Carbohydrate reactions during treatment of kraft pulp and cotton with alkaline peroxide

Abstract The effect of increased fiber charge on refining, cationic starch adsorption, and hornification was examined. Two pulps were investigated: (1) a softwood (SW) kraft pulp (KP) which was bleached elementally chlorine-free (ECF) and served as control; and (2) a control pulp treated with alkaline peroxide, which had a higher fiber charge. It was shown that increased fiber charge can improve the efficiency of the refining treatment, as indicated by differences in tensile index refined from 0 to 1000 revolutions. When the control pulp was refined from 4000 to 8000 revolutions, the tensile index decreased. In contrast, the tensile index of the higher fiber charge pulp (HCP) was higher under the same refining conditions. Upon addition of 2% cationic starch to both pulps, the tensile index of the control pulp increased by 13.7% and that of HCP by 23.7%. Atomic force microscopy did not reveal differences in the surface morphology of the two pulps with and without cationic starch adsorption. Peroxide treatment enhanced the fiber charge of the never-dried pulp. This was beneficial in reducing hornification when pulp was dried at 105°C. However, if the once dried pulp at 105°C was treated with peroxide, this resulted in a drastic decrease in intrinsic viscosity of the pulp and lower tensile and burst indices of the test sheets.

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Recombinant manganese peroxidase (rMnP) from Pichia pastoris. Part 2: Application in TCF and ECF bleaching

Holzforschung ◽

10.1515/hf.2010.018 ◽

2010 ◽

Vol 64 (2) ◽

Cited By ~ 9

Author(s):

Haowen Xu ◽

Gary M. Scott ◽

Fei Jiang ◽

Christine Kelly

Keyword(s):

Pichia Pastoris ◽

Manganese Peroxidase ◽

Kraft Pulp ◽

Energy Savings ◽

Strength Properties ◽

Enzymatic Treatment ◽

Peroxide Bleaching ◽

Alkaline Peroxide ◽

Elemental Chlorine ◽

Ecf Bleaching

AbstractThe recombinant manganese peroxidase (rMnP) produced from the yeastPichia pastorishas been investigated in totally chlorine free (TCF) and elemental chlorine free (ECF) bleaching sequences for improving the bleachability of kraft pulps. In TCF bleaching, oxygen delignified hardwood kraft pulp was treated with rMnP, followed by a sequence combining a chelating and alkaline peroxide bleaching stage. The inclusion of the enzymatic treatment significantly improved the pulp brightness to a level that is difficult to obtain by chemical bleaching alone. Furthermore, the treatment with rMnP resulted in energy savings during pulp refining with PFI mill with a slight improvement in pulp strength properties such as tensile index and burst index. In ECF bleaching, a significant reduction in chlorine dioxide consumption was obtained. A three-stage rMnP treatment combined with alkaline extraction, followed by DED bleaching sequence for hardwood kraft pulp (HWKP) or DEDED bleaching sequence for softwood kraft pulp (SWKP), reduced the total effective chlorine by 41% and 32% for HWKP and SWKP, respectively, compared with the conventional bleaching sequences without enzymatic treatment. The strength properties of the enzyme-treated pulp were also slightly better than that of the control pulp. Further reductions in the consumption of total effective chlorine were obtained when a xylanase pretreatment was incorporated into the bleaching sequence before the repeated rMnP treatment.

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Alkaline peroxide treatment of ECF bleached softwood kraft pulps. Part 1. Characterizing the effect of alkaline peroxide treatment on carboxyl groups of fibers

Holzforschung ◽

10.1515/hf.2007.067 ◽

2007 ◽

Vol 61 (4) ◽

pp. 445-450 ◽

Cited By ~ 6

Author(s):

Zheng Dang ◽

Thomas Elder ◽

Arthur J. Ragauskas

Keyword(s):

