scholarly journals Understanding the effect of severity factor of prehydrolysis on dissolving pulp production using prehydrolysis kraft pulping and elemental chlorine-free bleaching sequence

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 4323-4336
Author(s):  
Wei Wei ◽  
Zhongjian Tian ◽  
Xingxiang Ji ◽  
Qiang Wang ◽  
Jiachuan Chen ◽  
...  
Keyword(s):  
Fiber Quality ◽  
Degree Of Polymerization ◽  
Kraft Pulping ◽  
Dissolving Pulp ◽  
Quality Analysis ◽  
X Ray Diffraction ◽  
Severity Factor ◽  
Elemental Chlorine ◽  
Prehydrolysis Kraft ◽  
Temperature Time

Prehydrolysis kraft pulping is an effective approach to produce dissolving pulp, which can be used for viscose application. The prehydrolysis process using hot liquid water could remove hemicellulose and loosen the compact cell wall, thus facilitating subsequent pulping and bleaching processes. In this study, the composite severity factor (CSF) was used to reveal the intensity of prehydrolysis treatment and its effect on the pulping and bleaching process by combining the temperature, time, and pH variables. Results showed that the optimum CSF was 6.61, which produced a pulp with α-cellulose of 92.3%, degree of polymerization (DP) of 1081, brightness of 85.1% ISO, and Kappa number of 0.61. In addition, the fiber quality, crystalline structure, and microstructure of pulps were characterized by FQA (fiber quality analysis), XRD (X-ray diffraction), and SEM (scanning electron microscopy).

scholarly journals PENGGUNAAN XILANASE PADA PEMUTIHAN DISSOLVING PULP Acacia crassicarpa

2015 ◽  
Vol 5 (02) ◽  
Author(s):  
Susi Sugesty ◽  
Teddy Kardiansyah ◽  
Wieke Pratiwi
Keyword(s):  
Chlorine Dioxide ◽  
Dissolving Pulp ◽  
Raw Material ◽  
National Standard ◽  
Cellulose Content ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Free Process ◽  
Acacia Crassicarpa ◽  
Prehydrolysis Kraft

The use of xylanase in pulp bleaching process is intended to reduce chemicals consumption in pulp industry that still using chlorine compounds (chlorine dioxide), so the bleaching stage needs to be modified without reducing the quality of dissolving pulp. Dissolving pulp was produced from six-year-old Acacia crassicarpa as raw material by the Prehydrolysis-Kraft process, then the pulp was bleached with the ECF (elemental chlorine free) process using xylanase (X) and oxygen (O) as comparison at the early stage of bleaching. The sequences of process include X/ODEDED (xylanase or oxygen; chlorine dioxide; extraction-1; chlorine dioxide-1; extraction-2; chlorine dioxide -2). Results showed that the dissolving pulp with active alkali of 22%, sulphidity of 30%, the temperature of 165oC, and the ratio of 1:4 is the optimal condition. Cellulose content, viscosity and brightness were above 94%, 6.2 cP and 88% ISO, respectively.The dissolving pulp produced with the application of xylanase has better quality than the oxygen one, and meets the requirement according to Indonesia National Standard (SNI 0938:2010, pulp rayon).Keywords: Acacia crassicarpa, xylanase, Prehydrolysis-Kraft, dissolving pulp, rayon pulpABSTRAKPenggunaan xilanase pada proses pemutihan pulp dimaksudkan untuk mengurangi konsumsi bahan kimia yang digunakan selama ini di industri pulp, yang masih menggunakan senyawa klorin (klorin dioksida), untuk itu perlu dilakukan modifikasi pada tahap pemutihannya tanpa mengurangi kualitas dissolving pulp yang dihasilkan. Pembuatan dissolving pulp dilakukan menggunakan bahan baku kayu Acacia crassicarpa berumur 6 tahun dengan proses Prahidrolisa–Kraft, selanjutnya pulp diputihkan dengan proses ECF (Elemental Chlorine Free) menggunakan xilanase (X) dan oksigen (O) sebagai pembanding pada awal pemutihan dengan 6 tahapan proses, yaitu X/ODEDED (xilanase atau oksigen; klorin dioksida; ekstraksi-1; klorin dioksida-1; ekstraksi-2; klorin dioksida-2) dengan perlakuan oksigen sebagai pembanding. Hasil pembuatan dissolving pulp dengan alkali aktif 22%, sulfiditas 30%, suhu 165oC, rasio 1:4 adalah kondisi yang optimal. Kandungan selulosa, viskositas dan derajat cerah yang diperoleh masing-masing yaitu di atas 94%, 6,2 cP dan 88% ISO. Kualitas dissolving pulp hasil pemutihan dengan penambahan xilanase lebih tinggi daripada menggunakan oksigen dan memenuhi persyaratan spesifikasi SNI 0938:2010, pulp rayon. Kata kunci : Acacia crassicarpa, xilanase, Prahidrolisa-Kraft, dissolving pulp, pulp rayon

