,convertion of α-pinene is 93.5%,and selectivity of camphene is 60.7%. Related Articles | Metrics

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STUDIES ON SYNTHESIS OF ROSINOYL DIETHANOLAMINE ACIDAMIDE BY PROTECTING HYDROXYL GROUP AND ITS SURFACTANT PROPERTIES FENG Guang-zhu;LI Xi-hong;LU Kui;LI He-ping 2004, 24 (3):  31-35.  Abstract ( 702 )   PDF (909KB) ( 968 )   Save Rosin acid methyl ester(RAME) was prepared from rosin acid and carbinol at yield 95.50%.Rosinoyl diethanolamine acidamide(RDEA) was then synthesized from rosin acid methyl ester with tetrahydropyrane-2-yl ether of diethanolamine,in which the hydroxyl groups of diethanolamine were pre-protected by tetrahydrofuran.Quadric orthogonal experiment result shows that optimum synthetic conditions were as follows:molar ratio of rosin acid methyl ester to tetrahydropyrane-2-yl ether of diethanolamine 1:1.6,reaction temperature 93℃,reaction time 4.4 h,sodium ethoxide as catalyst 2% of tetrahydropyrane-2-yl ether of diethanolamine,yield of the product 93.87%.In addition,surfactant properties of rosinoyl diethanolamine acidamide were also determined,which has good capabilities of foaming and emulsification as those of lauryl sodium sulfate(K12). Related Articles | Metrics

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STUDY ON FIRE-RETARDATION MECHANISM OF FIRE RETARDANT FRW BY THERMOANALYSIS WANG Qing-wen;LI Jian 2004, 24 (3):  37-41.  Abstract ( 654 )   PDF (725KB) ( 963 )   Save The thermo-decomposition of fire retardant FRW and its main components,namely boric acid and guanylurea phosphate(GUP),and the pyrolysis of basswood treated with boric acid(BZ),basswood treated with GUP(GZ),basswood treated with FRW(FZ) and untreated basswood(UZ) were analyzed by thermogravimetry(TG and DTG) and differential thermoanalysis(DTA) respectively.The TG and DTG results revealed that when fire retardant FRW was heated to its decomposition temperature its components decomposed independently,thus boric acid decomposed to HBO2(at about 95℃),the later in turn to B2O3(at about 160℃).GUP decomposed to guanidine polyphosphate GPP(at about 180℃),then to ammonium polyphosphate APP(at about 285℃),and in turn to polyphosphoric acid PPA(at about 385℃).The pyrolysis process of basswood was changed by the treatment of FRW or its components.It was discovered that BZ lost weight at quite lower temperature(165℃) than UZ did,and this may be attributed to the catalytic effect(catalytic dehydration) of boric acid on the pyrolysis of basswood to form char.Compared to the temperature of maximum weight loss rate of UZ(375℃),the corresponding temperature of GZ decreased to 314℃,and the weight loss rate of GZ decreased considerably,but charring increased.The weight loss rate of FZ was lower than the value of BZ or GZ.The TG curve of FZ,was not equal to the sum of GZ and BZ,intercrossed with the other two curves,which indicated the synergistic effect of fire retardants between GUP and boric acid.The DTA results (supported) the above results.Besides,a exothermic peak was recorded on the DTA curve of BZ at about 425℃,which may be explained by the catalytic effect of B2O3 on the structural change(from aliphatic to aromatic) of the pyrolysis products of BZ at high temperature. Related Articles | Metrics

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STUDIES ON LIQUEFACTION OF BAMBOO AND PROPERTIES OF LIQUEFIED-BAMBOO ADHESIVES FU Shen-yuan;MA Ling-fei;LI Wen-zhu 2004, 24 (3):  42-46.  Abstract ( 690 )   PDF (993KB) ( 863 )   Save The liquefaction of bamboo was studied,which involved mass ratio of phenol to bamboo,amount of catalyst,the effect of temperature,etc..The study showed that complete liquefaction could be accomplished at phenol/bamboo dosage(mass ratio) 2-1:1,catalysts of HCl or BF3 5%,temperature 115℃.By reacting liquefied-bamboo(BL) with formaldehyde,a liquefied-bamboo phenol formaldehyde resin adhesive(BLF) of exterior grade could be prepared at phenol/formaldehyde(molar ratio) 1:1.6-2.0.The curing behaviour of BLF resins studied by TG-DSC and IR (analysis) showed that BLF adhesive had lower curing temperature and similar characteristic peaks in IR spectra as PF adhesives. Related Articles | Metrics

