187 results on '"Alkaline peroxide"'
Search Results
2. Process performance evaluation of different chemical pretreatments of lignocellulosic biomass for bioethanol production.
- Author
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Raina, Neelu, Boonmee, Rattanan, Kirdponpattara, Suchata, Narasingha, Monpilai, Sriariyanun, Malinee, Phitsuwan, Paripok, and Chuetor, Santi
- Subjects
- *
ETHANOL as fuel , *BIOMASS production , *LIGNOCELLULOSE , *ENERGY consumption , *INDUSTRIAL chemistry , *BAGASSE - Abstract
So far, a large number of pretreatment methods have garnered significant attention aimed only at optimizing the reducing sugar and bioethanol yields. This study however, carried out pretreatment of sugarcane bagasse (SCB) using hydrothermal, organosolv, alkaline and alkaline peroxide pretreatment methods comparing their process performance. An evaluation of the energy consumption parameter during pretreatment showed lowest energy use (0.619 kWh/kg) during 5% alkaline peroxide pretreatment. The energy efficiency (0.162 kg bioethanol/kWh) was thus highest whereas the waste generation was lowest (38.895 kg waste/kg bioethanol) during alkaline peroxide pretreatment process. The solid biomass was utilized for enzymatic saccharification and bioethanol fermentation using SSF. Maximum enzyme efficiency and bioethanol yields achieved were 85.02% and 0.101 kg bioethanol/kg biomass respectively. Process performance evaluation can be projected to open up a new avenue for practical implementations of life cycle analysis (LCA) and techno-economic assessment aiding the circular bio-economy approach. [Display omitted] • Chemical pretreatment technologies investigated for process performance evaluation. • Energy efficiency and waste generation used to evaluate process performance. • 0.162 kg bioethanol/kWh- energy efficiency during alkaline peroxide pretreatment. • Also, lowest waste generation (38.895 kg waste/kg bioethanol) was recorded. • NaOH and H 2 O 2 at 5% (w/w) chemical concentration was most effective pretreatment. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Preparation of high-yield carbon quantum dots and paper-based sensors from biomass wastes by mechano-chemical method.
- Author
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Hao, Hong-Chao, Chen, Shuo, Tan, Zi-Xiang, and Jiang, Hong
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QUANTUM dots ,QUANTUM dot synthesis ,HYDROGEN peroxide ,BIOMASS ,SEWAGE disposal plants ,CYANOBACTERIA - Abstract
The synthesis of carbon quantum dots (CQDs) from biomass through a "bottom-up" method has attracted a great deal of interest because of its outstanding environmental and economic advantages. However, the yield of biomass-based CQDs is still low due to the high polymerization of biochar. In this study, we propose a new approach for harvesting high-yield biomass-based CQDs by integrating mechanochemistry and strong chemical oxidation. Ball milling can reduce the particle size and resistance of biochar and increase the contents of C C, while the powerful oxidant HOO
- produced by alkaline hydrogen peroxide can break C C to generate biomass-based CQDs. Using this two-step process, the yields of biomass-based CQDs reached 57.75% for blue-green algae, 65.8% for straw, 47.9% for corn protein meal, and 45.35% for Typha angustifolia. Based on the excellent sensitivity and selectivity for Fe3+ of biomass-based CQDs, CQDs paper-based sensors were prepared for expedient and precise detection of Fe3+ in surface water, wastewater treatment plant effluent, and tap water. When the Fe3+ content is between 0 and 60 μM, the R2 of Fe3+ detection by blue-green algae CQDs can reach 0.9956. This work provides a new and reliable method for the large-scale preparation of biomass-based CQDs and expands their environmental applications. [Display omitted] • A method was proposed to improve the yield of biomass-based carbon quantum dot (CQD). • Ball milling can reduce the resistance of biochar and increase the contents of C C. • This scalable method is applicable to other biomass wastes. • The CQDs has excellent sensitivity and selectivity for Fe3+. • The paper-based CQD sensors are applicable in different water bodies. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
4. Effect of Alkaline peroxide denture cleansers on surface roughness and hardness of Conventional heat cured and CAD/CAM denture base resins
- Author
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Mahmoud Darwish Aly
- Subjects
Materials science ,Distilled water ,Independent samples ,Surface roughness ,Denture base ,Alkaline peroxide ,Composite material ,Denture Cleansers ,Hardness ,After treatment - Abstract
Objectives: This study aimed to evaluate the changes of surface roughness and hardness of conventional heat-cured (CHC) and CAD/CAM PMMA after immersion in alkaline peroxide chemical denture cleansers (DC), simulating one -year of use. Materials and Methods: 30 specimens of CHC, and another 30 specimens of CAD/CAM PMMA were divided into three groups (n= 10), each were immersed in two commercially available alkaline peroxide DC (Corega tablets and Polident tablets) as well as distilled water (control group). The mean surface roughness (Ra) of the specimens was recorded using contact stylus surface analyzer device. The surface hardness (VHN) was recorded using Vickers micro-hardness tester. T‑test for paired observation and independent samples T-test were used to indicate and compare any changes in Ra and hardness between the baseline and after simulated daily immersion in DC for one-year. Results: The tested DC had no significant effect on the Ra and hardness of CAD/CAM PMMA specimens. But both types of DC produced significant increase in Ra and significant decrease in VHN of the CHC PMMA specimens (P < 0.05). The Ra of the CAD/CAM PMMA specimens was significantly lower and the VHN was significantly higher than that of the CHC PMMA after treatment with DC. Conclusions: Alkaline peroxide DC appears not to affect the Ra and hardness of CAD/CAM PMMA. Alkaline peroxide DC produced negative effect on the Ra and hardness of CHC PMMA. CAD/CAM denture base resins might be considered the material of choice to produce more durable dentures.