Carbonyl Group ◽

Intrinsic Viscosity ◽

Sodium Borohydride ◽

Kraft Pulp ◽

Carboxyl Groups ◽

Kraft Pulps ◽

Peroxide Bleaching ◽

Bleached Kraft Pulp ◽

Alkaline Peroxide ◽

Group Content

Abstract The influence of alkaline peroxide treatment has been characterized on elementally chlorine-free (ECF) bleached softwood (SW) kraft pulp. The results indicate that fiber charge increased with an increase in peroxide charge: a maximum fiber charge increment of 16.6% was obtained with 8.0% more peroxide charge on oven-dried (o.d.) pulp at 60.0°C. Two primary bleaching temperatures of 60.0°C and 90.0°C were investigated during peroxide treatment. Copper number decreased for peroxide charges of 0.5% and 1.0% at 60.0°C and 90.0°C, respectively, then increased with increasing peroxide charge. Both fiber charge and copper number approached constant values when 4.0% or higher peroxide charge was applied. Peroxide treatment on a bleached kraft pulp at 90.0°C resulted in lower fiber charge and lower intrinsic viscosity compared to treatment at 60.0°C. Sodium borohydride (NaBH4) pretreatment was able to protect the fibers from being degraded during peroxide bleaching. Fiber charge and copper number were compared after peroxide treatment of ECF bleached kraft pulp to NaBH4-reduced ECF bleached kraft pulp. The results indicate that the carbonyl group content of fibers is favorable for improving fiber charge after peroxide treatment.

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Prebleaching of eucalypt kraft pulp with OP stages: Effect of an acid pretreatment or chelation step

TAPPI Journal ◽

10.32964/tj11.6.31 ◽

2012 ◽

Vol 11 (6) ◽

pp. 31-38

Author(s):

TATIANA M. PÓVOAS ◽

DINA A.G. ANGÉLICO ◽

ANA P.V. EGAS ◽

PEDRO E.G. LOUREIRO ◽

LICÍNIO M. GANDO-FERREIRA ◽

...

Keyword(s):

Eucalyptus Globulus ◽

Comparative Evaluation ◽

Kraft Pulp ◽

Kraft Pulps ◽

Acid Pretreatment ◽

High Brightness ◽

Pulp Viscosity ◽

Brightness Reversion

We conducted a comparative evaluation of different treatments for the bleaching of eucalypt kraft pulps beginning with OP stages. The treatments tested were (1) an acid chelation stage with DTPA (OQP sequence); (2) a hot acid stage (AOP sequence); and (3) a chelant addition into the alkaline oxygen stage ((OQ)P and A(OQ)P sequences). The latter strategy was also studied for environmental reasons, as it contributes to the closure of the filtrate cycle. The OQP sequence leads to the highest brightness gain and pulp viscosity and the lowest peroxide consumption caused by an efficient metals control. Considering that the low biodegradability of the chelant is a problem, the A(OQ)P sequence is an interesting option because it leads to reduced peroxide consumption (excluding OQP) while still reaching high brightness values and similar brightness reversion to OQP prebleaching, with only a viscosity loss of 160 dm3/kg. Therefore, a hot acid stage could be considered when a separate acid Q stage is absent in a prebleaching sequence of Eucalyptus globulus kraft pulps involving OP stages.

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Application of pure, thermostable, alkali-tolerant xylanase in bleaching of oxygen-delignified pine kraft pulp

TAPPI Journal ◽

10.32964/tj14.11.689 ◽

2015 ◽

Vol 14 (11) ◽

pp. 689-694

Author(s):

QINGZHI MA ◽

QI WANG ◽

CHU WANG ◽

NIANJIE FENG ◽

HUAMIN ZHAI

Keyword(s):

Intrinsic Viscosity ◽

Chlorine Dioxide ◽

High Purity ◽

Kraft Pulp ◽

Alkaline Media ◽

Industrial Scale ◽

Elemental Chlorine ◽

Effect Of Oxygen ◽

Alkaline Tolerant ◽

Ecf Bleaching

The effect of oxygen (O2)-delignified pine kraft pulp pretreatment by high-purity, thermostable, and alkaline-tolerant xylanases on elemental chlorine free (ECF) bleaching of O2-delignification kraft pulp was studied. The study found that xylanase pretreatment preserved the intrinsic viscosity and yield of O2-delignified pulp while causing about 7% of delignification with high delignification selectivity. The xylanases with high purity, higher thermostability (75°C~80°C) in highly alkaline media (pH 8.0~9.5) could be applied on an industrial scale. Pulp pretreatment by the high-purity, thermostable, and alkaline tolerant xylanases could improve pulp brightness or reduce the chlorine dioxide (ClO2) consumption. In a D0ED1D2 bleaching sequence using the same amount of ClO2, the xylanase-pretreated pulp obtained a higher brightness (88.2% vs. 89.7% ISO) at the enzyme dose of 2 U/g pulp; or for the same brightness as control (88.2% ISO), the ClO2 dosage in the D0 stage was reduced by 27%, which represents a 16% savings in total ClO2 used for bleaching.