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STUDY ON ISOLATION OF CHLOROGENIC ACID AND FLAVONOIDS IN EUCOMMIA ULMOIDES LEAF BY MACROPOROUS RESIN MA Xi-han;WANG Dong-mei;SU Yin-quan 2004, 24 (3):  47-51.  Abstract ( 610 )   PDF (659KB) ( 996 )   Save A specific macroporous resin,XDA-5 was selected from 10 different resins to adsorb and isolate chlorogenic acid and flavonoids from the leaves of Eucommia ulmoides through investigating the factors such as the capability of static adsorption and desorption.Thereafter,a methodological study was carried out on this resin.The following results were obtained.1)The favorable technological parameters for the isolation are:pH value 2-3 of the liquid extract to be isolated,static adsorption time 8 h,eluant for chlorogenic acid 10%-15% ethanol,for flavonoids 50%-70% (ethanol),elution rate 8% of the volume of the adsorbent per minute;2)The eluent rich in chlorogenic acid is concentrated by vacuum distillation at a yield of solid extracts 4.85%,content of chlorogenic acid in solid extract 36.65%,yield of chlorogenic acid 1.78%;3)The eluent rich in flavonoids is concentrated at a yield of solid extracts 4.98%,content of flavonoids 28.34%. Related Articles | Metrics

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LIQUEFACTION OF BAGASSE IN TETRALIN GUO Gui-quan;WANG Hong-juan;CHEN Fan-geng 2004, 24 (3):  52-56.  Abstract ( 651 )   PDF (774KB) ( 922 )   Save The liquefaction of bagasse in tetralin with and without iron-based catalyst is studied in this paper.The residue rate and oil yield are approximately 18% and 30% respectively at 400℃ whether the reaction are conducted for 5 min or 1 h.The residue rate is doubled when reaction time varies from 5 min to 1 h at 500℃ while oil yield was reduced.At 400℃ oil yield is enhanced and residue rate does not change when FeOOH and Fe2S3 are impregnated into bagasse.However,the catalysts do not enhance oil yield at 500℃.The reason why iron-based catalyst enhanced oil yield is that iron-based catalyst promotes the transfer of hydrogen free radicals from tetralin onto the free radicals from thermodecomposition of free radical fragments from condensation,which results in the formation of stable compounds that are not easily decomposed or gasified.It is concluded that bagasse is dissolved mainly by tetralin at low temperature and that the decomposition of bagasse is followed by the dissolution of fragments at high temperature. Related Articles | Metrics

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STUDY ON FERMENTATION CONDITIONS FOR PRODUCING ALKALINE CELLULASE BY BACILLUS SP. AC-2 STRAIN SHU Qin;XIA Li-ming 2004, 24 (3):  57-60.  Abstract ( 673 )   PDF (725KB) ( 661 )   Save Fermentation conditions for producing alkaline cellulase by Bacillus sp.AC-2 were studied in shaking flasks strain.Results showed that the suitable inoculum age was 24 h.Optimal culture temperature and initial pH value were 37℃ and 10.5,respectively.The maximal alkaline cellulase activity reached 76.04 U/mL under the optimal conditions with 1% starch and 2% bean cake as carbon and nitrogen source,respectively.The enzyme preparations were stable between pH value 6.0 to 10.0 and below 70℃.The reaction catalyzed by alkaline cellulase at pH value 9.5 showed an optimum temperature of 60℃.This enzyme would have a good potential application in textile biofinishing and pulp-deinking. Related Articles | Metrics