- Published
- 2021
5. Recycled Polypropylene/Peanut Shell Powder Composites: Pre-Treatment of Lignin Using Alkaline Peroxide
- Author
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Nor Fasihah Zaaba, Hanafi Ismail, and Mariatti Jaafar
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Lignocellulosic ,Peanut shell powder ,Alkaline peroxide ,Lignin removal ,Recycled polypropylene ,Biotechnology ,TP248.13-248.65 - Abstract
This study investigated the performance of recycled polypropylene (RPP)/peanut shell powder (PSP) composites with untreated PSP and treated PSP with alkaline peroxide. The RPP/PSP and RPP/PSP-H2O2 composites were prepared by melt mixing and compression molding at different PSP loadings (10 wt.% to 40 wt.%). The samples were characterized by processing properties, tensile properties, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and water absorption behavior. The treated PSP enhanced the stabilization torque, tensile strength, elongation at break, tensile modulus, and water absorption of RPP/PSP-H2O2 composites. FTIR spectra and SEM showed that the elimination of lignin content strongly influenced the fractured surface and chemical characteristics of the RPP/PSP-H2O2 composites.
- Published
- 2016
- Full Text
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6. Bleaching and Oxidation of Human Hair
- Author
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Robbins, Clarence R. and Robbins, Clarence R.
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- 2012
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7. Alkaline Peroxide Delignification of Corn Stover
- Author
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Beckham, Gregg [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States] (ORCID:000000023480212X)
- Published
- 2017
- Full Text
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8. Conversion Furfural Residues Into Reducing Sugars with the Pretreatment of Ionic Liquid and Alkaline Peroxide.
- Author
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Lin, Keying, Feng, Li, Niu, Kun, Liu, Wanyi, Zhan, Haijuan, and Ma, Baojun
- Abstract
Conversion and reuse of furfural residues are of great significance as the furfural residues are pollution-carrying biomass waste resources. However, the furfural residues must be pretreated to remove the lignin so as to improve the conversion efficiency. Here, we firstly reported an efficient pretreatment method which integrated uses ionic liquid and alkaline peroxide and found the synergic effect of them on the pretreatment of furfural residues. The pretreatment using [Bmim]Cl and NaOH/H
2 O2 shows the highest lignin elimination efficiency of 75.09%, which is 1.95 times of that [Bmim]Cl and 1.55 times of that NaOH/H2 O2 , respectively. The highest yield of reducing sugars is 50.4%. The pretreatment synergistic effect is attributed to the swelling property of the ionic liquid and the delignification of the alkaline peroxide. The effect of ionic liquids structures on pretreatments was also researched and the ionic liquids with Cl and short branched chain are superior for the lignin removal. This article gives an alternative technique for the pretreatment and conversion of furfural residues. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
