MgSO4 vs. Mg(OH)2 as a cellulose protector in oxygen delignification

Holzforschung ◽  
2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Jean Bouchard ◽  
Jie Wang ◽  
Richard Berry
Keyword(s):  
Calcium Concentration ◽  
Lower Cost ◽  
Iron Concentration ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Major Mechanism ◽  
Carbohydrate Complex ◽  
Magnesium Compound ◽  
Unbleached Pulp

Abstract It has been proposed that magnesium hydroxide can replace magnesium sulfate as a lower cost cellulose protector. This claim has been evaluated based on four commercial unbleached softwood kraft pulps. The selectivity was improved in the presence of soluble MgSO4, but little or no selectivity improvement was obtained when insoluble Mg(OH)2 was applied. It was further observed that in-situ iron concentration in unbleached pulp affects selectivity of oxygen delignification, while in-situ calcium concentration affects efficiency of magnesium protection. The results favor the hypothesis of formation of a Mg-carbohydrate complex as the major mechanism of cellulose protection by magnesium. The application of a soluble magnesium compound is recommended to improve selectivity in oxygen delignification.

Changes in the lignin-carbohydrate complex in softwood kraft pulp during kraft and oxygen delignification

Holzforschung ◽  
2004 ◽  
Vol 58 (6) ◽  
pp. 603-610 ◽  
Author(s):  
Martin Lawoko ◽  
Rickard Berggren ◽  
Fredrik Berthold ◽  
Gunnar Henriksson ◽  
Göran Gellerstedt
Keyword(s):  
Kraft Pulp ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Residual Lignin ◽  
Oxygen Delignification ◽  
Number Range ◽  
Morphological Aspects ◽  
Carbohydrate Complex ◽  
Softwood Kraft Pulp ◽  
Hydrolysis Of

Abstract Three kraft pulps in the kappa number range between 50 and 20 and the same pulps oxygen-delignified to similar lignin contents (kappa approximately 6) were analyzed for lignin-carbohydrate complexes (LCC) by a method based on selective enzymatic hydrolysis of the cellulose, and quantitative fractionation of the LCC. Between 85 and 90% of residual lignin in the unbleached kraft pulp and all residual lignin in the oxygen-delignified pulps were isolated as LCC. Three types of complexes were found; viz., xylan-lignin, glucomannan-lignin-xylan and glucanlignin complexes. After pulping to a high kappa number, most of the residual lignin was linked to xylan. Different delignification rates were observed so that most of the residual lignin was linked to glucomannan when the pulping was extended to a low kappa number. With increasing degree of oxygen delignification, a similar trend in the delignification rates of LCC was observed so that the residual lignin was increasingly linked to glucomannan. Complex LCC network structures seemed to be degraded into simpler structures during delignification. The differences in delignification rates are discussed with reference to the solubility properties and structural differences of LCC, and to morphological aspects of the pulp.

Pulp delignification with oxygen and copper(II)-polyimine complexes

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 377-384 ◽  
Author(s):  
Basile Gueneau ◽  
Nathalie Marlin ◽  
Alain Deronzier ◽  
Dominique Lachenal
Keyword(s):  
Redox Potential ◽  
Kraft Pulp ◽  
Oxygen Activation ◽  
Kraft Lignin ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Mechanical Pulp ◽  
Bleached Pulp ◽  
Carbohydrate Degradation ◽  
Unbleached Pulp

Abstract Ten Cu(II)-polyimine complexes were tested as potential catalysts in oxygen delignification of softwood kraft pulps. The ligands were chosen from the terpyridine and the phenanthroline families, including several neocuproines. One diamine-phenanthrene (daphen) was also investigated. The main purpose was to examine whether the presence of methyl or phenyl substituents would direct the oxidation toward lignin. As a catalyst for comparison, unsubstituted 1,10-phenanthroline was selected, which is known to activate both delignification and carbohydrate degradation during oxygen bleaching of kraft pulp. The variation of ligands was aiming at the complex solubility and redox potential of the parameters. The experiments were performed on a mixture of mechanical pulp and fully bleached kraft pulps, a fully bleached pulp alone, and an industrial unbleached pulp. Concerning the oxygen activation in delignification of kraft pulp, 4,7-diphenyl-1,10-phenanthroline was as good as 1,10-phenanthroline, but appeared to be more selective, which resulted in a higher DPv of cellulose after treatment. This was interpreted by the structural similarities between the ligand and the kraft lignin and by a better stability of the intermediate complex with lignin. Two Cu(II)-phenanthroline derivatives complexes (4,7- and 5,6-dimethyl-1,10-phenanthroline) were also identified as effective oxygen activators for the removal of native lignin.

