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

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 445-450 ◽  
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.

Location and fate of carboxyl groups in aspen alkaline peroxide-impregnated chemithermomechanical pulp fibres during alkaline peroxide bleaching

2012 ◽  
Vol 47 (3) ◽  
pp. 557-569
Author(s):  
Yingjuan Fu ◽  
Menghua Qin ◽  
Yanzhu Guo ◽  
Qinghua Xu ◽  
Zongquan Li ◽  
...  
Keyword(s):  
Carboxyl Groups ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Pulp Fibres

Multivariate Analysis of Hemicelluloses in Bleached Kraft Pulp Using Infrared Spectroscopy

2016 ◽  
Vol 70 (12) ◽  
pp. 1981-1993 ◽  
Author(s):  
Zhiwen Chen ◽  
Thomas Q. Hu ◽  
Ho Fan Jang ◽  
Edward Grant
Keyword(s):  
Multivariate Analysis ◽  
Infrared Spectroscopy ◽  
Sample Preparation ◽  
Kraft Pulp ◽  
Control Variable ◽  
Discrete Wavelet ◽  
Kraft Pulps ◽  
Bleached Kraft Pulp ◽  
Ft Ir ◽  
Mean Square Errors

The hemicellulose composition of a pulp significantly affects its chemical and physical properties and thus represents an important process control variable. However, complicated steps of sample preparation make standard methods for the carbohydrate analysis of pulp samples, such as high performance liquid chromatography (HPLC), expensive and time-consuming. In contrast, pulp analysis by attenuated total internal reflection Fourier transform infrared spectroscopy (ATR FT-IR) requires little sample preparation. Here we show that ATR FT-IR with discrete wavelet transform (DWT) and standard normal variate (SNV) spectral preprocessing offers a convenient means for the qualitative and quantitative analysis of hemicelluloses in bleached kraft pulp and alkaline treated kraft pulp. The pulp samples investigated include bleached softwood kraft pulps, bleached hardwood kraft pulps, and their mixtures, as obtained from Canadian industry mills or blended in a lab, and bleached kraft pulp samples treated with 0–6% NaOH solutions. In the principal component analysis (PCA) of these spectra, we find the potential both to differentiate all pulps on the basis of hemicellulose compositions and to distinguish bleached hardwood pulps by species. Partial least squares (PLS) multivariate analysis gives a 0.442 wt% root mean square errors of prediction (RMSEP) for the prediction of xylan content and 0.233 wt% RMSEP for the prediction of mannan content. These data all support the idea that ATR FT-IR has a great potential to rapidly and accurately predict the content of xylan and mannan for bleached kraft pulps (softwood, hardwood, and their mixtures) in industry. However, the prediction of xylan and mannan concentrations presented a difficulty for pulp samples with modified cellulose crystalline structure.

scholarly journals Bleached kraft pulp production from Pinus tecunumanii (Eguiluz e Perry)

2005 ◽  
Vol 29 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Leonel F. Torres ◽  
Roberto Melo ◽  
Jorge Luiz Colodette
Keyword(s):  
Kraft Pulp ◽  
Strength Properties ◽  
Kappa Number ◽  
Raw Material ◽  
Kraft Pulps ◽  
Optimum Conditions ◽  
Oxygen Delignification ◽  
Bleached Kraft Pulp ◽  
Pinus Tecunumanii ◽  
Pulp Production

The use of 12-year-old Pinus tecunumanii (Eguiluz e Perry) grown in Colombia was evaluated for bleached kraft pulp production. Kraft pulps of kappa number 30 ± 1 were produced, and oxygen delignified and bleached to 90% ISO with ECF processes. The bleached pulps produced under optimum conditions were evaluated with regard to their strength properties. Pinus tecunumanii wood required low effective alkali charge to reach the desired kappa number and the unbleached pulp showed high oxygen delignification efficiency and bleachability when a OD(EO)DED sequence was used. The bleached pulps presented good physical-mechanical properties, which are comparable to those obtained with more traditional pines such as Pinus taeda and Pinus radiata. The results demonstrate that this tropical pine species is a suitable raw material for bleached kraft pulp production

Reductive degradation of residual chromophores in kraft pulp with sodium dithionite

TAPPI Journal ◽  
2012 ◽  
Vol 11 (3) ◽  
pp. 59-67 ◽  
Author(s):  
HÉLIO J. M. CARREIRA ◽  
PEDRO E. G. LOUREIRO ◽  
M. GRAÇA V.S. CARVALHO ◽  
DMITRY V. EVTUGUIN
Keyword(s):  
Kraft Pulp ◽  
Unknown Origin ◽  
Sodium Dithionite ◽  
Carboxyl Groups ◽  
Kraft Pulps ◽  
Model Compounds ◽  
Muconic Acid ◽  
Reduction Stage ◽  
Reductive Degradation ◽  
Vis Spectroscopy

The focus of this study is the chemistry of reductive bleaching of kraft pulps with sodium dithionite. A set of model compounds mimicking quinone structures, residual lignin structures with conjugated carbonyl/carboxyl groups and muconic acid, among others, was reduced with sodium dithionite and monitored by ultraviolet-visible (UV-vis) spectroscopy. Depending on the chromophore models, either reductive or sulfonation reactions are thought to be responsible for the degradation. No reductive degradation of hexeneuronic acid (HexA) residues was detected, but unsaturated structures of unknown origin were eliminated from the xylan. Additionally, the potential of the reductive stage with either sodium dithionite or sodium borohydride was tested using an industrial pine kraft pulp bleached by OOZEDD sequence. This pulp, with a 88.8% ISO brightness ceiling, exhibited a brightness increase to 90 ± 0.5% in the final reduction stage.