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STUDIES ON PYROLYSIS OF WOODEN MATERIAL AND STRUCTURE OF THE OBTAINED ACTIVATED CARBON DAI Wei-di;TAO Yuan-bo;ZHANG Yan-ping;JIANG Jian-chun 2004, 24 (3):  61-64.  Abstract ( 573 )   PDF (813KB) ( 969 )   Save Pyrolysis of coconut shell was carried out in this study.Mechanism of coconut shell pyrolysis was studied using thermogravimetric analysis method.Similar to common wooden materials,coconut shell is also composed of semi-cellulose,cellulose and lignin.In coconut shell,semi-cellulose decomposes at 200-260℃,cellulose at 260-295℃ and lignin at 295-320℃.The pore structure parameters of coconut shell activated carbon are studied.At carbonizing temperature between 425℃ and 720℃,the micropore volume is between 0.124-0.222 mL/g.Surface of the activated carbon is also observed by scanning electron microscopy(SEM).During thermogravimetric analysis,the cell wall of coconut shell disassembles to form macropore at μm level while its cellulose structure was retained.The main trace elements in coconut shell carbon,such as Al,Ba,Fe,Mg,Ca,Si were measured by ICP. Related Articles | Metrics

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DESORPTION OF SO2-LOADED ACTIVATED CARBON BY MICROWAVE IRRADIATION NING Ping;CHEN Yu-bao;PENG Jin-hui;ZHANG Shi-min;CHEN Hai-yan 2004, 24 (3):  65-68.  Abstract ( 566 )   PDF (565KB) ( 888 )   Save In order to produce high concentration SO2 product gas,the method of microwave desorption of SO2-loaded activated carbon was studied.The experiments on influences of operating conditions on SO2 desorption such as the microwave power,gas-loaded quantum,activated carbon quantum,regeneration time and times of activated carbon were carried out.The optimal operating conditions were got.Under the conditions of microwave power 700 W,feed gas flow rate 0.3 L/min,irradiation time 3 min,concentration of SO2 product gas can reach 90% with 8 g activated carbon. Related Articles | Metrics

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CONSTITUENT ANALYSIS OF UNSATURATED FATTY ACID AND TECHNOLOGY OF EXTRACTION FROM ACTINIDIC CHINENSIS PLANCH SEEDS WANG Jin-qiu;ZHOU Wei-chun;SONG Qiang;SONG Jin-biao 2004, 24 (3):  69-72.  Abstract ( 593 )   PDF (622KB) ( 734 )   Save Unsaturated fatty acid was obtained from Antinidia chinensis Planch seeds.The contents of each fatty acid component in product are as follows:palmitic acid 4.82%,stearic acid 3.72%,oleic acid 13.11%,lindeic acid 10.36%,linolenic acid 64.99%,arachidonic acid 2.03%,respectively.The optimum conditions of extraction by orthogonal tests are:temperature 60℃,time 30 min,ratio of liquor to material:petroleum ether(mL):seeds(g) (4.0:1.0),extract 3 times.Under such conditions,the yield of the extraction is 29.70%. Related Articles | Metrics

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STUDY ON BIOACTIVE CONSTITUENTS IN ALCOHOLIC FRACTIONS OF MONTAN RESINS FROM BROWN COAL WAXES LI Bao-cai;ZHANG Hui-fen;BI Li;XIN Xiao-yan;BU Yi-sun 2004, 24 (3):  73-77.  Abstract ( 650 )   PDF (934KB) ( 711 )   Save To explore the possibilities of utilizing montan resins as a Chinese medicine,the alcoholic fractions of montan resins isolated from brown coal waxes which were extracted from Liaohu,Xundian(Yunnan) and Shulan(Jilin) brown coals were studied by gas chromatography-spectrometry.The experimental results show that alcoholic fractions in montan resins mainly consist of normal long chain alcohols of carbon number C15-C30(C22,C24,C26 as major constituents for the series),long chain ketones of carbon number C18,C23,C25,C27,C29 and 15-hentriacotanone,sterols,pentacyclic triterpene alcohols and pentacyclic triterpene ketones.Alcoholic fractions from Xundian and Liaohu contain 24-methyl-5β(H)-cholestane-3β-ol(C28H50O,MW 402), 24-ethyl-cholest-5,22-dien-3β-ol(C29H48O,MW 412),24-ethyl-5α(H)-cholestane-3β-ol(C29H52O,MW 416), 23,24-dimethyl-cholest-5-en-3β-ol(C29H50O,MW 414),C29-5β(H),3β(OH)-sterol(C29H52O,MW 416), 24-isopropyl-cholest-5,24(28)E-dien-3β-ol(C30H50O,MW 426),etc.,at a relatively abundant amount.However sterols are almost absent or in very trace amount in Shulan montan resin.Based on their chemical constituents Xundian and Liaohu brown coal resins would be probably a resource as Chinese medicine. Related Articles | Metrics

