纤维素酶系组成对废新闻纸脱墨的影响

采用不同F/C比值的纤维素酶对废新闻纸进行脱墨,以探讨不同酶系组成对脱墨浆白度、尘埃度、强度的影响。研究结果表明,脱墨浆白度随着F/C比值的增加而提高;尘埃度和强度则得到相反的结果。对酶处理液中还原糖含量的分析和脱墨浆结晶度的测定则证明了脱墨所采用的纤维素酶系组成中所含外切酶和纤维二糖酶越多,对脱墨浆白度及纤维强度的影响就越大。     

纤维素／半纤维素酶配合漆酶预处理马尾松未漂磨石磨木浆的研究

分别用半纤维素酶Pulpzyme HC、纤维素酶Novozym 476对马尾松未漂磨石磨木浆(GP)进行预处理，然后再进行NS51003漆酶／介体系统生物酶处理及后续的H2O2漂白，并对酶处理浆在H2O2漂白前后白度和强度性能进行测定。研究结果表明，利用半纤维素酶Pulpzyme HC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理，可有效提高漆酶NS51003处理马尾松未漂GP的效率，更加有效的提高纸浆的白度及强度性能，而且适当的预处理可使纸浆具有更好的可漂性，从而使H2O2漂白后的酶处理浆具有更高的白度和更好的强度性能。     

纤维素/半纤维素酶配合漆酶预处理马尾松未漂磨石磨木浆的研究

分别用半纤维素酶PulpzymeHC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理,然后再进行NS51003漆酶/介体系统生物酶处理及后续的H2O2漂白,并对酶处理浆在H2O2漂白前后白度和强度性能进行测定。研究结果表明,利用半纤维素酶PulpzymeHC、纤维素酶Novozym476对马尾松未漂磨石磨木浆(GP)进行预处理,可有效提高漆酶NS51003处理马尾松未漂GP的效率,更加有效的提高纸浆的白度及强度性能,而且适当的预处理可使纸浆具有更好的可漂性,从而使H2O2漂白后的酶处理浆具有更高的白度和更好的强度性能。     

秸秆纤维自生胶合纤维板性能的研究——漆酶、半纤维素酶处理对纤维板性能的影响

研究酶处理工艺对秸秆纤维自生胶合性能的影响和酶处理秸秆纤维的优化条件,为制备无甲醛自生胶粘纤维板提供实验依据。选择漆酶、半纤维素酶为处理剂,以温度、pH值、酶处理时间和酶用量为主要因素进行正交试验。结果表明,漆酶处理最佳条件为:温度45~50℃,反应时间2h,pH值为7,用量45U/g。半纤维素酶处理秸秆纤维的最佳条件:温度50℃,反应时间2~2.5h,pH值为5~6,用量15U/g。该实验为制备力学性能优良的秸秆纤维自生胶合纤维板提供了理论依据。     

废纸脱墨浆预处理及其酶解性能研究

以预处理后的废纸脱墨浆为底物,纤维素酶和纤维二糖酶为水解酶,研究了不同预处理方法（包括Na₂SO₃、H₂O₂、HCl）对酶解得率的影响。结果表明：与原料相比,3种预处理方法都不同程度地提高了纤维素含量,增加底物的比表面积,降低纤维素的结晶度,促进酶水解;其中,H₂O₂预处理后的废纸脱墨浆的酶解得率最高,为91.67%,其次是亚硫酸钠预处理和盐酸预处理,得率分别为87.57%和82.49%。     

纤维素酶木聚糖酶和淀粉酶用于混合办公废纸脱墨的研究

研究了纤维素酶、木聚糖酶及淀粉酶在混合办公废纸脱墨中的协同作用,优化了混合办公废纸酶法脱墨的工艺条件。研究表明,两种单一组分的内切酶Novozym613和Novozym476与木聚糖酶以及α-淀粉酶的协同作用可以明显改善脱墨效果,与化学脱墨浆相比,酶法脱墨浆的尘埃度大大下降,并且两者的物理强度相差不大。     