Preparation of acetate-grade dissolving pulp from eucalyptus by processes including alkaline pretreatment and combined post-treatments with xylanase and alkali

TAPPI Journal ◽  
2013 ◽  
Vol 12 (9) ◽  
pp. 19-24
Author(s):  
WEN LIU ◽  
SHUKE ZHOU ◽  
XIAOHUA QI ◽  
JUNWEN PU
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hydroxide ◽  
Degree Of Polymerization ◽  
Kraft Pulping ◽  
Dissolving Pulp ◽  
Alkaline Pretreatment ◽  
Cellulose Content ◽  
Optimal Conditions ◽  
Pulp Bleaching ◽  
Sodium Hydroxide Concentration

In this investigation, alkaline pretreatment before kraft pulping and combined post-treatments with xylanase and alkali after bleaching were applied to obtain an acetate-grade dissolving pulp. Bleaching sequences using oxygen or hydrogen peroxide were also studied. The brightness, α-cellulose content, and degree of polymerization (DP) of the bleached pulps from different bleaching sequences were evaluated. Alkaline pretreatment resulted in a higher α-cellulose content in the pulp. When a D1ED2P bleaching sequence was applied, the pulp obtained had an ISO brightness of 87.5%, a DP of 1050, and an α-cellulose content of 92.7%. The requirements for an acetate-grade dissolving pulp can then be met when followed by combined post-treatments with xylanase and alkali under the optimal conditions of 120 IU•g–1 xylanase dosage and 4% sodium hydroxide concentration.

Study on Technology of Pre-Hydrolysis Pretreament in Bagasse Dissolving Pulp Preparation Process

2014 ◽  
Vol 886 ◽  
pp. 204-211 ◽  
Author(s):  
Ping Zheng ◽  
Wen Qian Li ◽  
Lie Jiang ◽  
Cheng Rong Qin
Keyword(s):  
Raw Materials ◽  
Cellulose Degradation ◽  
Fiber Quality ◽  
Dissolving Pulp ◽  
Raw Material ◽  
Quality Analysis ◽  
Optimum Process ◽  
Process Conditions ◽  
Cellulose Content ◽  
Hydrolysis Process

This research used bagasse as raw material, through xylanase biological treatment process, preparative bagasse dissolving pulp. The optimum process conditions of sulfuric acid pre-hydrolysis were as below: Acid dosage 0.10%, 150°C, 90min. After pre-hydrolysis, cellulose content of the raw materials increased 18.45%, and pentosan decreased 14.49%. The fiber quality analysis showed fiber length and width were reduced, the tiny fiber content was decreased after acid pre-hydrolysis; HPLC analysis showed the optimum acid pre-hydrolysis process which can reduce the inevitable cellulose degradation effectively,hemicelluloses were hydrolyzed furthest at the same time; FTIR spectrum analysis showed acid pre-hydrolysis process can dissolve a lot of hemicelluloses.

Prehydrolysis kraft pulping of jute cutting and caddis mixture for rayon production

TAPPI Journal ◽  
2019 ◽  
Vol 18 (5) ◽  
pp. 287-293 ◽  
Author(s):  
JANNATUN NAYEEM ◽  
M. SARWAR JAHAN ◽  
RAZIA SULTANA POPY ◽  
M. NASHIR UDDIN ◽  
M.A. QUAIYYUM
Keyword(s):  
Kraft Pulping ◽  
Kappa Number ◽  
Pulp Yield ◽  
Solid Residue ◽  
Rayon Production ◽  
Kraft Cooking ◽  
Prehydrolysis Kraft

Jute cutting, jute caddis, and cutting-caddis mixtures were prehydrolyzed by varying time and temperature to get about 90% prehydrolyzed yield. At the conditions of 170°C for 60 min of prehydrolysis, the yield for 100% jute cutting was 76.3%, while the same for jute caddis was only 67.9%. But with prehydrolysis at 150°C for 60 min, the yield was 90% for jute cutting, where 49.94% of original pentosan was dissolved and prehydrolysis of jute caddis at 140°C in 60 min yielded 86.4% solid residue. Jute cutting-caddis mixed prehydrolysis was done at 140°C for 30 min and yielded 92% solid residue for 50:50 cutting-caddis mixtures, where pentosan dissolution was only 29%. Prehydrolyzed jute cutting, jute caddis, and cutting-caddis mixtures were subsequently kraft cooked. Pulp yield was only 40.9% for 100% jute cutting prehydrolyzed at 170°C for 60 min, which was 10.9% lower than the prehydrolysis at 140°C. For jute cutting-caddis mixed prehydrolysis at 140°C for 45 min followed by kraft cooking, pulp yield decreased by 3.3% from the 100% cutting to 50% caddis in the mixture, but 75% caddis in the mixture decreased pulp yield by 6.7%. The kappa number 50:50 cutting-caddis mixture was only 11.3. Pulp bleachability improved with increasing jute cutting proportion in the cutting-caddis mixture pulp.