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

Deep eutectic solvent delignification: Impact of initial lignin

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7301-7310
Author(s):  
Veronika Majová ◽  
Silvia Horanová ◽  
Andrea Škulcová ◽  
Jozef Šima ◽  
Michal Jablonský
Keyword(s):  
Lactic Acid ◽  
Oxalic Acid ◽  
Lignin Content ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Detailed Understanding

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

scholarly journals SEPARATION OF Ca AND Fe METAL ION IN SOURCE WATER BY ADSORPTION COLUMN TECHNIC WITH LOCAL ZEOLITE AND ACTIVE CARBON

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Suyanta Suyanta ◽  
Hanafi Idham Kholid ◽  
Bambang S
Keyword(s):  
Active Carbon ◽  
Calcium Ion ◽  
Metal Ion ◽  
Calcium Concentration ◽  
Flow System ◽  
Iron Concentration ◽  
Source Water ◽  
Adsorption Time ◽  
Adsorption Column ◽  
Column Adsorption

This research aims are to separate of Ca and Fe metal ion in source water, with local zeolite and active carbon by adsorption column technic. Efficiency of separation are control by adsorption time and size of zeolite. Method that used was column adsorption with a flow system in which sample is applied to the filtration tube containing zeolite and active carbon. Initial and final concentrations of the samples were analyzed using Atomic Adsorption Spectrophotometer instrument. The results obtained shows that ability adsorption of zeolite to Ca and Fe metal ion are a good. Zeolite 1 (10 mesh) can reduce iron concentration until 93.98 % and zeolite 2 (5mesh) until 98.88% for 1 – 4 week range time. Whereas reducing of calcium concentration is not good, until 2 week period time adsorption of calcium ion is about 50%. Keywords: adsorption, zeolite, source water

scholarly journals A Novel Lithium Foil Cosmic-Ray Neutron Detector for Measuring Field-Scale Soil Moisture

2021 ◽  
Vol 3 ◽  
Author(s):  
Andres Patrignani ◽  
Tyson E. Ochsner ◽  
Benjamin Montag ◽  
Steven Bellinger
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Atmospheric Pressure ◽  
Lower Cost ◽  
Cosmic Ray ◽  
Absolute Difference ◽  
Atmospheric Conditions ◽  
Volumetric Soil Water Content ◽  
The Mean

During the past decade, cosmic-ray neutron sensing technology has enabled researchers to reveal soil moisture spatial patterns and to estimate landscape-average soil moisture for hydrological and agricultural applications. However, reliance on rare materials such as helium-3 increases the cost of cosmic-ray neutron probes (CRNPs) and limits the adoption of this unique technology beyond the realm of academic research. In this study, we evaluated a novel lower cost CRNP based on moderated ultra-thin lithium-6 foil (Li foil system) technology against a commercially-available CRNP based on BF3 (boron trifluoride, BF-3 system). The study was conducted in a cropped field located in the Konza Prairie Biological Station near Manhattan, Kansas, USA (325 m a.s.l.) from 10 April 2020 to 18 June 2020. During this period the mean atmospheric pressure was 977 kPa, the mean air relative humidity was 70%, and the average volumetric soil water content was 0.277 m3 m−3. Raw fast neutron counts were corrected for atmospheric pressure, atmospheric water vapor, and incoming neutron flux. Calibration of the CRNPs was conducted using four intensive field surveys (n > 120), in combination with continuous observations from an existing array of in situ soil moisture sensors. The time series of uncorrected neutron counts of the Li foil system was highly correlated (r2 = 0.91) to that of the BF-3 system. The Li foil system had an average of 2,250 corrected neutron counts per hour with an uncertainty of 2.25%, values that are specific to the instrument size, detector configuration, and atmospheric conditions. The estimated volumetric water content from the Li foil system had a mean absolute difference of 0.022 m3 m−3 compared to the value from the array of in situ sensors. The new Li foil detector offers a promising lower cost alternative to existing cosmic-ray neutron detection devices used for hectometer-scale soil moisture monitoring.

Ethanol-Enhanced Alkaline Pulping of Arundo donax L. Reed: Influence of Solvent on Pulp Yield and Quality

Holzforschung ◽  
2002 ◽  
Vol 56 (5) ◽  
pp. 507-512 ◽  
Author(s):  
A. A. Shatalov ◽  
H. Pereira
Keyword(s):  
Ethanol Concentration ◽  
Arundo Donax ◽  
Pulp Yield ◽  
Kraft Pulps ◽  
Alkaline Pulping ◽  
Yield And Quality ◽  
Carbohydrate Complex ◽  
Ethanol Addition ◽  
Pulp Strength ◽  
Positive Effect

