ENZYMATIC BLEACHING OF WHEAT STRAW SODA-AQ PULP BY LMS TREATMENT

Laccase has been proven that it has a good selectivity and efficiency in pulp bleaching. In this paper, the effects of LMS (Laccase Mediator System) treatment on delignification and bleaching of wheat straw pulp at various conditions, such as laccase dosage,temperature, oxygen pressure and pH, were investigated. The TCF sequence including LMS can bleach the wheat straw pulp to 81% ISO brightness with good strength. The synergetic biobleaching of LMS and xylanase of wheat straw pulp was also investigated. It was found that the final brightness and strength of synergetic biobleaching pulps increased to a certain extent and the bleaching selectivity was improved. The combination of the enzymes is feasible for the delignification and bleaching.     

BLEACHING OF SULFONATED CMP FROM BIO-TREATED WHEAT STRAW

INTRODUCTIONThe increasing consumption of paper and paper board all over the world and the more and more serious legislative constraints on forest resources intensify the shortage of pulping materials. Agricultural residues such as wheat straw are of increasing interests in countries and areas which have abundant plantation of agricultures and are lack of wood supply. One of the problems associated with the wheat straw pulp was the low pulp yield and low bleachability relative to wood pulp…     

木聚糖酶漂白机理的形态研究

用扫描电镜观察经木聚糖酶处理过的纸浆纤维样品,发现木聚糖酶可使纤维的表面和内部超微结构发生变化。结果表明,产自于黑曲霉的１＃木聚糖酶和产自于里氏木霉的２＃木聚糖酶由于含纤维素酶活较高,故经处理后的纤维结构遭受严重损伤,因此也降低了纤维强度;而产自于荧光假单孢菌的３＃木聚糖酶由于含纤维素酶活较低,故经预处理后可使纤维表面和横断面上产生比较均匀的孔洞和裂隙,既可增加后续漂剂的渗透性,又不影响纤维的强度,是马尾松ＫＰ浆进行生物预处理的较为理想的木聚糖酶。     

硫酸盐木浆漂白前木聚糖酶预处理的研究

研究了木聚糖酶用于硫酸盐木浆 H2 O2 漂白前预处理的工艺条件 ,结果表明 ,预处理最佳工艺条件为 :酶用量为每克浆 2 0 IU ,时间 3h,浆浓为 6 %。在相同的 H2 O2 漂白条件下 ,经酶处理后的浆料白度可提高 2 %～ 3% SBD。     

改良木聚糖酶辅助漂白芦苇浆的工艺研究

采用分子改良后的木聚糖酶对芦苇浆进行生物预处理,考察了改良木聚糖酶辅助漂白的效果。结果表明,酶预处理可以降低CEH三段漂白中氯化C段的氯气用量60%。改良木聚糖酶预处理辅助漂白芦苇纸浆最佳条件为:pH为7.0,温度60℃,浆浓(质量分数)5%,酶用量12μmol/(min.g),预处理时间60 min。在此条件下C段氯用量降至对照的40%时,酶处理漂后样品白度可达到84.0%(ISO),高出对照样的白度3.7%(ISO)。改良木聚糖酶预处理还能够改善纸浆漂后样的物理性能。     

低纤维素酶活木聚糖酶对麦草浆的辅助漂白作用

利用低纤维素酶活木聚糖酶对麦草浆进行预处理,研究木聚糖酶在氯、碱、次氯酸盐(CEH)三段漂白中对氯气用量的减少以及对漂白过程中纸浆木质纤维组分变化的影响。结果表明:经过木聚糖酶预处理,在保证纸浆漂后白度的同时,氯气用量可以减少50%;木聚糖酶预处理对纸浆中的木素有脱除作用,且能促进木素在碱抽提过程中的溶出,但木聚糖酶对戊聚糖和纤维素也有不同程度的降解作用;酶处理浆漂后的木素和半纤维素的含量略低于未经处理的对照浆,纤维素含量则略高于对照浆。     

