Effects of Ethanol Pulping on the Length of Bamboo Cellulose

Vol 14 No. 2Journal of Southest Jiaotong UniversityArticle id:10052429(2006)02017105Effects of Ethanol Pulping on the Length of Bamboo CelluloseTao Yang(陶杨) Liao Junhe(廖俊和) Luo Xuegang(罗学刚)College of Life Science and Engineering, Southest University of Science and Technology, Mianyang 621010, ChinaAbstractOn the conditions of different ethanol concentration, acids and catalyzers, the effects of ethanol pulping on the cellulose lengthof bamboo were studied. The results indicates that ethanol pulping has remarkable effects on the length of cellulose, which is clearlyreduced with adding ethanol and acid. The margin of length of cellulose become smaller with the increase of the catalyzer. When theethanol concentration was 70%, the concentration of acid was 0. 3% and some Naoh was used as catalyzer, the length of cellulosewas the longest.Key words Ethanol; Pulp; Length of cellulose; EffectIntroductioncan be reused by distilling after pulping, and no or alittle black liquor is discharged into the environmentThe length of cellulose, one of the most impor Lignin is a kind of important material in industry, artant properties of raw material in the paper product, the lignin with high purity can be obtained by purifaffects the tensile strength, wearability and breakingying through distilling; thus the problem of pollutionstrength of the paper product. The tensile strength in- from paper industry can be solved. However, in pastcreases with cellulose length, and tearability alsoexperiments, no attempt has been made to study thechanges with the length of cellulose[1-3). In most effects of different conditions on the length of cellu-processes of delignifying, sulfite or alkali is regardedlose. In order to further study the effects of ethandas catalyzer. Under certain conditions, the traditionalprocesses can not only keep the length of cellulose but mum condition of ethanol pulping, bamboo(Neosi-also separate lignin from cellulose to the core, but thenocala musmaterial will be further indischarge of black liquor will bring serious pollu-vestigated in this paper.Katzes improved the technology ALCELLAlcohol Cellulose) by using organic solvents as 1 Experimentalcooking liquor in 1981. Ethanol as cooking liquor forRaw material used in the experiment is bamboolelignifying has been studied in recent years,ItNeosinocala mus affinis), collected from JiangyouSichuan Province, China. Its chemical composition isas follows( mass fraction ) moisture 27. 43%, ashReceived 2005-03-074. 13%, lignin 23. 66% and a-cellulose 65. 48%Foundation item The National High-Tech Development The average length of cellulose is about 2.22 mm863 Program of China(No. 2002AA322050)Yang( 1982-), master candidate. Her re-中国煤化工s7 photomicroscowithGongqing Photo arin bicCNMHElecCorresponding author. Tel. +86-816-6089009; E-mailI polauull, tillia.Ixgxq@my-publicsccninfo.netThe quantity of lignin was measured by acetyJournal of Southwest Jiaotong Universitybromide method 3, and the length of cellulose was ethanol than in water. Fig. 2 shows that when the ethmeasured with the Xsz-HS? photomicroscopanol concentration is 100%-80%, the length of celluA certain quantity of bamboo was mixed withlose shows a general trend of increase with an increasecertain cooking liquor in a 1 000 mL round bottom in ethanol concentration. When ethanol concentrationflask with a stirring system. The temperature was in- is 70%, the length of cellulose reaches its maximumcreased to boiling temperature and kept constant for a value, 1 692 mm, and decreases with a decrease ingiven period of time. After cooking, pulp was filtered ethanol concentration from 70% to 60%and washed with water. The pulp was analyzed and that cellulose is degraded and bond -ruptured if ethanolthe black liquor was distilled. Then the lignin was concentration is over 70%. The residual lignin in celcollected and analyzedlulose can be removed by bleaching, so it follows thatthe optimal ethanol concentration is 70% in this2 Effects of Ethanol ConcentrationexperimentThe effects of ethanol concentration on the quanWhen raw material was 80 g, cooked fortity of lignin and the length of cellulose are shown in 60 min, and the HCl concentration was 3. 33 %, theFigs. 1-4. The catalyzer in Figs. I and 2 is H2 SO4, effect of ethanol concentration is shown in Fig 3. Theand in Figs. 3 and 4 is HCIobtained lignin increases generally with a decrease inWhen raw material was 100 g, cooked for 45the ethanol concentration when the ethanol concen60 min, and the mass concentration of H2 SO. was tration is 70%, the obtained lignin is about 4. 89 g3. 33%, the effect of ethanol concentration on the In Fig 4, when the ethanol concentration is decreasesquantity of lignin is shown in Fig. 1. When the etha- from 100% to 80%, the length of cellulose changesnol concentration is 100%, the obtained lignin is from 1. 