Summary The effect of solvent on yield and properties of ethanol-alkali pulps from Arundo donax L. was studied. Selectivity of pulping was significantly improved with increase in solvent proportion in the cooking liquor. A rise in ethanol concentration from 20 to 60% (by vol.) increased pulp yield from 44.0 to 48.9%, while decreasing residual lignin from 5.0 to 3.0%. Ethanol addition had a positive effect on preservation of carbohydrate complex against degradation in alkaline medium. Intrinsic viscosity of cellulose was improved up to 35% and xylan content increased from 8.6 to 12.1% with increase in ethanol concentration from 20 to 60%. The preservation of minor non-cellulosic polysaccharides with solvent addition was also observed. The papermaking properties of ethanol-alkali pulps were best for 20% ethanol content. An increase in solvent charge led to a drop in burst, tear and tensile pulp strength. Solvent addition assisted the conversion of glucuronic to hexenuronic acids, whereas the content of HexA in ethanol-alkali pulps of Arundo donax (about 10 μmol/g) was substantially lower than reported for kraft pulps from wood.

Pre-bleaching of kraft acacia pulp

2019 ◽  
Vol 34 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Moinul Haque ◽  
Moumita Nanjiba ◽  
M. Sarwar Jahan ◽  
M. A. Quaiyyum ◽  
M. Zahangir Alam ◽  
...  
Keyword(s):  
Acacia Mangium ◽  
Kappa Number ◽  
Acacia Auriculiformis ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Acid Pretreatment ◽  
Acacia Hybrid ◽  
Pre Treatment ◽  
Hexenuronic Acid ◽  
Peroxyformic Acid

Abstract Kraft pulps from acacia hybrid, Acacia mangium of 8 years old and Acacia auriculiformis of 6, 8 and 10 years old were pre-treated with oxygen, peroxyformic acid and acid treatment prior to bleaching. The kappa number reduction was 52–63 % by oxygen delignification, 31–35 % by peroxyformic acid (PFA) pre-treatment and 11–13 % by acid pre-treatment. Oxygen delignified pulp required less chlorine dioxide charge to reach target brightness. At the consumption of 30 kg ClO2/ton of pulp, the pulp brightness reached to 65–71 % for the untreated pulp, 81–85 % for the oxygen delignified pulp, 81–82 % for the PFA treatment and 79–80 % for acid pre-treated pulp. COD load in bleached effluent was much lower in oxygen delignified pulp. Cold alkali extraction of unbleached and oxygen delignified pulps was also carried out with varying alkali charge to remove hexenuronic acid (HexA) from the pulp. Xylan removal from the pulp was insignificant and resulted in no removal of HexA. Acid pretreatment removed 55.7 % to 17.8 % HexA from acacia hybrid, 57.5 % to 16.3 % from A. auriculiformis of 10 years and 58.6 % to 20.1 % from A. auriculiformis of 6 years old, resulting in improved final pulp brightness.

scholarly journals Regulation of cytosolic free calcium concentration by intrasynaptic mitochondria.

1992 ◽  
Vol 3 (2) ◽  
pp. 235-248 ◽  
Author(s):  
A Martínez-Serrano ◽  
J Satrústegui
Keyword(s):  
Calcium Concentration ◽  
Adenine Nucleotides ◽  
Free Calcium ◽  
Nerve Terminals ◽  
Cytosolic Free Calcium ◽  
Free Calcium Concentration ◽  
Cytosolic Free Calcium Concentration ◽  
Presynaptic Nerve Terminals

By the use of digitonin permeabilized presynaptic nerve terminals (synaptosomes), we have found that intrasynaptic mitochondria, when studied "in situ," i.e., surrounded by their cytosolic environment, are able to buffer calcium in a range of calcium concentrations close to those usually present in the cytosol of resting synaptosomes. Adenine nucleotides and polyamines, which are usually lost during isolation of mitochondria, greatly improve the calcium-sequestering activity of mitochondria in permeabilized synaptosomes. The hypothesis that the mitochondria contributes to calcium homeostasis at low resting cytosolic free calcium concentration ([Ca2+]i) in synaptosomes has been tested; it has been found that in fact this is the case. Intrasynaptic mitochondria actively accumulates calcium at [Ca2+]i around 10(-7) M, and this activity is necessary for the regulation of [Ca2+]i. When compared with other membrane-limited calcium pools, it was found that depending on external concentration the calcium pool mobilized from mitochondria is similar or even greater than the IP3- or caffeine-sensitive calcium pools. In summary, the results presented argue in favor of a more prominent role of mitochondria in regulating [Ca2+]i in presynaptic nerve terminals, a role that should be reconsidered for other cellular types in light of the present evidence.

Bleaching kraft pulps with in-situ generated dioxiranes

1995 ◽  
Vol 34 (1) ◽  
pp. 400-403 ◽  
Author(s):  
Daphne Santiago ◽  
Augusto Rodriguez ◽  
John Szwec ◽  
Alfons L. Baumstark ◽  
Arthur J. Ragauskas
Keyword(s):  
Kraft Pulps
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