scholarly journals Improving hydrogen peroxide bleaching of aspen CTMP by using aqueous alcohol media

BioResources ◽  
2011 ◽  
Vol 6 (4) ◽  
pp. 4005-4011
Keyword(s):  
Hydrogen Peroxide ◽  
Pulp Yield ◽  
Aqueous Alcohol ◽  
Laboratory Studies ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Bleaching Procedure ◽  
Mechanical Pulps

Preliminary tests of a new hydrogen peroxide bleaching procedure for mechanical pulps were performed in a bleaching medium comprised of water and an alcohol, which is characterized by good miscibility with water, poor solvency for hemicelluloses, and good solvency for lignin. As compared with a conventional bleaching method, this modified process is aimed at reducing the removal of hemicelluloses while moderately increasing the dissolution of lignin. Results showed that an aspen CTMP pulp can be bleached to a target brightness with less bleaching chemicals and/or with a higher pulp yield. The laboratory studies demonstrate that this new bleaching process offers substantially enhanced efficiency and selectivity over the conventional peroxide bleaching. Overall, the brightness increased by about 5 ISO units for a given peroxide consumption and the yield increased by 2 to 3 percent at the same target brightness.

Study on Magnesium Hydroxide-Based Hydrogen Peroxide Bleaching Process of Nigra poplar CTMP

2011 ◽  
Vol 233-235 ◽  
pp. 1328-1331 ◽  
Author(s):  
Qiang Zhao ◽  
De Zhi Sun ◽  
Ming Yang Zhang ◽  
Su Min Kang
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Magnesium Hydroxide ◽  
High Yield ◽  
Pulp Yield ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Bleaching Condition ◽  
Pulp Consistency

The Mg(OH)2-based peroxide bleaching process of Nigra poplar CTMP pulp was confirmed. The optimal bleaching condition were as follows: 4% H2O2,1% Mg(OH)2, 15% pulp consistency, the reaction temperature was 80°C and the suitable reaction time was 2 hours. The Mg(OH)2-based bleaching process shows significant benefits over sodium hydroxide process. In contrast, magnesium hydroxide bleaching generates higher pulp yield and lower effluent COD at the same chemical dosage. The study shows peroxide bleaching of CTMP pulp with magnesium hydroxide as alkali source is to be an option for the high-yield pulp bleaching.

Modified hydrogen peroxide bleaching of bamboo chemo-mechanical pulp using aqueous alcohol media

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 870-881
Author(s):  
Fangmin Liang ◽  
Guigan Fang ◽  
Jian Jiao ◽  
Yongjun Deng ◽  
Shanming Han ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Conventional Method ◽  
Value Added ◽  
Aqueous Alcohol ◽  
Mechanical Pulp ◽  
Bleaching Efficiency ◽  
Peroxide Bleaching ◽  
Bleaching Procedure ◽  
Usage Level

The brightness of bleached bamboo chemo-mechanical pulp (CMP) is often too low to be used as a furnish in value-added paper products. In this study, preliminary optimization of various parameters of a modified hydrogen peroxide (H2O2) bleaching procedure for bamboo CMP pulps was performed using the inclusion of ethanol in the bleaching medium (IEBM). Compared with a conventional bleaching method, this modified process is aimed at improving bleaching efficiency and brightness ceiling of bamboo CMP with the proper usage of chemicals. The CMP was bleached to a brightness of 74.2% ISO at the usage level of 12% H2O2, which shows it increased by 7.4% ISO compared with the conventional method. For a brightness target of 72.0% ISO, bleaching with the IEBM method reduced the H2O2 consumption by approximately 60%. In addition, a higher activation energy of H2O2 for the IEBM method was calculated to be 23.3 kJ/mol, which was increased by 3.3 kJ/mol compared with the conventional method.

scholarly journals A comparative analysis of in-office vital 6% hydrogen peroxide activated charcoal tooth whitening treatment enhanced with an 810nm diode laser, compared to 35% hydrogen peroxide bleaching