Study on Influence of Silicate Morphology Based on pH Value

2012 ◽  
Vol 454 ◽  
pp. 324-328
Author(s):  
Yan He ◽  
Ya Jing Liu ◽  
Yong Lin Cao ◽  
Li Xia Zhou
Keyword(s):  
Silicic Acid ◽  
Ph Value ◽  
Colorimetric Method ◽  
Absorption Spectrometry ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
The Stability

Infra-red absorption spectrometry, X-ray diffraction observations and characterization tests based on silicon molybdenum colorimetric method were used to investigate the optimal pH value controlling the stability of the silicic acid form. The experiment process was done by using sodium silicate as raw material. The results showed that the solution of silicate influenced the polymerization. The active silicic acid solution with a certain degree of polymerization was obtained by controlling the pH values.

scholarly journals Nickel-phenanthroline Complex Supported on Mesoporous Carbon as a Catalyst for Carboxylation under CO2 Atmosphere

2021 ◽  
Vol 16 (1) ◽  
pp. 111-119
Author(s):  
Iman Abdullah ◽  
Riri Andriyanti ◽  
Dita Arifa Nurani ◽  
Yuni Krisyuningsih Krisnandi
Keyword(s):  
Mesoporous Carbon ◽  
Nickel Complex ◽  
Solid Support ◽  
Soft Template ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Phenanthroline Complex ◽  
Temperature Time ◽  
Open Access Article

Carbon dioxide is a highly potential renewable C1 source for synthesis of fine chemicals. Utilization of CO2 in carboxylation reactions requires catalysts, such as: nickel complex for CO2 activation. However, the use of homogeneous catalysts in the reaction is still less efficient due to the difficulty of separating the product and catalyst from reaction mixture. Therefore, it is necessary to heterogenize the nickel complex in a solid support such as mesoporous carbon. In this report, mesoporous carbon (MC) prepared from phloroglucinol and formaldehyde through soft template method was used as a solid support for Ni-phenanthroline complex (Ni-phen). The catalyst was characterized by Fourier Transform Infra Red (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscope - Energy Dispersive X-Ray (SEM-EDX), and Surface Area Analyzer (SAA). The result of SAA characterization showed that the pore diameter of MC was 6.7 nm and Ni-phen/MC was 5.1 nm which indicates that the materials have meso-size pores. Ni-phen/MC material was then used as a heterogeneous catalyst in the carboxylation reaction of phenylacetylene under an ambient CO2 pressure. The reactions were carried out in several variations of conditions such as temperature, time and catalyst types. Based on the results of the reaction, the best conditions were obtained at 25 °C for 8 h of reaction time using Ni-phen/MC catalyst.  Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Electrospinning and Post-Spun Chain Conformations of Synthetic, Hydrophobic Poly(α-amino acid)s

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 327 ◽  
Author(s):  
Kesavan Devarayan ◽  
Souta Nakagami ◽  
Shuichi Suzuki ◽  
Ichiro Yuki ◽  
Kousaku Ohkawa
Keyword(s):  
Amino Acid ◽  
Trifluoroacetic Acid ◽  
Average Molecular Weight ◽  
Helical Structure ◽  
Degree Of Polymerization ◽  
Random Coil ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Acid Anhydrides ◽  
Chain Conformations

Electrospinning and post-spun conformations of hydrophobic poly(α-amino acid)s are described in this study. The poly(α-amino acid)s, poly(Gly), poly(l-Ala), poly(l-Val), and poly(l-Leu) were synthesized via corresponding N-carboxy-α-amino acid anhydrides. The average molecular weight and degree of polymerization of these polymers were determined by N-terminus labeling using 2,4-dinitrofluorobenzene and by viscometry in the case of poly(Gly). These poly(α-amino acid)s were electrospun from trifluoroacetic acid or trifluoroacetic acid/dichloromethane solutions. The FT-IR spectroscopy and wide-angle X-ray diffraction indicated that the electrospun poly(l-Ala) and poly(l-Leu) fibers predominantly adopts α-helical structure, whereas poly(l-Val) and poly(Gly) fibers exhibited mainly β-strand and random coil structures, respectively.

scholarly journals Zeolite Adsorption of Chloride from a Synthetic Alkali-Activated Cement Pore Solution

