scholarly journals Improving the efficiency of hydrogen peroxide bleaching of chemimechanical pulp by continuous replenishment of bleaching chemicals

TAPPI Journal ◽  
2017 ◽  
Vol 16 (06) ◽  
pp. 331-339
Author(s):  
XIANGI SUN ◽  
QINGXI HOU ◽  
BINGXU ZHANG ◽  
GUANTING ZHAO
Keyword(s):  
Hydrogen Peroxide ◽  
Bleaching Process ◽  
Bleaching Efficiency ◽  
Peroxide Bleaching ◽  
Total Alkali ◽  
Chemical Solutions ◽  
High Consistency

Hydrogen peroxide (H2O2) is commonly used to bleach chemimechanical pulp. A decrease in the concentrations of the bleaching reagents throughout the bleaching process results in low bleaching efficiencies. In this study, chemical solutions were continuously added into the pulp slurry during the bleaching process to maintain constant concentrations of H2O2 and total alkali in the bleaching system to improve bleaching efficiency. The results showed that when the H2O2 and total alkali concentrations were maintained at 4.5 g/L and 0.79 g/L, respectively, for 50 min, the bleaching efficiency reached 16.79 (Δ% ISO brightness/Δ% H2O2 consumed [on ovendry pulp]), which was significantly higher than 7.38 obtained by using the high-consistency bleaching method. The results confirmed that continuous replenishment of chemical solutions into the bleaching system to maintain the constant chemical concentrations improved the efficiency of H2O2 bleaching of the chemimechanical pulp.

scholarly journals Bleaching Process Investigation of Tunisian Dromedary Hair

ISRN Textiles ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
T. Harizi ◽  
S. Dhouib ◽  
S. Msahli ◽  
F. Sakli
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Adverse Effects ◽  
Oxalic Acid ◽  
Review Of The Literature ◽  
Bleaching Process ◽  
Bleaching Efficiency

Successful bleaching of pigmented fibres was, generally, evaluated by a maximum whiteness, a minimum yellowness, and less damage to the bleached fibers. A review of the literature reveals that many studies on pigmented fibre bleaching are concerned with improving the whiteness and mechanical properties of bleached fibres. In this study, we investigate the effects of the hydrogen peroxide concentration, bleaching time, and clarification bath on the bleaching efficiency of Tunisian dromedary hair. It was showed that 30 min bleaching time gives better result in term of whiteness. However, an increased bleaching time gives an excessive damage to the bleached fibers. Further, the damage incurred by the dromedary hair was more important than that for wool, as is shown by the tenacity results. We found that oxalic acid, which is used for rinsing dromedary hair (after bleaching), provides improved results in term of whiteness obtained with bleaching. Certainly, oxalic acid made it possible to remove the maximum of iron remaining on fibre after bleaching. Bleaching methods demonstrate the excessive damage incurred by the fibre when using hydrogen peroxide particularly with raise concentration. This damage leads to adverse effects on the tenacity fibre.

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.

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.

New evidence for the role of the borohydride pretreatment on the hydrogen peroxide bleaching of kraft pulp

RSC Advances ◽  
2015 ◽  
Vol 5 (119) ◽  
pp. 98067-98074 ◽  
Author(s):  
Jing Li ◽  
Huichao Hu ◽  
Yanting Song ◽  
Xin-Sheng Chai
Keyword(s):  
Hydrogen Peroxide ◽  
Kraft Pulp ◽  
Carbonyl Groups ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Chemical Pulps ◽  
New Evidence ◽  
Lignin Structure

New evidences for the role of borohydride pretreatment in hydrogen peroxide bleaching process of eucalyptus chemical pulps were provided, i.e., suppressing the catalysis effect of Fe(iii), decreasing carbonyl groups, and constituent lignin structure.

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