混合酶用于激光打印废纸脱墨的研究

将生物脱墨技术应用于惠普激光打印废纸脱墨工艺中,在尽量减少碱的用量或完全不用碱的情况下,达到了脱墨的效果和环保的目的。比较了纤维素酶、淀粉酶和脂肪酶以及它们的混合酶对脱墨的影响。分别研究了酶种类和混合酶的配比、温度、pH值对脱墨效果的影响。实验结果表明:纤维素酶和淀粉酶的混合使用有较好的脱墨效果,能使脱墨浆白度达到76.93%(ISO),接近白纸的白度80.48%(ISO)。其最佳工艺条件为:反应温度40℃、pH=9—10、纤维素酶与淀粉酶质量比=1∶1.5。为脱墨工艺的研究提供了理论依据。     

半纤维素酶添加对碱处理甘蔗渣结构及酶解的影响

半纤维素作为木质纤维素的重要组分之一,通过氢键与纤维素的微纤丝结合,严重阻碍了纤维素表面与纤维素酶的接触,降低了酶解的效率。该试验以碱处理甘蔗渣作为底物,通过添加不同量的半纤维素酶去除不同比例的半纤维素。通过成分分析、X射线衍射(XRD)和扫描电镜(SEM)等手段分析添加半纤维素酶前后残渣的结构和酶解特性变化,发现随着半纤维素酶添加量的增大,残渣中木质素所占的比例逐渐增大,结晶指数逐渐增大,电镜表面沟壑逐渐加深,纤维束之间结构变得疏松。以半纤维素酶处理过的甘蔗渣作为底物,按照5FPU/g底物加入纤维素酶水解72h,与不添加半纤维素酶对照组相比,添加1600U/g半纤维素酶处理的试验组木聚糖的转化率提高了74.24%,葡聚糖转化率提高了35.30%。通过半纤维素酶添加可以有效促进纤维素酶解过程的进行,节约反应时间提高酶解转化率。     

马尾松化学热磨机械浆酶法改性研究

利用漆树漆酶/介体体系对马尾松化学热磨机械浆进行生物酶处理及后续H2O2漂白,探索漆酶生物改性最佳工艺条件。结果表明,在漆酶用量为2.0 U/g,2,2’-连氮-二(3-乙基噻唑-6-磺酸)(ABTS)用量0.5%,酶处理温度50℃,酶处理时间60 min时,与对照浆相比,纸浆白度可提高3.0%ISO,抗张指数、撕裂指数分别提高22.5%、7.9%。纤维长度、粗度分析及扫描电镜谱图显示,漆酶处理只发生在纤维表面,有利于表面木素的降解溶出,从而提高了纸浆的白度和可漂性。     

角质酶/表面活性剂体系对混合办公废纸的协同脱墨作用

角质酶能够水解可溶性酯、不溶性甘油三酯和各种聚酯，因此可以水解油墨中的连接料，有代替脂肪酶应用于废纸脱墨领域的潜能。利用角质酶和实验室复配得到的表面活性剂协同应用于混合办公废纸脱墨领域，探讨其脱墨效果和最优工艺，并与常用商业脂肪酶进行脱墨效果比较。结果表明，角质酶在酶用量10 U·g^-1，酶处理时间30 min，酶处理温度50℃，表面活性剂用量0.2%的条件下可以达到最优效果。与脂肪酶/表面活性剂以及单独用表面活性剂脱墨相比，角质酶脱墨后纸页的白度与油墨去除率更高，纸页的机械强度也较好。通过纸页性能的对比和扫描电镜（SEM）观察，角质酶的脱墨效果较脂肪酶更佳，角质酶/表面活性剂体系对混合办公废纸脱墨效果较好。     

Deinked and acetylated fiber of newspapers

Recently, the incorporation of lignocellulosic materials as reinforcing agents or as fillers in polymer composites has received an increased attention. Although natural fibers have a number of advantages over glass fibers, the strong polar character of their surface is a limiting factor, as compatibility with strongly apolar thermoplastic matrices is very low. Such problems of incompatibility may be overcome with fiber pretreatments, which can enhance compatibility, albeit having a negative impact on the economics. In this study, the newspaper is deinked and acetylated. The effect of esterification between the acetyl groups and the hydroxyl groups of the fiber was examined by Fourier transform infrared. X‐ray diffraction and scanning electron microscopy were used to characterize the crystallinity and the surface morphology of the untreated deinked and acetylated fibers (newspaper). The thermal stability of deinked and acetylated fibers was slightly decreased. It was also shown that the deinking increased the crystallinity of newspaper fibers while acetylating decreased this crystallinity. Cellulose acetate is one of the most important cellulose derivatives and its main applications are its use in composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