465 mm to 1.316 mm. However, when the5. ll g; it is two times that when the ethanol concen- concentration is 70%, the length is 1. 654 mm,reactration is 70%. It can be seen in Fig. I that the quan- hing its maximum. Thus the optimal ethanol concen-ity of obtained lignin is the maximum when the con- tration is 70% in this experimentcentration of ethanol is 100%. decreases with a deThe length of cellulose changes in the same waycrease in ethanol concentration, and increases slightly when HCl or H, SO, is used as catalyzer. The longestwhen ethanol concentration decreases further from cellulose is obtained when the ethanol concentration is0% to 60%, It is because lignin dissolves more in 70%0The length of cellulose byFig. 1 Effect of ethanol concentration on theH中国煤化工centration on thequantity of obtained lignin(H, SO, as catalyzer)CNMHTao Yang et al. Effects of Ethanol pulping on the Length of Bamboo Cellulose100959085807570H2SO,/mLFig 3 Effect of ethanol concentration on theFig 5 Effect of H, so addition on the quan-quantity of obtained lignin(HCl as catalyzer)The length of cellulose byThe length of cellulose bytraditional alkaline pulpingtraditional alkaline pulpingEthanol concentration /Fig 4 Effect of ethanol concentration on theFig 6 Effect of H, SO, addition on the lengthlength of cellulose( HCI as catalyzer)3 Effects of Acid Concentration on of the volumn of H2 S0, addition from about 1% toObtained Components10%. That is because H2 SO, not only catalyzes ligninto separate from cellulose, but also catalyzes celluloseWhen raw material was 100 g, ethanol washydrolyze too. From Fig. 6, the optimal addition of270 mL. water was 30 mL, cooked for 45-60 minH2SO in the experngesthe effect of the H2 SO, addition on the obtained lignin length of cellulose is 1.932 mm. Compared with thatis shown in Fig. 5. The obtained lignin is 3. 35 g and by traditional alkaline pulping, the length of cellulose6.05 g when H2SO, addition is 1 mL and 5 mL,reduces about 11%respectively. HoweverWhen raw material was 100 g, ethanol waswhen H, So, addition is greater than 5 mL. Because 270 mL, and water was 30 mL, cooked for 120 minlignin is a kind of macromolecule composed of benthe effect of the HCl addition on the length of celluzene dimethylmethane, the acid of low concentrationlose is shown in Fig. 7. The length of cellulose re-can catalyze lignin to separate from cellulose. Wherduces with an increase in HCl addition. when 5the acid addition is high, lignin can be hydrolyzed HCl is added into the solvent, the length of celluloseis 1. 487 mm, and when HCl in the solvent is 30 mLnd the quantity of lignin is reducedV凵中国煤化工m, That is becausThe effect of the H2 SO, addition on the length ofHCIcellulose is shown in Fig. 6. The length of cellulose isC N MH GydrolyzeFrom the above discussion we can see that somereduced from 1, 932 mm to 1. 298 mm with an increaseof Southwest Jiaotong Uniuersity4 Comparison of Different CataWhen cooking time was 60 min, ethanol concentration was 80% and raw material was 100effects of different catalyzers on the mass of obtainedlignin and cellulose length are shown in Table 1When the catalyzer is Naoh, the mass of obtained lignin is above 6. 00 g. While the catalyzersare acid and dimethylsufoxide, the mass of obtainedFig. 7 The effect of HCI addition on the lengtlignin is 2. 55-2 78 g, and the longest length of cel-lulose is only 1.516 mm due to degradation by acidacid could catalyze cellulose delignification, but acidFor samples I to 5, when H2 SO, addition iscould also catalyze cellulose to hydrolyze, so the acid 10.0 mL, both the quantities of obtained lignin andconcentration should be low. The interaction between the cellulose length increase with an increase in addithe contradictory factors results in the optimal concen- tion of dimethylsulfoxide. For samples 6 to 10, thetration of ethanol, 90% in mass proportion, and the obtained lignin decreases with an increase in additionoptimal addition of H2 so4, l mL, or 3 %o in volume of NaOH that protects cellulose from degradationproportionTable 1 The effects of different catalyzers on the obtained lignin and cellulose lengthCatalyzer(s)Addition ofObtainedLength oflignin /gcellulose /mm1.0mL10.0mLDimethylsulfoxide2.5mL1.41410,0mL1.439Dimethylsulfoxide5.0mL7.5mL10.0mL10.0mL2.781.516Dimethylsulfoxide11NaOH9.191.838g8.03NaOHRaw materialAlkaline pulping2.180Therefore, in this experiment, when the ethanol 5 Conclusionsconcentration is 80%, the best catalyzer is 10.0 gNaoH, the length of cellulose is l974 mm; though中国煤化工 e length of cellulosethe obtained lignin is 6.9 g at this time, it can be re- reducCNMH Ge concentrations ofethanol and acid if the concentration of ethanol is overmoved by bleachingTao Yang et al./ Efects of Ethanol pulping on the Length of Bamboo Cellulose70%; however, with catalyzer addition, the decre- [6] Qu A, Xu JY, Yu XY, et al. 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