蚕丝脱胶废水中丝胶蛋白的回收技术研究

1SOOCHOWUNIVERSITY硕士学位论文论文题目蚕丝脱胶废水中丝胶蛋白的回收技术研究研究生姓名赵晓晶指导教师姓名张克勤专业名称纺织化学与染整工程研究方向丝胶蛋白的回收论文提交日期2013年3月蚕丝脱胶废水中丝胶蛋白的回收技术研究中文摘要I蚕丝脱胶废水中丝胶蛋白的回收技术研究中文摘要丝胶是蚕丝外层一种水溶性球状蛋白，在化妆品、临床医学、生物材料、保健纺织品后整理等领域都有广泛的应用。但国内大多工厂通常是将含有丝胶蛋白的高浓度有机废水直接排放，这样不仅造成严重的环境污染，而且浪费资源。因此研究脱胶废水中的丝胶回收方法具有重要意义。目前制丝废水中丝胶的回收方法可分为两大类：化学法和物理法。化学法包括酸析法、有机溶剂法、化学混凝法、离子交换回收法；物理法包括离心法、冰冻法和超滤法。本文采用一种全新、环保高效、工艺简单的丝胶回收方法-电场法。其原理为：丝胶具有胶体性质，其等电点为3.8-4.5。而蚕丝精炼一般是在碱性条件下进行，其脱胶废水的pH值均在丝胶的等电点以上，因此废水中丝胶蛋白带负电荷。如对脱胶废水施加以电场，带负电荷的丝胶蛋白分子在电场作用下向阳极发生定向移动、凝聚、沉淀，从而进行回收。本文第三章对电场法回收丝胶工艺进行了研究。利用紫外分光光度法测定脱胶废水中丝胶浓度，并讨论了电极材料、电流密度、反应时间及阴阳极间距等因素对丝胶提取效率的影响。结果表明：阳极采用石墨棒为反应材料，在电流密度为2mA/cm2,反应时间为120min,阴阳极间距为3cm时，丝胶的提取效率可达到60%左右。本文第四章对加电场前的丝胶溶液和电场法提取出的丝胶沉淀，分别进行真空冷冻干燥，得到丝胶粉末。红外光谱（FTIR）、圆二色（CD）、X射线衍射（XRD）的测定结果表明：加电场后，丝胶的二级结构有无规卷曲向β-折叠转变的趋势，结晶度提高；通过性质分析可知：加电场后丝胶的分子量增大，疏水性氨基酸含量增加，溶解率有所下降。关键词：丝胶蛋白；丝胶回收；电场法；环保高效；凝聚作者：赵晓晶指导教师：张克勤AbstractSericinrecoveryfromalkalinedegummingwastewaterbyelectrochemicaltechnologyIISericinrecoveryfromalkalinedegummingwastewaterbyelectrochemicaltechnologyAbstractSericin,awater-solubleglobularproteinwrappedthesilkstrands,hasthewideapplicationsintheareaofthecosmetic,clinicalmedicine,biomaterialsandfinishingonthehealthcaretextile.Buttheorganicwastewatercontainingthehighlyconcentratedsericinisusuallydischargedintotheriverbymostofdomesticfactory.Andthus,itwillbecometheseriouspollutiontotheecologicalsystem.Therefore,itisverycriticaltodevelopthetechniquestorecoverthesericinfromthesilkdegummingwastewater.Themainmethodsofsericinrecoveryfromthewastewaterbasedonthechemicalandphysicalprinciplesaresummarized,whichincludetheacidicprecipitation,organicsolventprecipitation,chemicalcoagulation,ionexchangemethod,centrifugation,freeze-methodandultrafiltrationmethod.Anovel,environmentalandsimplemethodbasedonourcurrentresearchisalsoproposedwhichnamedelectrochemicalmethod.Theprincipleofrecyclingsericinbythismethodis:Sericinproteinhasthenatureofthecolloidalparticleswiththeisoelectricpointabout3.8-4.5.Degummingofsilkfiberisusuallyinalkalinecondition.ThepHofthedegummingwastewaterisabovethePI,sothesericinproteininthewastewaterchargesnegative.Accordingtotheelectricalpropertiesofsericinprotein,weapplytheelectricfieldtothewastewatercontainingsericin.Asaresult,thesericinproteinwithchargeswillmovedirectionallyandgathergradually.Theexperimentalstudyonrecyclingsericinbyelectricalmethodwasshowninchapter3.UV-Visspectrophotometerwasusedtoestablishthelinearrelationshipbetweenabsorbencyofsolutionanditsconcentration.Itdiscussedtheinfluenceoftheelectrodematerials,currentdensity,reactiontimeandelectrodespacingontheextractionefficiencyofsericin.Theresultsshowedthattheanodegraphiterodsasreactionmaterials,inthecurrentdensityof2mA/cm2,thereactiontimeof120min,electrodespacingin3cm,sericinextractedefficiencycanreachabout60%.Inchapter4,theuntreatedsericinsolutionandsericinprecipitationextractedbyelectricalmethodwereprocessedwithvacuumfreezedrying.ThesericinsecondarySericinrecoveryfromalkalinedegummingwastewaterbyelectrochemicaltechnologyAbstractIIIchangesafterapplyingtotheelectricfieldwerediscussedbyinfraredspectroscopy(FTIR),circulardichroism(CD),X-raydiffraction(XRD)measurement.Theanalysisshowedthatthesecondarystructureofsericinchangedfromrandomcoiltoβ-sheettrendafterapplyingtheelectricfieldtothesericinsolution.Thesericinpowdersobtainedfromthismethodhavebeencharacterizedintermsofdissolutionratio,molecularweightdistributionandaminoacidanalysis.Theresultsshowedthatthemolecularincreased,thecontentofhydrophobicaminoacidincreasedandthedissolutionratedecreased.Keywords:sericinprotein;sericinrecovery;electricfieldtreatment;environmentalandhighefficiency;condenseWrittenby:ZhaoxiaojingSupervisedby:ZhangKeqin目录第一章绪论..........................................................................................................11.1序言....................................................................................................................11.2丝胶蛋白的结构...............................................................................................21.3丝胶蛋白的分子量...........................................................................................31.4丝胶蛋白的理化性质........................................................................................31.4.1丝胶蛋白的胶体性质..........................................................................41.4.2丝胶蛋白的两性性质和等电点............................................................41.4.3丝胶蛋白的变性..................................................................................41.5丝胶蛋白的应用领域.........................................................................................51.5.1在化妆品中的应用..............................................................................51.5.2在临床医学中的应用..........................................................................51.5.3在生物材料中的应用..........................................................................61.5.4在保健纺织品后整理中的应用............................................................71.6丝胶蛋白的回收技术....................................................................