scholarly journals Kraft Pulp Bleaching with Hydrogen Peroxide in a Batch Reactor.

1995 ◽  
Vol 21 (5) ◽  
pp. 866-870
Author(s):  
Toshitaka Funazukuri ◽  
Hiromasa Takahashi ◽  
Ken Miyajima ◽  
Noriaki Wakao
Keyword(s):  
Hydrogen Peroxide ◽  
Kraft Pulp ◽  
Batch Reactor ◽  
Pulp Bleaching ◽  
Kraft Pulp Bleaching

Oxidized Derivatives of Lipophilic Extractives Formed during Hardwood Kraft Pulp Bleaching

Holzforschung ◽  
2003 ◽  
Vol 57 (5) ◽  
pp. 503-512 ◽  
Author(s):  
C. S. R. Freire ◽  
A. J. D. Silvestre ◽  
C. Pascoal Neto
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Structural Changes ◽  
Oxidation Products ◽  
Pulp Bleaching ◽  
Peroxide Bleaching ◽  
Kraft Pulp Bleaching ◽  
First Time ◽  
Derivatives Of

Summary The structural changes of E. globulus wood extractives during bleaching with chlorine dioxide (D), oxygen (O), ozone (Z) and hydrogen peroxide (P) were studied. The detailed characterisation of the extractive derivatives detected in the partially bleached D, O, P and Z pulps was achieved by performing reactions of pure reference compounds with the different bleaching agents. The results show that the unsaturated sterols and fatty acids are extensively degraded during chlorine dioxide and ozone bleaching and only partially degraded during oxygen and hydrogen peroxide bleaching. The corresponding saturated extractives as well as the long chain aliphatic alcohols and ω-hydroxyfatty acids were stable during bleaching. The main oxidation products of β-sitosterol and oleic and linoleic acids, including one chlorinated derivative of linoleic acid, were identified here for the first time in E. globulus bleached pulps and bleaching filtrates.

Application of a Catalyst in Peroxide Bleaching of Eucalyptus Kraft Pulp

Holzforschung ◽  
2000 ◽  
Vol 54 (4) ◽  
pp. 407-412 ◽  
Author(s):  
L. Kühne ◽  
J. Odermatt ◽  
T. Wachter
Keyword(s):  
Hydrogen Peroxide ◽  
Kraft Pulp ◽  
Pulp Bleaching ◽  
Selective Catalyst ◽  
Peroxide Bleaching ◽  
Softwood Pulp ◽  
Kraft Pulp Bleaching ◽  
Eucalyptus Kraft Pulp ◽  
Softwood Kraft Pulp

Summary A binuclear [Mn(III)Mn(IV)(μ-O)2(μ-CH3COO)L](ClO4−)2 complex with L = 1,2 Bis-(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)-ethane, described as a selective catalyst in hydrogen peroxide bleaching of softwood pulps, was tested in hardwood kraft pulp bleaching. The catalyst application gave rise to a higher consumption of peroxide which resulted in higher pulp brightness. The delignification improvement caused by the catalyst was shown to be much lower compared to catalysed peroxide bleaching of softwood kraft pulp. In contrast to the results of softwood pulp bleaching no selectivity improvements could be found when using the catalyst in bleaching of eucalyptus kraft pulp.

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.

Formation of organochlorine compounds in kraft pulp bleaching processes

Chemosphere ◽  
1996 ◽  
Vol 33 (12) ◽  
pp. 2431-2440 ◽  
Author(s):  
S. Juuti ◽  
T. Vartiainen ◽  
J. Ruuskanen
Keyword(s):  
Kraft Pulp ◽  
Organochlorine Compounds ◽  
Pulp Bleaching ◽  
Kraft Pulp Bleaching

Treatability of kraft pulp bleaching wastewater by biochemical and photocatalytic oxidation

1999 ◽  
Vol 40 (1) ◽  
pp. 281-288 ◽  
Author(s):  
Işıl Akmehmet Balcıoǧlu ◽  
Ferhan Çeçen
Keyword(s):  
Biological Treatment ◽  
Kraft Pulp ◽  
Photocatalytic Oxidation ◽  
Treated Wastewater ◽  
Oxidation Reactions ◽  
Pulp Bleaching ◽  
Kraft Pulp Bleaching ◽  
Activated Sludge Reactor ◽  
Sulfate Pulp ◽  
Biological Treatability

In this study the biological treatability and TiO2 photocatalyzed oxidation characteristics of sulfate pulp bleaching effluents were investigated. The original wastes had a low biodegradability as determined by BOD5/COD ratios. Biological treatment was conducted in a batch activated sludge reactor. The non-biodegradable fraction amounted to 60% of the initial COD and compounds specific to these wastes were not removed during biotreatment. In order to enhance the biodegradability of these wastes, mixed raw effluent, C/E-H stage effluent, D/E-D stage effluent and biologically pretreated wastes were subjected to TiO2 photocatalyzed oxidation. Photocatalytic oxidation led to an increase in the BOD5/COD ratio of D/E-H stage raw and biologically treated wastewater, while chloride formation was observed in both cases in a five-hour reaction period in the presence of 1g 1−1 TiO2 and 15×10−3 M H2O2 at pH=6.5. The specific absorption values (A272nm/CODs, A254nm/CODs, A346nm/CODs, A436nm/CODs) exhibited parallel decreases during photocatalytic oxidation which indicate that oxidation reactions were nonspecific with respect to the organics present in these wastes. As a conclusion it can be suggested that biological treatment should be placed before the photocatalytic oxidation method. Even in this scheme, the application of photocatalytic oxidation could only then be favored when the COD and chloride concentrations in the wastewater were below certain values or when wastewater was diluted.

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