Alkaline peroxide treatment of ECF bleached softwood kraft pulps: Part 2. Effect of increased fiber charge on refining, wet-end application, and hornification

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Zheng Dang ◽  
Thomas Elder ◽  
Jeffery S. Hsieh ◽  
Arthur J. Ragauskas
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Morphology ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Cationic Starch ◽  
Force Microscopy ◽  
Tensile Index ◽  
Alkaline Peroxide ◽  
Atomic Force ◽  
Starch Adsorption

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.

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

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
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.

scholarly journals EFFECT OF ADDITION OF DEINKED PULP TO BLEACHED KRAFT PULP ON TISSUE PAPER PROPERTIES

Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 505-516
Author(s):  
Monika Stankovská ◽  
Mária Fišerová ◽  
Juraj Gigac ◽  
Elena Opálená
Keyword(s):  
Water Absorption ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Initial Water ◽  
Paper Properties ◽  
High Brightness ◽  
Tissue Paper ◽  
Tensile Index ◽  
Bleached Kraft Pulp ◽  
Eucalyptus Kraft Pulp

The influence of addition of deinked pulps with low and high brightness to bleached eucalyptus and pine kraft pulps on functional tissue paper properties was studied. Deinked pulps with low and high brightness had some different functional properties. Deinked pulp with high brightness has higher bulk, porosity, water absorption after immersion, initial water absorption, bulk softness as well as brightness. On the contrary, the difference in relative bonded area and porosity e between deinked pulps with low and high brightness was moderate. The mixed pulps laboratory pulp sheets from bleached eucalyptus kraft pulp or bleached pine kraft pulp with addition of 20, 40 and 80% of deinked pulp with low brightness or deinked pulp with high brightness were prepared. The addition of the deinked pulp with high or low brightness to bleached kraft pulp leads to increasing of bulk, bulk softness as well as high water absorption after immersion and initial water absorption. The tensile index rapidly decreased by the addition of deinked pulps with high brightness to bleached eucalyptus and pine kraft pulps. Similarly, the addition of deinked pulp with low brightness to bleached pine kraft pulp led to rapid decreasing of tensile index. On contrary, with the addition of deinked pulp with low brightness to eucalyptus kraft pulp, the decreasing of tensile index was less pronounced. Mixed pulp from bleached eucalyptus kraft pulp with a small content of deinked pulp with low brightness with functional properties suitable for production of tissue papers was found as optimal.

Kraft pulp bleaching with a P-stage catalyzed by both bicarbonate and TAED

TAPPI Journal ◽  
2019 ◽  
Vol 18 (7) ◽  
pp. 409-414
Author(s):  
N. DAS ◽  
S.K. BOSE ◽  
R.C. FRANCIS
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Bicarbonate ◽  
Sodium Hydroxide ◽  
Sodium Carbonate ◽  
Kraft Pulp ◽  
Kraft Pulps ◽  
Pulp Bleaching ◽  
Peroxide Bleaching ◽  
Kraft Pulp Bleaching ◽  
Peroxide Activation

Peroxide bleaching of softwood and hardwood (eucalypt) kraft pulps was performed in solutions of sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3), and sodium hydroxide (NaOH). The conventional P stage (hydrogen peroxide + sodium hydroxide; H2O2 + NaOH) was the most effective brightening system without an additional activator. However, peroxide activation by bicarbonate anion (HCO3–) was obvious in all cases where NaHCO3 or Na2CO3 was used. When N,N,N’,N’-tetraacetylethylenediamine (TAED) was added to the bleaching system, Na2CO3 as the alkali source afforded equal or slightly higher bleached brightness compared to NaOH usage for both the softwood and hardwood pulps. This outcome is attributed to simultaneous peroxide activation by HCO3 and TAED. When applied to the eucalypt pulp, the H2O2/Na2CO3/TAED bleaching system also decreased the brightness loss due to thermal reversion.

scholarly journals The manufacture of bleached kraft pulp from persimmon byproducts

BioResources ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 492-504
Author(s):  
Hae Min Jo ◽  
Ji Young Lee ◽  
Su Ho Kim ◽  
Kyung Min Kim
Keyword(s):  
Kraft Pulp ◽  
Raw Materials ◽  
Physical Characteristics ◽  
Cooking Time ◽  
Alkali Concentration ◽  
Kraft Pulps ◽  
Liquid Ratio ◽  
Bleached Kraft Pulp

The authors explored the possibility of using persimmon byproducts as raw materials for obtaining kraft pulps. Various unbleached and bleached kraft pulps via pulping and bleaching processes were prepared. Then, their characteristics were determined and compared with those of commercial kraft pulps. For the highest screened yield of persimmon byproduct unbleached kraft pulps, the optimal pulping conditions were a liquid ratio of 5:1, an active alkali concentration of 25%, a sulfidity of 30%, and a cooking time of 3 h. Furthermore, the authors obtained persimmon byproduct bleached kraft pulps (PB-BKPs) with an ISO brightness of 73% via three-stage bleaching using 3% ClO2, 1.5% NaOH, and 3.5% ClO2. Moreover, PB-BKP prepared under optimal pulping and bleaching conditions had physical characteristics similar to those of commercial mixed-hardwood bleached kraft pulp, but with relatively low ISO brightness. Therefore, as raw materials, persimmon byproducts can be used for manufacturing a bleached kraft pulp.

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