低温氧碱麦草浆的全无氯漂白

单段麦草氧碱浆压力H2O2(Ppt)漂白,在用碱量4%(NaOH计),Na2SiO3用量3%时的脱木素及漂白效果较好,与原浆相比,卡伯值从17.9下降至6.7,下降了62.6%,白度从36.2%ISO上升至73.6%ISO,增加了50.8%,表明Ppt漂白效果明显。压力H2O2漂白后浆料不经螯合直接进行H2O2补漂,与螯合处理后漂白对比,发现两者均可将麦草氧碱纸浆漂至白度80%ISO左右,而采用Ppt-Q-P漂白比Ppt-P漂白的纸浆白度高4.0%ISO左右,浆料黏度在929.6～1 025.0 mL/g之间。     

漆酶和木聚糖酶预处理对麦草浆漂白性能的影响

生物漂白主要目的在于通过对纸浆预处理,减少后续漂白时漂剂用量,降低漂白废水对环境污染,同时改善纸浆性能。通过漆酶/木聚糖酶体系(LXS)和重组木聚糖酶(X)对麦草浆预处理,比较它们对浆料脱木素能力和漂白性能的影响。结果表明:麦草浆经过两种酶预处理后,都能降低浆料卡伯值,而漆酶处理后降低的幅度更大,与原浆和木聚糖酶处理浆相比分别降低32.64%和6.47%,但是在木聚糖酶处理液中能检测到更多的还原糖;两种酶处理浆在后续漂白中漂白至与对照浆相近白度时均能节省50%漂剂用量,且能改善浆料物理强度;比较两种酶对浆料漂白性能的影响,则是在相同漂剂用量时木聚糖酶漂白浆的白度稍高,而浆料得率和强度稍低;两种酶处理浆料的纤维素结晶度测定表明酶处理前后浆料的纤维素的结晶结构没有明显的变化,而且纤维素的结晶度都有不同程度的提高。通过扫描电镜观察以及X射线光电子能谱(XPS)分析,从理论上说明两者脱木素的差异。     

机械力化学效应对麦草浆重组木聚糖酶生物漂白的影响

利用机械力化学作用,以提高木聚糖酶预处理效果。论文研究了磨浆对重组木聚糖酶预处理效果的影响;磨浆前后重组木聚糖酶预处理对浆料漂白性能的影响。研究结果表明:采用机械力化学作用酶处理时比较适合的磨浆时间为5 min,打浆度在30 oSR左右,在酶用量为5 IU/g时,脱木素率达到29.7%,与磨浆前酶处理相比,脱木素率提高了34.4%;磨浆前后的浆料经过重组木聚糖酶预处理,在后续漂白时漂至与对照浆相近白度时(72.6%ISO),分别节省了50%和57.1%用氯量,大大减轻了漂白废水对环境的污染;通过磨浆前后酶处理液高效液相色谱分析、浆料结晶度测定以及扫描电镜的观察,从理论上证实了重组木聚糖酶在助漂时的机械力化学效应,并为它的广泛应用提供了理论依据。     

麦草浆二氧化氯与氧气脱木素效率及相应漂白流程的对比

对麦草浆二氧化氯与氧气脱木素效率及相应的漂白流程进行了对比研究。结果表明,ClO2脱木素(D0)对木素的修饰和改性效果好于氧脱木素(O),在脱木素率低于及接近氧脱木素率的条件下,D0浆的可漂性均大于O浆。在D0段和O段脱木素率相同的条件下,采用D0A/QP、D0EP漂白流程漂后纸浆白度分别比OA/QP漂白流程高11.2和10.3个百分点。D0段废液和相应D0A/QP漂白流程三段混合废水的CODCr负荷均比O段和OA/QP漂白流程混合废水的CODCr负荷轻。D0段和O段废液的紫外光谱都呈现出木素苯环的特征吸收。纸浆的FT-IR谱图分析表明,D0浆和O浆中的羟基和羰基数量增多,随着漂白的进行,羰基等主要发色基团逐渐消除,纸浆白度得到提高。纸浆纤维形态的SEM分析显示,D0段和相应的D0A/QP漂白流程对纤维表面的破坏和损伤较O段和相应的OA/QP漂白流程轻。     

表面活性剂Tween 80对麦草浆次氯酸盐漂白的影响

研究了聚氧乙烯山梨醇酐单油酸酯(Tween80)对麦草烧碱浆次氯酸盐漂白的助漂作用。对次氯酸盐与Tween80同时漂白、次氯酸盐漂白后再用Tween80后处理以及Tween80预处理加次氯酸盐漂白(分别以H/T、HT和TH表示)三种不同组合的漂白方式对纸浆白度、粘度及主要强度指标的影响进行了综合比较,结果发现Tween80在HT漂序中的助漂效果较好。在HT漂白中,当Tween80的用量为0.8%时,漂白浆的白度增加最多,粘度虽然有所下降,但仍大于对照次氯酸盐漂白浆,其抗张强度也较好,撕裂强度基本不变,但耐破和耐折强度有不同程度的下降。     