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Comprehensive evaluation of kraft pulp properties from fast-growing woods

TAPPI Journal ◽

10.32964/tj9.6.34 ◽

2010 ◽

Vol 9 (6) ◽

pp. 34-39

Author(s):

AIYU QU ◽

YANHUI AO ◽

JUN YAN ◽

GUIGAN FANG

Keyword(s):

Kraft Pulp ◽

Comprehensive Evaluation ◽

Evaluation Model ◽

Evaluation Index System ◽

Evaluation Index ◽

Wood Cellulose ◽

Fuzzy Matrix ◽

Fast Growing ◽

Pulp Properties ◽

Evaluation Index Systems

To develop new wood cellulose resources and fast-growing pulpwood plantation fiber sources, it is very important to evaluate their pulping properties. A comprehensive multi-index pulping-suitability evaluation model is investigated in this paper by considering four fast-growing wood species. First, a new evaluation-index system for kraft pulp was developed based on traditional evaluation-index systems. Then, the membership degree of every index was analyzed to obtain a fuzzy matrix. The proportional contribution of each parameter to the main pulping properties could then be determined. Finally, a comprehensive evaluation model of kraft pulp properties was developed. The model is reliable compared with traditional assessment methods. The results confirmed the feasibility and rationality of developing new wood cellulose resources and fast-growing pulpwood plantations using fuzzy comprehensive evaluations.

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Optimization of elemental chlorine-free bleaching for a softwood kraft pulp • part 2: economic analysis of chemical and steam consumption

TAPPI Journal ◽

10.32964/tj9.9.47 ◽

2010 ◽

Vol 9 (9) ◽

pp. 47-53 ◽

Cited By ~ 2

Author(s):

BRIAN N. BROGDON

Keyword(s):

Chlorine Dioxide ◽

Previous Investigation ◽

Kraft Pulp ◽

Energy Costs ◽

Alkaline Extraction ◽

Stage Versus ◽

Kraft Pulps ◽

Steam Consumption ◽

Elemental Chlorine ◽

Softwood Kraft Pulp

Our previous investigation [1] re-analyzed the data from Basta and co-workers (1992 TAPPI Pulping Conference) to demonstrate how oxidative alkaline extraction can be augmented and how these changes affect chlorine dioxide consumption with elemental chlorine-free (ECF) sequences. The current study manipulates extraction delignification variables to curtail bleaching costs with a conventional U.S. Southern softwood kraft pulp. The economic advantages of ~0.35% to 0.65% H2O2 peroxide reinforcement in a 70°C (EOP)-stage versus 90°C (EO)-stage are predisposed to the brightness targets, to short or long bleach sequences, and to mill energy costs. Minimized bleaching costs are generally realized when a 90°C (EO) is employed in D0(EO)D1 bleaching, whereas a 70°C (EOP) is economically advantageous for D0(EOP)D1E2D2 bleaching. The findings we disclose here help to clarify previous ECF optimization studies of conventional softwood kraft pulps.

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Refining Energy Reduction and Pulp Characteristic Modification of Alkaline Peroxide Mechanical Pulp (APMP) Through Enzyme Application

TAPPI Journal ◽

10.32964/tj8.5.19 ◽

2009 ◽

Vol 8 (5) ◽

pp. 19-25 ◽

Cited By ~ 2

Author(s):

PETER W. HART ◽

DARRELL M. WAITE ◽

LUC THIBAULT, ◽

JOHN TOMASHEK ◽

MARIE-EVE ROUSSEAU ◽

...

Keyword(s):

Wood Chip ◽

The United States ◽

Enzyme Treatment ◽

Chemical Application ◽

Alkaline Peroxide ◽

Eucalyptus Wood ◽

Pulp Properties ◽

Pulp Processing ◽

Two Stages ◽

Enzyme Application

Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.

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An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽

10.32964/tj17.03.157 ◽

2018 ◽

Vol 17 (03) ◽

pp. 157-164 ◽

Cited By ~ 3

Author(s):

Shengdan Wang ◽

Wenhua Gao ◽

Kefu Chen ◽

Jinsong Zeng ◽

Jun Xu ◽

...

Keyword(s):

Correlation Coefficient ◽

Congo Red ◽

Kraft Pulp ◽

Cellulose Nanofibrils ◽

Standard Curve ◽

Congo Red Dye ◽

Mechanical Disintegration ◽

Softwood Kraft Pulp ◽

White Water ◽

Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

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