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STUDIES ON SYNTHESES AND PROPERTIES OF WATERBORNE POLYURETHANE RESIN FROM CASTOR OIL QU Jin-qing;CHEN Huan-qin 2004, 24 (3):  78-82.  Abstract ( 865 )   PDF (867KB) ( 2405 )   Save Waterborne polyurethane(WPU) was prepared by the reaction of castor oil(C.O.) with polyether glycol(N 210),dimethoxypropionic acid(DMPA) and toluene diisocyanate(TDI).The effects of mass ratio of castor oil,N 210,DMPA content,molar ratios of NCO to OH and NH2/NCO on the properties were investigated.The structure of WPU was characterized by FT-IR.It was found that mechanical properties and water resistance of WPU coating film were increased with addition of castor oil.At 1:1-2 mass ratio of castor oil to N 210,1.6 molar ratio of NCO/OH,(5.5%) DMPA content and 0.50 molar ratio of NH2/NCO, the castor oil waterborne polyurethane has excellent film-forming property,high hardness,good resistances to water and petrol,and excellent adhesion to base materials. Related Articles | Metrics

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PREPARATION AND CHARACTERIZATION OF CROSSLINKED CARBOXYMETHYL-KONJAC-GLUCOMANNAN GRANULES LUO Li-xin;FENG Chang-gen 2004, 24 (3):  83-86.  Abstract ( 518 )   PDF (715KB) ( 818 )   Save Carboxymethyl-konjac-glucomannan granules(CMKGG) are prepared from konjac-glucomannan granules(KGG) and chloroacetic acid in alcohol solution.The crosslinked carboxymethyl-konjac-glucomannan granules((CCMKGG)) is then prepared.Factors influencing the reaction are discussed.CCMKGG may be used as a new adsorbent.From orthogonal experiments,the optimum conditions are:NaOH 20% of KGG,chloroacetic acid 10 times of KGG,temperature 55℃,reacting time 8 h with 30% alcohol solution,to obtain the product with good exchange capa-city.The results of IR,optical microscopy and SEM measurements show that CCMKGG are alveolate particles of homogeneous granularity,with cation interchange capacity 0.9538 mmol/g.CCMKGG are insoluble in water,and stable in acid and alkali. Related Articles | Metrics

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STUDY ON ENZYMATIC HYDROLYSIS OF CELLULOSE FROM SECONDARY FIBERS TO GLUCOSE HANG Zhi-xi 2004, 24 (3):  87-89.  Abstract ( 522 )   PDF (390KB) ( 1118 )   Save After de-inking and washing-off,the waste paper is called secondary fiber.Lignin and hemicellulose are removed from secondary fiber to obtain cellulose,which is hydrolyzed by cellulase to obtain glucose.The temperature,pH value,dosage of enzyme and time are experimented by measuring the content of glucose to find out the optimal condition of enzymatic hydrolysis:temperature 45℃,pH value 4.8,dosage 8 IU/g(based on dry material).The product yield may exceed 60%. Related Articles | Metrics