9. Effect of alkaline pretreatments on the enzymatic hydrolysis of wheat straw.
- Author
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Kontogianni, Nikoleta, Barampouti, Elli Maria, Mai, Sofia, Malamis, Dimitris, and Loizidou, Maria
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WHEAT straw ,LIGNOCELLULOSE ,HYDROGEN peroxide ,DELIGNIFICATION ,HYDROLYSIS ,RAW materials ,LIGNINS - Abstract
Lignocellulosic materials are mainly consisted of lignin, cellulose, and hemicellulose. Lignin is recognized as the main obstacle for the enzymatic saccharification of cellulose towards the fermentable sugars' production. Hence, the removal of lignin from the lignocellulosic feedstock is beneficial for reducing the recalcitrance of lignocellulose for enzymatic attack. For this purpose, various different alkaline pretreatments were examined in order to study their effect on the enzymatic saccharification of wheat straw, as a typical lignocellulosic material. Results revealed that the alkaline pretreatments promoted delignification reactions. Regarding the removal of lignin, the most efficient pretreatments were alkaline treatment with hydrogen peroxide 10% and NaOH 2% autoclave with delignification efficiencies of 89.60% and 84.86% respectively. X-ray diffraction analysis was performed to enlighten the structural changes of raw and pretreated materials. The higher the delignification of the raw material, the higher the conversion of cellulose during enzymatic saccharification. In all cases after enzymatic saccharification, the cellulosic conversion was much higher (32–77%) than the untreated wheat straw (8.6%). After undergoing alkaline peroxide 10% pretreatment and cellulase treatment, 99% of the initial raw straw was eventually solubilized. Thus, wheat straw could be considered as an ideal material for the production of glucose with proper pretreatments and effective enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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10. Chemical preconversion of softwood with alkaline hydrogen peroxide: Creating a denser carbohydrate feedstock supply for biorefinery systems.
- Author
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Yi, Xin, Huang, Lang, Jiang, Jinxue, and Wang, Qingwen
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HYDROGEN peroxide ,CARBOHYDRATES ,SOFTWOOD ,NATURAL resources ,HEMICELLULOSE ,LEAD abatement - Abstract
Moderate chemical pretreatment to increase the energy density and improve of chemical components, also called preconversion, is an emerging strategy to secure feedstock supplies in biorefinery systems. This study investigates the alkaline hydrogen peroxide (AHP) preconversion of softwood for its potential use at distributed depots, which are preprocessing facilities near natural resource sources. Specifically, this study quantified the effects of treatment conditions such as hydrogen peroxide concentration, reaction temperature, and time on chemical compositions and enzymatic hydrolysis. Results show that AHP preconversion led to the removal of lignin and hemicellulose from the recovered solids. Increasing the concentration of hydrogen peroxide decreased carbohydrate recovery after the preconversion process. There was no significant difference of total sugar yield from enzymatic hydrolysis at various hydrogen peroxide loadings. Carbohydrate recovery was over 96% after preconversion at 30 °C compared to that of the untreated sample. A longer reaction time increased the total enzymatic sugar yields. Morphological analysis revealed significant structure modification, with cracks and fragments in Douglas-fir after AHP preconversion. • AHP mild chemical preconversion improves the carbohydrates density of feedstock. • AHP prevonversion results in removal of partial hemicellulose and lignin. • The effect of AHP process conditions on carbohydrate recovery was elucidated. • Carbohydrate recovery of over 96% was obtained at lower temperature condition. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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11. Combination of Low-pressure Steam Explosion and Alkaline Peroxide Pretreatment for Separation of Hemicellulose
- Author
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Yang Xing, Zhaoqin Su, Kun Wang, Lihong Deng, and Jianxin Jiang
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Lespedeza stalk ,Hemicelluloses ,Combined pretreatment ,Steam explosion ,Alkaline peroxide ,Biotechnology ,TP248.13-248.65 - Abstract
Low-pressure steam explosion (LPSE) combined with alkaline peroxide (AP) pretreatment was first employed to separate hemicellulose from Lespedeza stalks. The monosaccharide composition and molecular weight distribution of the obtained hemicellulose fractions were characterized in this study. The results show that the hemicellulose extracted from Lespedeza stalks consisted of xylose, glucose, galactose, and mannose, which was a mixture of arabinoxylans and xyloglucans or β-glucans. The yield of hemicellulose fractions after AP pretreatment ranged from 11.2% (2.5% hydrogen peroxide (H2O2), w/v for 12 h) to 12.2% (3.3% H2O2, w/v for 72 h). The molecular weight of hemicellulose decreased from 2,458 g/mol to 1,984 g/mol after AP pretreatment, indicating its degradation reaction. The structure of hemicellulose was analyzed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and heteronuclear single quantum coherence. The AP pretreatment partially cleaved the backbone and the ether linkage between lignin and hemicelluloses. Also, branched-chain α-D-arabinofuranosyl in which β-D-xylose substituted at the C-3 position (monosubstituted) was removed, illustrating a partial debranching reaction. Therefore, the combination of low-pressure steam explosion and alkaline peroxide pretreatment (LPSE-AP) is an effective pretreatment method to separate hemicellulose from Lespedeza stalk.
