Effects of Magnesium-Based Alkali on the Dissolved and Colloidal Substances in the Alkaline Peroxide Bleaching of Poplar CTMP

2014 ◽  
Vol 53 (8) ◽  
pp. 2897-2902 ◽  
Author(s):  
Wei Liu ◽  
Song Han ◽  
Ningpan Xu ◽  
Qingxi Hou ◽  
Longsheng Xu
Keyword(s):  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Dissolved And Colloidal Substances

Relationship between dissolution of fiber materials and development of pulp strength in alkaline peroxide bleaching of mechanical pulp

Holzforschung ◽  
2004 ◽  
Vol 58 (4) ◽  
pp. 369-375 ◽  
Author(s):  
G.X. Pan
Keyword(s):  
Carboxylic Acid ◽  
Acid Group ◽  
Strength Properties ◽  
Strength Development ◽  
Mechanical Pulp ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Bonding Properties ◽  
Pulp Strength ◽  
Fiber Materials

Abstract This study elucidates the relationship between the dissolution of pulp components and the development of fiber bonding properties in alkaline peroxide bleaching of aspen mechanical pulp. In general, bleaching reactions cause the removal of pulp substances from the fibers, which in turn improves pulp strength properties. Nonetheless, alkaline hydrolysis is particularly important to the development of strength because this reaction mechanism plays a key role in imparting additional carboxylic acid groups onto the fibers. The strong correlation between fiber carboxylic acid group concentration and the amount of anionic dissolved substances makes it possible for us to predict the strength properties of bleached pulps by estimating the anionicity of bleaching filtrates using analytical methods such as cationic demand. The paper also provides insights into the importance of the alkalinity in peroxide bleaching to the dissolution of pulp materials and the strength development.

Analisis kinetika dengan hidrogen peroksida

2018 ◽  
Vol 6 (3) ◽  
pp. 657
Author(s):  
Ahmad M Fuadi ◽  
B. Sediawan Wahyudi ◽  
Suryo P. Rochmadi
Keyword(s):  
New Technologies ◽  
Environmental Concern ◽  
Process Condition ◽  
Solution Viscosity ◽  
Alkaline Condition ◽  
Pulp Bleaching ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Plastic Bag ◽  
Stage Process

As the result of increasing environmental concern, new technologies for bleaching pulps have been developed. Chlorine containing bleaching agents has been replaced by more environmentally benign chemical, such as H2O2. This paper proposes mechanism of alkaline peroxide bleaching in order to get better understanding of the process mechanism. Bleaching mechanism is started by very fast mass transfer, followed by ion HOO' formation. This ion then reacts with lignin which leads to delignification. Before bleaching by H2O2 in alkaline condition, the pulp bleaching is preceded by chelating stage process. As much as 20 gram of dry pulp is added with 2.5% H2O2, NaOH and aquadest until 10% consistency is obtained and mixed completely and then the solution is put in to plastic bag. It is then heated in water bath at 70ºC at various time and concentration of NaOH. When the process condition is reached, residual of H2O2 brightness, kappa number and pulp solution viscosity are determined. The model is examined by comparison between the concentration residual of H2O2 and of lignin from experimental data and calculation result of mathematical model. The result shows that the proposed mechanism can well represent the bleaching process at 70ºCKeywords: Bleaching, Hydrogen Peroxide, Kinetic AbstrakMeningkatnya perhatian terhadap lingkungan, telah memicu pengembangan teknologi pada pemutihan pulp. Senyawa pemutih pulp yang mengandung klorin digantikan dengan senyawa yang ramah lingkungan, antara lain H2O2. Tulisan ini mengusulkan mekanisme yang terjadi pada proses bleaching dengan menggunakan H2O2 dalam suasana basa. Mekanisme bleaching dimulai dengan transfer masayang berlangsung sang at cepat, kemudian diikuti dengan pembentukan ion HOO. Ion ini kemudian bereaksi dengan lignin, sehingga terjadi delignifikasi. Proses bleaching dilakukan dengan H2O2 pada suasana basa yang didahului dengan proses chelating stage. Sebanyak 20 gram pulp kering ditambah dengan 2,5% H2O2, NaOH dan aquades hingga mencapai konsistensi 10%, dicampur sampai homogen kemudian dimasukkan dalam kantung plastik lalu dipanaskan di dalam water bathpada suhu 70ºC pada berbagai waktu dan kadar NaOH. Setelah kondisi operasi dicapai, dilakukan analisa sisa H2O2, derajat putih, bilangan kappa serta viskositas larutan pulp.  Uji ketepatan model yang diusulkan dilakukan dengan membandingkan antara data sisa H2O2 dan sisa kandungan lignin yang diperoleh dari percobaan dengan perhitungan yang diperoleh dari penyelesaian model matematiknya. Hasilnya menunjukkan bahwa mekanisme yang diajukan bisa mewakili proses bleaching yang dijalankan pada suhu 70ºC.Kata kunci:  Bleaching, Hidrogen Peroksida, Kinetika

Changes of anionic groups in alkaline peroxide-impregnated aspen chemithermomechanical pulp during subsequent alkaline peroxide bleaching

2012 ◽  
Vol 88 (3) ◽  
pp. 1041-1046 ◽  
Author(s):  
Zongquan Li ◽  
Ying Qin ◽  
Menghua Qin ◽  
Na Liu ◽  
Qinghua Xu ◽  
...  
Keyword(s):  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Anionic Groups

scholarly journals Use of TOF-SIMS for the analysis of surface metals in H2O2-bleached lignocellulosic fibers