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2019 ◽  
Author(s):  
Jorge Osio-Norgaard ◽  
Wil V. Srubar
Keyword(s):  
Chemical Composition ◽  
Pore Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Chlorine ◽  
Cage Size ◽  
Synthetic Zeolites ◽  
Diffraction Patterns ◽  
Alkali Activated ◽  
Alkali Activated Cement

This work presents experimental evidence that confirms the potential for two specific zeolites, namely chabazite and faujasite (with a cage size ~2–13 Å), to adsorb small amounts of chloride from a synthetic alkali-activated cement (AAC) pore solution. Four synthetic zeolites were first exposed to a chlorinated AAC pore solution, two faujasite zeolites (i.e., FAU, X-13), chabazite (i.e., SSZ-13), and sodium-stabilized mordenite (i.e., Na-Mordenite). The mineralogy and chemical composition were subsequently investigated via X-ray diffraction (XRD) and both energy- and wavelength-dispersive X-ray spectroscopy (WDS), respectively. Upon exposure to a chlorinated AAC pore solution, FAU and SSZ-13 displayed changes to their diffraction patterns (i.e., peak shifting and broadening), characteristic of ion entrapment within zeolitic aluminosilicate frameworks. Elemental mapping with WDS confirmed the presence of small amounts of elemental chlorine. Results indicate that the chloride-bearing capacity of zeolites is likely dependent on both microstructural features (e.g., cage sizes) and chemical composition.

The Effect of Silica Polymerization in Fly Ash on the Strength of Geopolymers

2014 ◽  
Vol 1611 ◽  
pp. 68-74 ◽  
Author(s):  
N. Koshukhova ◽  
I. Zhernovsky ◽  
K. Sobolev
Keyword(s):  
Fly Ash ◽  
Glass Phase ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Integral Parameter ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Wave Numbers ◽  
Different Sources

ABSTRACTThe formation of the structure of geopolymer binders based on low-calcium fly ash is a multifactorial process that depends on the degree of solubility of aluminosilicate components in the solution of alkali activator. It is observed that the geopolymer binders based on fly ash with an identical chemical and mineral composition, the same grain size, and also activated by the same alkalis can result in a different strength.This study is based on the assumption that there is dependence between the solubility of aluminosilicate components and the degree of polymerization of the silicates in glass phase. The degree of SiO2-polymerization is an integral parameter that is equal to the Si molar ratio (fSi) of the silicate component in the glass phase of fly ash. The degree of SiO2-polymerization can be estimated from the molar composition of glass phase, which is determined from the chemical composition and quantitative X-ray diffraction analysis including identification of the amorphous phase composition.The SiO2 polymerization rates of investigated fly ash specimens are confirmed by the IR results, specifically, by comparison of absorption bands of silicate fragments with varying levels of connectivity (Q0-4) in the range of wave numbers of 650–1350 cm-1.The comparative analysis of the correlation of 28-day strength of geopolymer binders based on fly ash from different sources and level of SiO2-polymerization demonstrated an inverse relationship with fSi molar ratio and compressive strength.

Brightness stability of eucalyptus-dissolving pulps: effect of the bleaching sequence

Holzforschung ◽  
2017 ◽  
Vol 71 (7-8) ◽  
pp. 625-631 ◽  
Author(s):  
Jordan Perrin ◽  
Dominique Lachenal ◽  
Christine Chirat
Keyword(s):  
Heat Exposure ◽  
Dissolving Pulp ◽  
Paramagnetic Resonance ◽  
Bleached Pulp ◽  
Alkaline Peroxide ◽  
Elemental Chlorine ◽  
Brightness Reversion ◽  
Dissolving Pulps ◽  
Ultraviolet Resonance Raman

Abstract The factors governing the brightness reversion (BR) of dissolving pulps under heat exposure are investigated. Carbonyl (CO) groups were artificially introduced on fully bleached pulp by sodium hypochlorite (NaClO) oxidation. It was demonstrated that the CO groups are responsible for loss of brightness stability (BS). These groups were partly eliminated by an alkaline extraction stage (E), which improved BS. However, an alkaline peroxide stage (P) was more efficient than E to improve BS, but without any additional CO loss. Moreover, an unbleached dissolving pulp was bleached in the laboratory by elemental chlorine free (ECF) and totally chlorine free (TCF) [ozone-based] sequences to the same brightness. The very low CO content was about the same in both cases. The ECF-bleached pulp showed substantially lower BS than the TCF pulp. These results are interpreted such that the chemistry of chromophores in the unbleached pulp also governs BS. In situ detection of phenolic and quinone chromophores in bleached dissolving pulp was performed by electron paramagnetic resonance (EPR) spectroscopy and ultraviolet resonance Raman (UVRR) spectroscopy. The content of these groups was bleaching-sequence-dependent, which may be related to the BS differences.

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