影响酶法脱墨效果的主要因素

研究了含纤维素酶和半纤维素酶的混合酶液对进口美国废报纸的脱墨效果及影响油墨去除率的主要因素。在所研究的 5个主要因素中 ,废纸碎浆时间、酶处理浆浓的影响最显著。     

废旧新闻纸中性脱墨剂的研究

以国产废旧新闻纸为脱墨对象,用8种表面活性剂在中性条件下对其进行脱墨考察,包括单组分、双组分、三组分、四组分表面活性剂复配体系的脱墨考察。进行了不同质量比表面活性剂的脱墨实验,选择出了合适的中性脱墨剂。结果表明:脱墨剂复配质量比为m(AEO-9)∶m(Tween-60)∶m(AEO-7)∶m(K12)=10∶10∶55∶25时,成纸的白度可提高11.43%ISO,脱墨浆得率89%。     

Spectroscopic Study of Tempo-Oxidized Deinked Pulp

Abstract

Deinked pulps are not currently used in value-added paper manufacturing. To implement their use, both strength and optical properties must be improved. TEMPO oxidation has been shown to improve strength properties of thermomechanical and deinked pulps. However, a significant reduction of the pulp brightness results due to yellowing of mechanical fibers. Spectroscopic techniques were used to investigate the effect of TEMPO oxidation on deinked fiber properties. Fourier transform infra-red (FTIR) spectroscopy and UV/VIS spectrum showed that oxidation conditions are driving important chemical reactions that affect optical properties. Results indicated that ortho-quinone compounds as well as carboxylic groups are generated depending on oxidation conditions resulting in pulp brightness decrease. Spectroscopic studies also revealed that residual ink detachment from fiber surfaces is occurring during oxidation contributing to improve pulp brightness.     

桉木浆纳/微米和脱脂棉纳米纤维素的形貌分析

用环境扫描电子显微镜和透射电子显微镜表征了桉木浆纳/微米和脱脂棉纳米纤维素的形貌。环境扫描电子显微镜观察桉木浆纳/微米和脱脂棉纳米纤维素表面形貌不同,桉木浆纳/微米纤维素主要呈棒状,长度小于20 μm,直径可达0.377 μm;脱脂棉纳米纤维素主要呈球状,长度小于0.5 μm。利用环境扫描电子显微镜,脱脂棉纳米纤维素超声波破碎后直接观察和再经冷冻干燥后观察表面形貌有一定的差异。透射电子显微镜观察桉木浆纳/微米纤维素和脱脂棉纳米纤维素的长度可达到纳米级。     

Durability of thermomechanical pulp fiber-cement composites to wet/dry cycling

Previous research efforts on pulp fiber-cement composites have largely concentrated on kraft pulp fiber composites. In this research program, thermomechanical pulp (TMP) fibers were investigated as an economical alternative to kraft pulp fibers as reinforcement in fiber-cement composites. Prior to wet/dry cycling, TMP composites exhibited increased first crack strength, but lower peak strength and lower post-cracking toughness, as compared to unbleached and bleached kraft pulp composites at equivalent fiber volume fractions. It is believed that this behavior can be attributed to the lower tensile strength and shorter fiber length of TMP fibers as compared to kraft fibers. After 25 wet/dry cycles, TMP composites showed losses in first crack (peak) strength and post-cracking toughness. However, TMP composites exhibited a slower progression of degradation during wet/dry cycling than composites containing bleached or unbleached kraft fibers.     

Synergistic effect of combined fibers for spalling protection of concrete in fire

This study demonstrates the synergistic effect of some particular combination of fibers that can provide significantly better spalling protection of concrete in a fire than single fiber by themselves at the same fiber content level. Various combinations of polypropylene, polyvinyl alcohol, cellulose and nylon fibers were investigated. Fire tests were conducted in accordance with ISO-834. The combination of nylon (9 mm length) and polypropylene (19 mm length) fibers found to provide the most optimum results. By combining these two fibers, the same level of spalling protection was achieved by three times less fiber content than the single type of 0.10% polypropylene fiber commonly prescribed. A “fiber effectiveness parameter” is proposed which is a function of total number of fibers per unit volume and length of fiber. This parameter is useful in providing quantitative explanations of various fiber additions and their spalling results in fire.