麦草亚铵法氧脱木素浆蒽醌强化次氯酸盐漂白

对麦草亚铵法氧脱木素浆进行蒽醌强化的次氯酸盐漂白工艺的研究,结果表明:在所选四因素三水平漂白工艺中,影响纸浆白度和卡伯值的主要因素是用氯量,当用氯量为7%时,纸浆白度为71.1%ISO;另外,在50℃和80℃的条件下,对麦草亚铵法氧脱木素浆分别进行添加氨基磺酸和蒽醌的漂白研究,发现次氯酸盐漂白时添加蒽醌比添加氨基磺酸的漂白效果好,不仅漂白浆的白度和黏度均得到提高,而且脱木素能力也显示加强。     

E—An—76对桦木硫酸盐浆无氯漂白流程的影响

本文研究了半纤维素酶E—An—76对桦木硫酸盐浆无氯漂白流程的影响．研究结果表明：在桦木硫酸盐浆OEDP漂白过程中插入E－An－76组成的OXEDP流程与原漂程比较，可节省大量化学漂剂的用量而保持白度和得率。     

四乙酰乙二胺在纸浆漂助漂白中作用的研究

本文主要论述了四乙酰乙二胺对纸浆的无氯漂白和在有氯漂白过程中的助漂作用,实现常温下过硼酸钠的无氯漂白,以及有氯漂白的减氯和提高白度。     

磺酸基氯(溴)铝酞菁漂白杀菌性能的研究

研究了磺酸基氯(溴)铝酞菁的漂白杀菌性能。当浓度为0.750ppm～0.755ppm时,被漂白基质的白度值为61.73%-66.41%,提高15%;对棕色染料污布当光漂剂为0.3750ppm-0.3775ppm时,白度值为41.21%～46.04%(洗涤光照同时)和40.37%～54.41%(洗涤光照分别进行),白度值增加15%。在标题化合物浓度为0.1ppm时,经1小时可将浓度为3.82×105cfu/ml的活菌全部杀灭;当浓度为1ppm时,经20分钟可将浓度为8.25×104cfu/ml细菌全部杀灭,杀菌对数值大于4.9。     

芦苇烧碱-蒽醌浆生物漂白的研究

对芦苇烧碱-蒽醌浆进行漆酶/介体体系脱木素处理结合过氧化氢漂序进行漂白。结果表明,分别利用三种介体HBT、VIO和NHA辅助漆酶脱木素,导致浆的白度均有不同程度的降低,降低的幅度与介体种类和用量有关。在相同浓度时,浆白度的降低幅度随介体的氧化还原电势的增大而增大。根据过氧化氢漂白的结果,可以认为LMS-QP最佳处理条件为使用介体NHA,用量为0.5%,漂白时间为2 h。对用2%VIO为介体脱木素后的浆残余木素分析表明,经过漆酶/介体体系处理浆料,浆残余木素中的羰基含量相对提高。     

Effect of Totally Chlorine Free and Elemental Chlorine Free Sequences on Whole Stem Kenaf (Hibiscus cannabinus) Pulp Characteristics

Totally chlorine free (TCF) and elemental chlorine free (ECF) single and multistage sequences were used to bleach whole stem kenaf pulp. The results indicated that in contrast to unbleached kraft wood pulps, kraft kenaf pulps can be easily bleached to a brightness of 91.4% using a four-stage TCF [Q₁(PO)Q₂P] bleaching sequence. The ECF bleaching pulps had slightly higher selectivity and yield than those of the TCF bleached pulps. The strength properties of the TCF [Q₁(PO)Q₂P] and ECF (D₁ED₂EP) bleached pulps were comparable, with the exception of tear index and tensile index, which were slightly higher and lower for TCF pulps, respectively.     

Polyoxometalate catalyzed ozonation of chemical pulps in organic solvent media

Polyoxometalate (POM) catalyzed ozonation of chemical pulps in organic solvent media was found to be particularly effective and selective environmentally benign bleaching approach providing a way for substantial increase in pulp brightness, viscosity and degree of delignification in comparison with other ozone-based bleaching techniques. A series of tested low-boiling polar aprotic and protic organic solvents showed a well-defined capacity for ozonation improvement in the presence of Keggin-type heteropolyanion [PMo₇V₅O₄₀]⁸⁻ (HPA-5). Even moderate solvent proportion of 6% (w/w) in the reaction solution caused additional gain in brightness up to 3.4% ISO with simultaneous increase in pulp viscosity up to 8.8% and lignin removal up to 18.9% after HPA-5 catalyzed ozonation (0.8% O₃; 0.5 mM HPA), as compared with the control solvent-free process. An aqueous acetone solution was found to be the preferred reaction medium in terms of pulp brightening and delignification. Under optimized conditions, the POM-catalyzed ozonation of eucalypt kraft pulp in acetone/water solution showed remarkable brightness improvement by 15.1% ISO with additional lignin removal by 39.4% and increase in intrinsic viscosity by 3% in comparison with pulp bleached in water media.     