XYLANASE PREBLEACHING ON NaOH-AQ WHEAT STRAW PULP

INTRODUCTIONChina is a kingdom of straw pulps and wheat strawhas a dominant proportion in non-wood fiberresource. Wheat straw is inexhaustible annual plant.When it is used to make pulp and paper, there is noproblem of affecting afforestation and energyconsumption. In order to make full use of existedresource and make products of good quality witheffluent of low pollution loading, the study of wheatstraw pulp has realistic meaning. On the other hand,application of biotechnology has penetra…     

KRAFT WOOD PULP TCF AND ECF BLEACHING WITH ENZYME PRETREATMENT *

针叶木硫酸盐浆用木聚糖酶Ｉｒｇａｚｙｍｅ４０＿Ｘ４进行预处理,然后进行各种无元素氯（ＥＣＦ）和全无氯（ＴＣＦ）漂白．实验结果表明,酶预处理能提高后续漂白效果,提高白度,降低卡伯值,并改善纸浆的粘度,在不用元素氯的情况下,能将纸浆漂白到８８％ＩＳＯ以上的白度     

漆酶/木聚糖酶体系去除废新闻纸脱墨浆中胶黏物的研究

废纸浆因含有大量的细小组分和阴离子杂质,极大地影响了纸机网部的滤水性能和成纸质量。笔者应用漆酶处理废新闻纸脱墨浆,研究其去除胶黏物的效果。结果表明：漆酶/木聚糖酶体系（LXS）处理废纸脱墨浆,能有效去除浆料中胶黏物,尤其是漆酶/木聚糖酶体系处理后碱抽提（LXS+E）去除效果更佳。在酶用量为15 μmol/(min·g)时,LXS和LXS+E处理后与原浆相比,浆中胶黏物分别降低了51.91 %和68.43 %,减轻了后续工序除胶黏物的负荷,改善了浆料滤水性。当漆酶用量为15 μmol/(min·g)时,LXS和LXS+E处理浆与原浆相比,打浆度分别降低了15.22 %和28.26 %。此外通过这两种方法处理还能提高浆料的强度,而浆料得率却稍有下降。     

耐热木聚糖酶助漂针叶木硫酸盐浆的研究

探讨了嗜热真菌耐热木聚糖酶助漂针叶木硫酸盐浆的应用前景.着重研究了应用耐热木聚糖酶进行生物助漂的酶用量、酶处理的pH值以及漂白用氯量等影响因素.结果表明,在不影响纸浆的各项性能的情况下,经酶处理的纸浆白度相比对照增加1.06%~5.11%ISO.同时,酶处理纸浆漂白时可减少漂白用氯量.另外,在偏碱性条件下进行酶处理对纸浆漂白效果的影响较为显著.纸浆纤维的扫描电镜结果显示,酶未对纤维造成损伤,而是改善了纸浆纤维的可漂性.该耐热木聚糖酶非常适宜应用于酶助漂.     

THE STUDY ON TCF BLEACHING OF NS REED PULP

In this paper, we have researched TCF bleaching on reed pulp including oxygen delignification, oxygen delignification with H2O2 intensification and H2O2 bleaching. The results show that Op-P bleaching process on NS reed pulp is suitable and the brightness of bleached pulp is up to 82% ISO.     

桉木硫酸盐浆LMS生物漂白的研究

进行了桉木硫酸盐将漆酶一介体系统（LMS）生物漂白的研究,漆酶由白腐菌Panus conchatus固体发酵并分纯化而制得;一种新的介体－－N－羟基乙酰苯胺（NHA）自行合成,采用L／MQP漂白流程,仅用2％（质量分数）的H2O2就将桉木常规硫酸盐浆（EMCC－O）可达到87．6％ISO的白度,生物漂白的CK浆和EMCC－O浆的粘度都很高,说明漆酶／NHA生物漂白的脱木素选择性很好。     

MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.     