2001 ◽  
Vol 73 (12) ◽  
pp. 2047-2058 ◽  
Author(s):  
Douglas G. Mancosky ◽  
Lucian A. Lucia
Keyword(s):  
Hydrogen Peroxide ◽  
Inductively Coupled Plasma ◽  
Secondary Ion Mass Spectrometry ◽  
Black Spruce ◽  
Fiber Strength ◽  
Cellulose Degradation ◽  
Fiber Surface ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Tof Sims

Oxidation of cellulose, caused by metal-catalyzed hydrogen peroxide decomposition, is one of the main potential reactions that can occur during the alkaline peroxide bleaching of pulp. This oxidation decreases the individual fiber strength and thus the sheet strength. The bleaching reaction should be controlled to limit cellulose degradation. The goal of this project was to characterize the fiber surface metal distribution using time-of-flight secondary ion mass spectrometry (TOF-SIMS) on laboratory-generated hydrogen peroxide-bleached pulps. For this study, a single black spruce was chosen and kraft pulped. Peroxide bleaching was conducted via benchtop polyethylene bag bleaching in a temperature-controlled waterbath. The overall metals content was determined using inductively coupled plasma (ICP), whereas the surface metals were determined with TOF-SIMS. Many fundamental approaches to study metal identity and content in fibers have been undertaken, including ICP, electron spectroscopy for chemical analysis (ESCA), X-ray fluorescence, and UV­vis. None of these methods can provide the localized density distribution and metal-mapping ability that is available through TOF-SIMS. It has spectacular imaging capabilities that were exploited for evaluating metals on the fiber sheets used in this work. The samples were subjected to other sheet and fiber testing. Tests conducted on select samples included brightness and viscosity. Factors in this experiment included metal addition, chelation, and peroxide charge.

Selective purification of bleached spruce TMP process water by induced air flotation (IAF)

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Dariusz Zasadowski ◽  
Anders Strand ◽  
Anna Sundberg ◽  
Håkan Edlund ◽  
Magnus Norgren
Keyword(s):  
Ph Value ◽  
Additional Treatment ◽  
Process Water ◽  
Ionization Mass ◽  
Paper Mills ◽  
Foaming Agent ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Thermomechanical Pulping ◽  
Air Flotation

Abstract The environmentally benign closure of water systems in paper mills leads to the problem of accumulation of dissolved and colloidal wood substances (DCS) in process water. Notably, pitch affects the pulp and paper production negatively and increases the demand for additional treatment of the process water. In the present article, the purification of thermomechanical pulping process water from the alkaline peroxide bleaching stage has been investigated, with the induced air flotation (IAF) in focus. The following parameters were considered concerning the IAF efficiency to remove detrimental substances: concentration of cationic foaming agent, pH value, calcium concentration, and temperature. The amounts and characteristics of residual DCS were determined by gas chromatography and turbidity measurements. Residual concentrations of the foaming agent dodecyltrimetylammonium chloride were determined by electrospray ionization mass spectrometry. Up to 90% of pitch was removed, whereas hemicelluloses, which are important in preventing pitch problems, remained in the waters. Up to 70% of the pectic acids accounted for the high cationic demand of the process waters were removed by optimization of the IAF parameters. The presented separation process gives new opportunities to a selective purification of the process waters.

Location and fate of carboxyl groups in aspen alkaline peroxide-impregnated chemithermomechanical pulp fibres during alkaline peroxide bleaching

2012 ◽  
Vol 47 (3) ◽  
pp. 557-569
Author(s):  
Yingjuan Fu ◽  
Menghua Qin ◽  
Yanzhu Guo ◽  
Qinghua Xu ◽  
Zongquan Li ◽  
...  
Keyword(s):  
Carboxyl Groups ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Pulp Fibres

Formation of oxalic acid in alkaline peroxide treatment of different wood components

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 393-400 ◽  
Author(s):  
Matti Häärä ◽  
Andrey Pranovich ◽  
Anna Sundberg ◽  
Stefan Willför
Keyword(s):  
Picea Abies ◽  
Oxalic Acid ◽  
Ion Chromatography ◽  
Oxidation Product ◽  
Peroxide Bleaching ◽  
Alkaline Peroxide ◽  
Spruce Bark ◽  
Spruce Wood ◽  
Additional Amount ◽  
Mechanical Pulps

Abstract Oxalic acid (OA), formed as an oxidation product in alkaline peroxide bleaching (P) of mechanical pulps, can form a sparingly soluble salt with calcium and cause severe scale deposit problems. The focus of this work was the question how much OA is formed from the different components of spruce (Picea abies (L.) Karst.), i.e., from cellulose, lignin, hemicelluloses, extractives, and bark, during the P-stage of bleaching. Isolated wood components and monosaccharides typical for spruce hemicelluloses and pectins were treated with chemicals of P-stage for 90 min at 73°C, and the released OA was analyzed by ion chromatography. Most OA was formed from galacturonic and glucuronic acids, xylans, and lignin. Taking into account the content of these substances in spruce wood, lignin can be regarded as the major source of oxalate. Untreated spruce bark was found to contain substantial amounts of oxalate, and an additional amount of oxalate was formed in the P-stage. It is evident that effective debarking is essential, not only for pulp brightness, but also for the control of calcium oxalate formation.

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