Integrating laccase–mediator treatment into an industrial‐type sequence for totally chlorine‐free bleaching of eucalypt kraft pulp

Enzymatic delignification using the high‐redox potential thermostable laccase from the fungus Pycnoporus cinnabarinus and a chemical mediator (1‐hydroxybenzotriazole) was investigated to improve totally chlorine‐free (TCF) bleaching of Eucalyptus globulus kraft pulps. Different points of incorporation of the enzyme treatment into an industrial‐type bleaching sequence (consisting of double oxygen, chelation and peroxide stages) were investigated in pressurized laboratory reactors. The best final pulp properties were obtained using an O? O? L? Q? PoP sequence, where a laccase–mediator stage (L) was incorporated between double oxygen and chelation. The worse results, when the enzymatic and chelation treatments were combined in a unique stage, seemed related to partial inhibition of laccase‐mediator activity by the chelator. The new TCF sequence including the laccase stage permitted to improve eucalypt pulp delignification to values around kappa 5 (hexenuronic acid contribution over 50%) compared to kappa 7 using only TCF chemical reagents. In a similar way, the final brightness obtained, over 91% ISO, was 3–4 points higher than that obtained in the chemical sequences. Although technical and economic issues are to be solved, the results obtained show the feasibility of integrating a laccase–mediator treatment into a TCF sequence for bleaching eucalypt kraft pulp. Copyright © 2006 Society of Chemical Industry     

麦草亚铵法氧脱木素浆的短流程漂白

对麦草亚铵法氧脱木素浆进行了P、HP和HQP漂白对比研究,结果表明:在过氧化氢单段漂白时,Na2SiO3的适宜用量为0.4%,在所选过氧化氢用量、NaOH用量、温度和时间的四因素三水平方差分析漂白工艺中,影响纸浆白度的主要因素为NaOH用量;而采用HP和HQP漂白时,漂白浆的白度分别达到78.1%(ISO)和81.9%(ISO),可见采用螯合处理的效果明显。     

杨木硫酸盐浆在生物酶处理过程中纤维表面积的变化

漆酶 /助剂对杨木硫酸盐浆进行生物漂白 ,用染色法对漂白过程的纸浆纤维的比表面积进行测定。研究结果表明 ,漆酶 /助剂可有效地提高纤维的表面积、白度 ,降低卡伯值 ,而对纸浆的粘度影响不大。     

枫香树材清洁制浆技术

对速生阔叶木枫香树材的纤维形态、主要化学组成、清洁制浆及绿色漂白工艺进行了一系列探讨。结果显示,枫香木纤维平均长度较长,长宽比均比杨木大,且其综纤维素和戊聚糖含量高而Klason木素含量低,是一种很有发展潜力的制浆造纸原料。采用硫酸盐法制浆,蒸煮后所得细浆得率为49.9%,卡伯值为23.0,白度为23.8%ISO,黏度为734.7 mL/g。利用环境友好型漂白法——氧脱木素技术处理该枫香树材硫酸盐浆,并在此过程中创造性地使用助剂蒽醌。四因素三水平正交试验结果表明:用碱量、氧压、温度和时间对枫香树材硫酸盐浆添加蒽醌氧脱木素后浆料的性能均有很大的影响。其中,温度对得率、卡伯值、白度和黏度等的影响最大,时间对卡伯值、白度和黏度的影响最小。枫香树材硫酸盐浆添加蒽醌氧脱木素的较为适宜的工艺为:用碱量3%,氧压0.7 MPa,温度105℃,保温时间90 min,浆浓20%,MgSO4用量0.5%,蒽醌用量0.1%。在该条件下所得浆料得率90.7%,卡伯值7.0,黏度545.1 mL/g,白度51.0%ISO,脱木素选择性8.42×10-2。与相同条件下常规氧脱相比,卡伯值和白度相近,但得率、黏度和脱木素选择性都有所提高。蒽醌在枫香树材硫酸盐浆氧脱木素过程中可保护碳水化合物,提高脱木素选择性,是一种良好的氧脱木素助剂。     

高纯耐热耐碱木聚糖酶预处理对杨木KP浆漂白特性的影响

研究了耐热耐碱木聚糖酶X对杨木硫酸盐浆预处理的选择性及其对无元素氯(ECF)漂白特性的影响。结果表明:该木聚糖酶预处理具有高的助漂选择性,预处理对纸浆的得率及黏度影响不大;该木聚糖酶对温度及pH的适应范围较广,在温度为75～80℃、pH 8.0～9.5范围内都可以发挥有效的助漂作用,尤其在温度80℃、pH 8.0、酶用量2 IU/g的条件下更能发挥酶效;耐热耐碱木聚糖酶X预处理可减少漂白ClO2用量,当达到对照浆相同白度(90%ISO)时可减少D0段26%～27%的ClO2用量(相当于总用氯量的16%)。     

木聚糖酶预处理对NaOH-AQ法麦草浆H_2O_2漂白效果的影响

探讨了木聚糖酶预处理对麦草化学浆 H2 O2 漂白可漂性等的影响。结果表明 :与对照浆漂至相近白度 ,木聚糖酶预处理后可节省 H2 O2 用量 4 0 %以上 ,且浆的强度变化不大 ;酶预处理还可以改善 H2 O2 漂后浆的滤水性能 ,提高漂白浆的白度稳定性。