改性木薯淀粉的制备及其对焦化废水絮凝效果研究_官挺

宝鸡文理学院学报(自然科学版),第29卷,第4期,第24-28页,2009年12月JournalofBaojiUniversityofArtsandSciences(NaturalScience),Vol.29,No.4,pp.24-28,Dec.2009改性木薯淀粉的制备及其对焦化废水絮凝效果研究＊官挺,董国文,王仁章,蓝华远(三明学院化学与生物工程系,福建三明365004)摘要:目的合成可生物降解的炼焦废水絮凝剂-羧甲基淀粉(CMS),并对其絮凝效果进行研究。方法用ClCH2COOH对木薯淀粉(St)进行改性,采用乙醇作为溶剂,分两步合成CMS。结果实验结果表明,改性木薯淀粉较佳制备条件:nSt(M=162)∶nClCH2COOH=1∶1,nNaOH∶n(ClCH2COOH)=2.5∶1,碱化温度35℃,醚化温度50℃。获得改性木薯淀粉处理焦化废水工艺条件,在淀粉取代度为0.37,投入量为50g/L废水,反应温度为40℃,搅拌时间为10min,静置时间为30min时,处理效果最好,对焦化废水浊度去除率高达79.5%以上。结论改性木薯淀粉对焦化废水浊度有明显降低效果,但用量大(50kg/m3废水)和对于废水中的CODCr去除率低依然需要深入研究。关键词:羧甲基淀粉;取代度;木薯;絮凝效果中图分类号:O636.12;O631.32文献标志码:A文章编号:1007-1261(2009)04-0024-05StudyonthepreparationofmodifiedcassavastarchanditsflocculationeffectoncokingwastewaterGUANTing,DONGGuo-wen,WANGRen-zhang,LANHua-yuan(DepartmentofChemicalandBiologicalEngineering,SanmingCollege,Sanming365004,Fujian,China)Abstract:AimToprepareanon-toxicandbiodegradableflocculant-carboxymethylstarch(CMS)-totreatthecokingwastewaterandanalyzeitsflocculationeffect.MethodsChloroaceticacidisusedtomodifycassavastarch(St),thencarboxymethylstarch(CMS)issynthesizedintwostepsbyusingethanolassolvent.ResultsTheexperimentalresultsshowedthattheoptimumconditionsofCMSsynthesisareasfollows:nSt∶nClCH2COOH=1∶1,nNaOH:nClCH2COOH=2.5∶1,alkalizationtempera-ture35℃,etherificationtemperature50℃,thedegreeofsubstitutionofmodifiedcassavastarchwas0.37.Theprocessofcokingwastewatertreatmentwasalsoinvestigated,thebestresultsofover79.5%turbidityremovalratewasobtainedwiththemodifiedcassavastarch(50g/Lwastewater)atreactiontemperature40℃,stirringtime10minandthenstandingtime30min.ConclusionAlthoughmodifiedcassavastarchhastheobservablepropertiesofreducingtheturbidityandCODCrofthecokingwastewater,itslargeconsumption(50kg/m3wastewater)andlessremovalrateofCODCrwillrequirefurtherstudy.Keywords:carboxymethylstarch;degreeofsubstitution(DS);cassavastarch;flocculation木薯羧甲基淀粉(CMS)是一种以淀粉为原料,经醚化反应制成的变性淀粉。它可部分地替代羧甲基纤维素(CMC)应用,CMS的生产成本及销售价格远低于CMC,CMS正逐渐取代CMC在市场中的地位,具有广阔的发展前景[1,2]。CMS在食品工业中作为品质改良剂,在造纸工业中用作粘合剂,在石油工业中用作保水剂