2021 ◽  
Vol 76 (2) ◽  
pp. 64-71
Author(s):  
Shabeer I Hassim ◽  
Tufayl A Muslim
Keyword(s):  
Hydrogen Peroxide ◽  
Diode Laser ◽  
Activated Charcoal ◽  
Research Question ◽  
Treatment Protocol ◽  
Primary Data ◽  
Absorption Enhancement ◽  
Significance Level ◽  
Peroxide Bleaching ◽  
Bleaching Procedure

Laser dental bleaching is considered to be a contemporary approach to enhancing the in-office power bleaching procedure. Objective Investigate if laser enhanced 6% Hydrogen Peroxide (HP) solution is equivalent to 35% HP solution over a two-visit power bleaching treatment protocol. In a randomised double-blinded clinical trial, 43 patients were assigned to a group that received either the laser-enhanced 6% Hydrogen Peroxide (n=21) treatment, or the standard 35% Hydrogen Peroxide (n=22) treatment, over two visits, with a one-week interval. Activated charcoal HP paste was prepared for both groups. The laser enhanced 6% HP group received a dosage of 90 J/cm² per bleaching cycle using 810nm diode laser. Tooth colour was measured at the beginning and end of each session registering parameters L*, a* and b*, and tooth sensitivity. The calculated difference between these Parameters, ∆E, was the primary data focus. The mean ∆E over the treatment duration was used to answer the research question by a t-test to evaluate group differences at 5% significance level. The analysis revealed that the null hypothesis could not be rejected and the results were inconclusive. The observations expound the idea of an absorption enhancement mechanism, rather than a free radical activation, as the technique for improving bleaching outcomes.

Review: Using magnesium hydroxide as the alkali source for peroxide bleaching of mechanical pulps - process chemistry and industrial implementation

2010 ◽  
Vol 25 (2) ◽  
pp. 170-177 ◽  
Author(s):  
Yonghao Ni ◽  
Zhibin He
Keyword(s):  
Sodium Hydroxide ◽  
Magnesium Hydroxide ◽  
Paper Industry ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Industrial Implementation ◽  
Process Chemistry ◽  
Peroxide Decomposition ◽  
Mechanical Pulps ◽  
Pulp Properties

Abstract Magnesium hydroxide, which is a weak alkali, can be used as the alkali source for peroxide bleaching of mechanical pulps. This magnesium hydroxide-based peroxide bleaching process has been commercialized in the paper industry. In this paper, we review the literature results regarding the process chemistry of the Mg(OH)2-based peroxide bleaching process, including the kinetics, peroxide decomposition, anionic trash/COD/oxalate formation, the effect on pulp properties. The benefits associated with the Mg(OH)2- based peroxide bleaching process are discussed. We also discuss the mill implementation of the Mg(OH)2- based peroxide bleaching process in the pulp and paper industry. A case is presented where magnesium hydroxide completely replaces sodium hydroxide as the alkali source. A partial magnesium substitution for sodium hydroxide can also be an option.

scholarly journals Effect of hydrogen peroxide application on color and surface roughness of two restorative materials

2017 ◽  
Vol 15 (3) ◽  
pp. 185
Author(s):  
Dilcele Silva Moreira Dziedzic ◽  
Lucia Helena Ramos da Silva ◽  
Bruna Luiza do Nascimento ◽  
Marina Samara Baechtold ◽  
Gisele Maria Correr ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Repeated Measures ◽  
Glass Ionomer Cement ◽  
Color Variation ◽  
Glass Ionomer ◽  
Peroxide Bleaching ◽  
Bleaching Procedure ◽  
Resin Modified Glass Ionomer ◽  
Ionomer Cement

