Peroxymonosulfuric Acid Treatment as an Alternative to Ozone for Totally Chlorine-free and Elementary Chlorine-free Bleaching of Hardwoods Prehydrolysis-kraft Pulp

Abstract To clarify the influence of prehydrolysis on fiber characteristics, Scots pine (Pinus sylvestris L.) wood chips were subjected to pressurized hot-water and dilute-acid prehydrolysis (0.5% H2SO4) prior to kraft pulping to partially remove hemicelluloses as hydrolyzate. After the prehydrolysis, the wood chips were submitted to kraft pulping and the pulp was fully bleached in oxygen (O), chlorine dioxide (D), alkaline extraction (E) and chlorine dioxide (D)-sequence. Measurements with an automated optical fiber analyzer showed that prehydrolysis prior to kraft pulping caused significant changes in the fiber dimensions and morphology of the final bleached pulp. Especially, a decrease in fiber width and an increase in fiber deformations were observed compared to a reference kraft pulp. The scanning electron microscopy of handsheets supported the morphology analyses and revealed alterations also in the fiber ultrastructure. The changes in both chemical and physical fiber characteristics require attention when considering the correct processing and end-use of prehydrolysis-kraft pulp fibers.

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Enzymes improve ECF bleaching of pulp

BioResources ◽

10.15376/biores.1.1.34-44 ◽

2006 ◽

Vol 1 (1) ◽

pp. 34-44 ◽

Cited By ~ 4

Keyword(s):

Chlorine Dioxide ◽

Acid Treatment ◽

Kraft Pulp ◽

Elemental Chlorine ◽

Eucalyptus Kraft Pulp ◽

Mediator System ◽

Pulp Properties ◽

Laccase Enzyme ◽

Ecf Bleaching ◽

Appreciable Reduction

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. A n appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction in chlorine dioxide consumption was obtained when the same laccase treated pulp was subjected to an acid treatment after the extraction stage followed by the DE P D sequence. Elemental-chlorine free bleaching was also performed using the xylanase-laccase treated pulp. Xylanase treatment was incorporated to the laccase mediator system in the elemental-chlorine free bleaching both sequentially and simultaneously. The bleaching sequence DE P D followed and in both the cases, the reduction in chlorine dioxide consumption was greater in comparison to the control. The chlorine dioxide consumption was reduced further when xylanase-laccase treated pulp was given an additional acid treatment. The final pulp properties of the treated pulps were comparable to the control pulp.

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Effect of UV radiation on the carbonyl distribution in different pulps

Holzforschung ◽

10.1515/hf.2004.113 ◽

2004 ◽

Vol 58 (6) ◽

pp. 597-602 ◽

Cited By ~ 13

Author(s):

Antje Potthast ◽

Sonja Schiehser ◽

Thomas Rosenau ◽

Herbert Sixta ◽

Paul Kosma

Keyword(s):

Molecular Weight ◽

Molecular Weight Distribution ◽

Weight Distribution ◽

Kraft Pulp ◽

Cellulose Degradation ◽

Minor Effect ◽

Carbonyl Groups ◽

Eucalyptus Kraft Pulp ◽

Prehydrolysis Kraft ◽

Ccoa Method

Abstract The effect of UV irradiation on unbleached and TCF-bleached dissolving pulp samples of different provenience, a beech sulphite and an eucalyptus prehydrolysis kraft pulp, has been analyzed according to the CCOA method, evaluating the changes in the molecular weight distribution, the total number of carbonyl groups and the carbonyl group profiles of each pulp. In the case of TCF bleached material, slightly more carbonyl groups were introduced into the kraft pulp as compared to the sulfite pulp. Cellulose degradation was relatively low in both pulps. In the case of unbleached sulfite pulps, the residual lignin had only a minor effect on the molecular weight distribution and the oxidation state of the cellulose, whereas for eucalyptus kraft pulp a pronounced introduction of carbonyl groups accompanied by severe degradation of cellulose was observed. The presence of hemicelluloses governed the photochemical behavior and the carbonyl profiles of the low molecular weight region of the cellulose.

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Fasciaton of Pectate Elementary Fibrils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070746 ◽

1973 ◽

Vol 31 ◽

pp. 60-61

Author(s):

George F. Leeper

Keyword(s):

Acid Treatment ◽

Carbon Film ◽

Final Concentration ◽

Cellulose Microfibrils ◽

Pectic Acid ◽

Elementary Fibrils

Polysaccharide elementary fibrils are usually fasciated into microfibrils of from one hundred to a few hundred Angstroms wide. Cellulose microfibrils when subjected to acid treatment dissociate into component elementary fibrils. For pectic acid it was observed that variations in pH could cause a change in the fasciation of the elementary fibrils.Solutions of purified pectic acid and sodium phosphotungtate were adjusted to various pH levels with NaOH or HCl and diluted to give a final concentration of 0.5 and 1% for the polysaccharide and negative stains respectively. Micrographs were made of the samples after drying on a carbon film covered grid. The average number of elementary fibrils was determined by counting the number of elementary fibrils in each fascicle intersected by lines drawn across the micrograph.

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Increased expression of FABP1 and cFLIPL by free fatty acid treatment is associated with reduced death-receptor mediated apoptosis in human primary hepatocytes

Zeitschrift für Gastroenterologie ◽

10.1055/s-0029-1246457 ◽

2010 ◽

Vol 48 (01) ◽

Author(s):

S Sydor ◽

P Kocabayoglu ◽

J Treckmann ◽

G Kaiser ◽

G Gerken ◽

...

Keyword(s):

Fatty Acid ◽

Free Fatty Acid ◽

Acid Treatment ◽

Death Receptor ◽

Primary Hepatocytes ◽

Fatty Acid Treatment ◽

Human Primary Hepatocytes

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Does anti-acid treatment influence disease progression in SSc-ILD? Data form the German SSc-network

10.1055/s-0039-3403181 ◽

2020 ◽

Author(s):

M Kreuter ◽

F Bonella ◽

N Blank ◽

E Siegert ◽

J Henes ◽

...

Keyword(s):

Disease Progression ◽

Acid Treatment ◽

Data Form

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Effect of valproic acid treatment on body composition, leptin and soluble leptin receptor in epileptic children

Neuropediatrics ◽

10.1055/s-2006-974057 ◽

2006 ◽

Vol 37 (06) ◽

Author(s):

M Rauchenzauner ◽

E Haberlandt ◽

S Scholl-Bürgi ◽

D Karall ◽

E Schönherr ◽

...

Keyword(s):

Valproic Acid ◽

Body Composition ◽

Acid Treatment ◽

Leptin Receptor ◽

Soluble Leptin Receptor ◽

Epileptic Children

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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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