STUDY ON THE ELEMENTAL CHLORINE FREE BLEACHING OF BAMBOO KRAFT PULP

1INTRODUCTIONChina is a country using the most variety of non-wood fiber raw material and is the largest country producing non-wood fiber pulp and paper in the world[1]. Bamboo is one kind of the main non-wood species for papermaking in China. Although the structure of raw materials for papermaking has being adjusted through increasing the proportion of wood pulp and by effectively utilizing waste paper source, non-wood species will still remain an important fiber resource[1,2].At present…     

CHLORINE DIOXIDE BLEACHING OF NaOH-AQ WHEAT STRAW PULP

The influences of chlorine dioxide bleaching of NaOH-AQ wheat straw pulp were studied in this paper. The results showed that the optimal conditions were as follows: chlorine dioxide dosage 1.0%,initial pH 4.0, pulp consistency 8% and 70℃ for 150 minutes. Furthermore, some ways of rebuild the conventional CEH bleaching sequence were put forward, such as CED, DED, DCED, and we draw a conclusion that CED, DCED has higher bleaching efficiency than the CEH bleaching process.     

ENZYMATIC DEINKING OF OLD NEWSPRINT WITH CELLULASES AND XYLANASE

The enzymatic deinking and fiber modification of old newsprint (ONP) with several cellulases and xylanase were investigated and the suitable enzyme candidates were selected for ONP deinking in this paper. The results demonstrated that the cellulases and hemicellulases could significantly improve the deinking efficiency and fiber modification.Moreover, the synergistic effects of Novozym342 and xylanase (HC) can further enhance the deinking performance, reduce the dirt count and improve the brightness of resulting pulp. Additionally, compared to deinked pulps, obtained from conventional chemical materials, enzymatically deinked pulps had better bleachability, and the brightness of the bleached pulp reached 59.1% ISO, 9% ISO higher than the unbleached pulp.     

活化剂在麦草硫酸盐浆中无氯和少氯漂白中的应用

在麦草ＫＰ浆的无氯和少氯漂白程序中使用活化剂,可促进脱木素作用并提高浆的白度。在氧脱木素前用ＮＯ２,硫酸和过氧酸进行预处理比较,以ＮＯ２效果最佳。ＮＯ２用量２％,处理后浆的卡伯值比未处理降低了６％,白度提高４％,粘度只下降１．６％。在Ｄ／ＣＥＤＤ漂白程序中,漂前用对有效氯用量８％的Ｓ１２预处理,白度提高２．３％ＩＳＤ,粘度基本无变化;活化剂ＴＡ用于ＮＯＰ三段漂的Ｐ段,用量４％（对浆）,可提高白度４．３％ＩＳＯ,粘度也有明显提高。本试验采用ＧＯＰＡＰＴＡ无氯漂白程序,可使麦草ｋｐ浆漂后白度达８０％ＩＳＯ,但粘度下降较大     

INFLUENCES OF BLAECHING ADDITIVES ON REED PULP FAST BLEACHING

SUMMARYWith the development of paper machine and the enlarger of cooking capability, higher requirement of bleaching system in paper mill is brought forward. At present, many straw-pulp mills completed single-stage hypochlorite bleaching through horizontal bleaching machine, which had the disadvantages of large area and low product ability. So there always was no enough space for paper mills to increase the product ability. Bleaching process became the key handicap to increase the product a…     

THE TCF BLEACHING OF NS-AQ ASPEN HIGH YIELD CHEMICAL PULP

INTRODUCTIONNowadays, under the pressure of energy crisis, Methods押The pulp was put in the high-density polyethylene plastic bag in the of thermostatic water bath where the pulp was treated with chelated environment pollution and market competition, the pulp industry has being developed in the direction of "Three Highness" and " Three Lowness". "Three Highness" means high yield, high strength and high brightness; on the other hand, " Three Lowness" means low energy consumption, low wa…     

HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.