Aim: This study investigated the effect of an in-office bleaching technique on lightness, color and surface roughness of two commercially available materials: a resin-modified glass-ionomer cement and a nanohybrid resin composite. Methods: Twelve disk-shaped specimens were prepared with both materials. The samples were bleached with 35% hydrogen peroxide. Bleaching was tested initially onto a smooth surface and later onto a polished one of the same specimens. The effect of the treatments on lightness and color was verified with a spectrophotometer. Surface roughness was measured with a digital surface roughness tester. The data were statistically analyzed by repeated measures ANOVA and post hoc Tukey’s test (alpha = 0.05). Results: Significant variation in lightness and color was observed on the resin-modified glass-ionomer cement after the first bleaching procedure. Roughness increased significantly only after polishing the resin-modified glass-ionomer cement surface. Composite color variation was evident in the last observation period, but roughness and lightness variation due to bleaching and polishing was not significant. Conclusion: The bleaching treatment caused significant color alterations on the materials tested. This study observed that the application of in-office bleaching onto the glass-ionomer cement promoted clinically observable color alteration, and polishing after bleaching is contraindicated for this material.

scholarly journals Pomegranate (Punica granatum L.) gel extract as an antioxidant on the shear bond strength of a resin composite post-bleaching application with 40% hydrogen peroxide

2021 ◽  
Vol 54 (2) ◽  
pp. 87
Author(s):  
Indes Rosmalisa Suratno ◽  
Irfan Dwiandhono ◽  
Ryana Budi Purnama
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Composite Resin ◽  
Resin Composite ◽  
Punica Granatum ◽  
Negative Control ◽  
Peroxide Bleaching ◽  
Bleaching Procedure

Background: Tooth discoloration can be treated with tooth bleaching. Bleaching using 40% hydrogen peroxide can reduce the shear bond strength of resin composite because there are free radicals on the tooth surface, so it can delay the restoration. The application of antioxidants can eliminate free radicals after the bleaching procedure and increase the shear bond strength of the composite resin. The common antioxidants are ascorbic acid and natural ingredients, such as pomegranate (Punica granatum L.). Purpose: To determine the effect of pomegranate extract gel on the shear bond strength of composite resin after 40% hydrogen peroxide bleaching application. Methods: This research used 32 maxillary first premolars that were divided into four groups. The samples were bleached, then the labial was prepared and antioxidant gel was applied: group P1 pomegranate gel extract of 5%, group P2 pomegranate gel extract of 10%, group K1 positive control ascorbic acid gel of 10% and group K2 as the negative control. The samples were restored with a nanohybrid composite resin. The shear bond strength was tested using a universal testing machine. The data were tested using a one-way ANOVA followed by a post-hoc LSD test. Results: The pomegranate gel extract increased the shear bond strength of the composite resin after the bleaching procedure of 40% hydrogen peroxide compared with the ascorbic acid gel group and the negative control group. The one-way ANOVA test showed a significant difference (p<0.05). The post-hoc LSD test showed significant differences between the treatment and negative control groups (p<0.05). Conclusion: The pomegranate gel extract as an antioxidant increased the shear bond strength of the composite resin restoration after the 40% hydrogen peroxide bleaching application.

Hydrogen Peroxide Bleaching to Wine Corks with a Novel Catalyst

2013 ◽  
Vol 734-737 ◽  
pp. 2282-2286 ◽  
Author(s):  
Li Liu ◽  
Shu Ling Cui
Keyword(s):  
Hydrogen Peroxide ◽  
Cork Stopper ◽  
Capillary Effect ◽  
Sewage Disposal ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Novel Catalyst

A novel catalyst CF-R for hydrogen peroxide bleaching to wine cork stopper was chosen to substitute the traditional imported item, and the corresponding bleaching process was studied. The influence of catalyst CF-R dosage, H2O2 concentration, bleaching temperature and time on cork whiteness and capillary effect were discussed. The optimized bleaching process for wine corks was obtained as follows: H2O2 concentration 14%, catalyst CF-R dosage 80g/L, bleaching temperature 70°Cand bleaching time 60 min. Comparing with the expensive imported catalyst, the amount of catalyst CF-R is greatly decreased, as is significant for not only cutting down the expenditure of chemicals, but also minimizing the burden on bleaching sewage disposal.

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