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STUDY ON PREPARATION METHOD OF POLYSACCHARIDES FROM JUJUBE(ZIZIPHUS JUJUBA MILL.)RESIDUE YANG Yun;TIAN Run-tao;FENG Wei-sheng;MENG Jiang;MIAO Ming-san 2004, 24 (3):  91-94.  Abstract ( 458 )   PDF (745KB) ( 847 )   Save Method on preparation of polysaccharides from jujube(Ziziphus jujuba MILL.)fruit residue after extraction of jujube essence had been carried out. The enzyme method was optimized by orthogonal test with polysaccharides content and yield ratio as index.The purification process was examined with the rate of decolouration and desalination as index.The optimum conditions are: 3% of trypsin, 65℃, pH value 7 and extracted 1.5 h,then adding 2.0% of papain at 55℃ and extracted 1 h.The extracted solution was then decolorized through macro-reticular adsorption resin column followed by cation and anion exchange resin columns alternatively for desalting to obtain the purified polysaccharides. Related Articles | Metrics

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REVIEW ON FAST PYROLYSIS OF BIOMASS FOR BIO-OIL LIU Shou-xin;ZHANG Shi-run 2004, 24 (3):  95-101.  Abstract ( 1047 )   PDF (770KB) ( 2182 )   Save Fast pyrolysis of biomass for bio-oil is a kind of new technology of energy conversion which attracts growing research rapidly.Bio-oil can replace traditional mineral fuels or be used as raw material to produce special chemicals such as slow-releasing fertilizers.In the present article,the principle,characteristics,reactors,and special requirements for the fast pyrolysis of biomass were reviewed.The potential application fields of bio-oil were summarized.A practical study showed the application of this technology on waste wood and indicated the potential application of this approach to control contaminations. Related Articles | Metrics

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PROGRESS IN STUDIES ON PREPARATION AND PROPERTIES OF CELLULOSE-BASED ADSORBENTS QU Rong-jun;SUN Xiang-rong;WANG Chun-hua;SUN Chang-mei;CHENG Guo-xiang; 2004, 24 (3):  102-106.  Abstract ( 551 )   PDF (573KB) ( 1625 )   Save As one of the most abundant renewable natural polymers on earth,cellulose is readily available and inexpensive.Also it can be biodegraded easily without pollution on environment.Many investigators have done works on the development and utilization of cellulose for a long time.In this paper,the preparation of adsorbents based on cellulose is reviewed.The structures and properties of the modified cellulose as metal-ion adsorbents and special adsorbents are introduced.The long-term potential development of cellulose-based adsorbents is mentioned. Related Articles | Metrics

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RESEARCH PROGRESS ON NATURAL RESOURCES AND APPLICATION OF THE BIOACTIVE SUBSTANCE——SQUALENE ZHAO Zhen-dong;SUN Zhen 2004, 24 (3):  107-112.  Abstract ( 997 )   PDF (826KB) ( 3573 )   Save The sources and applications of the bioactive substance squalen that widely exists in animals and plants are reviewed.According to the citations,the most abundant sources of squalene in animals are deep-sea fishes,especially sharks,in which the highest content of squalene is approached to 69% based on liver oil.Amaranth seed oil,olive oil and palm oil are the major plant sources of squalene.The content of squalene is 5 %-8% in amaranth seed oil,and the highest content is 1.16% in olive oil.Because of the strong bioactivity,squalene is widely used in medical care fields and in cosmetics.Squalene is easy to oxidize,so it must be kept with suitable antioxidant during storage. Related Articles | Metrics

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PROGRESS AND DEVELOPMENT TREND OF RESEARCHES ON PLANT ANTIOXIDANTS ZHENG De-yong;AN Xin-nan 2004, 24 (3):  113-118.  Abstract ( 597 )   PDF (566KB) ( 1644 )   Save Plant antioxidants and their related active compounds can be divided into the following categories:flavonoids,plant polyphenols,phenolic acids,vitamins,polysaccharides,enzymes,proteins and amino acids.Antioxidants may exert their effects on biological systems through different mechanisms including electron donation,metal ion chelation,synergistic effect of antioxidants or by genes expression regulation.The applications of antioxidants as additives are widespread in the fields of food,beverages,medicines and cosmetics.It is proposed that the following studies should be carried out more intensively:selection of raw materials,innovation of extraction and separation,mechanism of synergistic effects of antioxidants,relationship between compound structures and antioxidant activities. Related Articles | Metrics