- Published
- 2014
- Full Text
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12. Effects of Hot Water Pre-Extraction on Energy Consumption and Brightness of Bamboo Alkaline Peroxide Mechanical Pulp
- Author
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Xiheng Kang, Shuangfei Wang, Yan Jiang, Min Wu, Xueping Song, and He Hui
- Subjects
Biomaterials ,Bamboo ,Brightness ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Pulp (paper) ,engineering ,Bioengineering ,Alkaline peroxide ,Energy consumption ,engineering.material ,Pre extraction ,Pulp and paper industry - Abstract
The main purpose of this paper was to investigate the effects of hot water pre-extraction (HWP) on the refining energy consumption and the brightness of bamboo alkaline peroxide mechanical pulp (APMP). It was found that compared with un-extraction, the refining energy consumption dropped by about one-third after HWP. The reduction of energy consumption was proved through enhancing the channel of water and chemicals into inferior fiber based on the surface characterization of bamboo. Scanning electron microscope (SEM) images showed that the HWP made the fibers' structure loose and porous. Both pore volume and specific surface area were increased significantly after HWP, by 260.00% and 1804.76%, respectively. A decrease in pulp brightness was mainly due to the formation of new chromophore groups during the HWP process. The results of 13C nuclear magnetic resonance spectroscopy (13C-NMR) illustrated that some structures of milled wood lignin (MWL), such as guaiacyl, etherificated guaiacyl, and aromatic units, were increased during the HWP process. However, some lignin-links units of α-O-4, β-O-4, and some carbohydrate structures such as xylan, α- and β-glucose, and β-and β-mannose in lignin-carbohydrate complex (LCC) were evidently degraded. Additionally, most of the lignin and LCC were degraded under the simulative conditions of HWP bamboo. Furthermore, the analysis of UV spectrophotometry indicated that HWP was conductive to the generation of chromophore groups such as conjugated carbonyl, catechol, and o-benzoquinone.
- Published
- 2020
13. Evaluación de técnicas de pretratamiento en buchón de agua (Eichhornia crassipes) para la producción de bioetanol
- Author
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Karen S Ospino, Elkin Gomez, and Luis A. Rios
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Eichhornia crassipes ,biology ,Chemistry ,Strategy and Management ,Alkaline peroxide ,Geotechnical Engineering and Engineering Geology ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Horticulture ,General Energy ,Solid fraction ,Biofuel ,Ethanol yield ,Ethanol fuel ,Food Science - Abstract
espanolSe evaluaron cuatro pretratamientos del Buchon de Agua (Eichhornia crassipes) para su transformacion en azucares y etanol. El Buchon de Agua es una planta acuatica de rapido crecimiento que representa un serio problema de invasiones por lo que se propone su transformacion en etanol, teniendo en cuenta la inminente escasez de combustibles fosiles a nivel mundial. En esta seleccion preliminar el Buchon de Agua exhibio caracteristicas constitutivas de tipo quimico, que lo convierten en una materia prima promisoria para produccion de etanol, obteniendose, rendimientos de 17,15 g/l, 18,10 g/l, 17,73 g/l y 4,53 g/l con los pretratamientos remojo con amoniaco, delignificacion alcalina, pretratamiento con acido diluido y peroxido alcalino, respectivamente. Finalmente, se seleccionaron los pretratamientos con acido diluido y delignificacion alcalina para ser utilizados con mayor profundidad mediante la aplicacion de un diseno experimental, obteniendose un rendimiento de etanol de 190,35 l/ton biomasa seca alimentada para el pretratamiento acido diluido y 197,33 l/ton biomasa seca alimentada para el pretratamiento delignificacion alcalina, a partir de la fraccion solida. EnglishWater Hyacynth (Eichhornia crassipes) is a fast growing aquatic plant that represents a serious problem of invasion, so its transformation into ethanol is proposed as a solution, taking into account the imminent scarcity of fossil fuels worldwide and the panorama of opportunity that is lived in the world due to the legislation on biofuels. For this, four different pretreatments were evaluated taking into account production of sugars and final ethanol yield to select the most promising. In this preliminary selection, the Water Hyacinth exhibited chemical type compositional characteristics that make it a promising raw material for ethanol production, obtaining yields of 17.15 g/l, 18.10 g/l, 17.73 g/l and 4,53 g/l with the pretreatments aqueous ammonia soaking, alkaline delignification, pretreatment with diluted acid and alkaline peroxide, respectively. Finally, the pretreatments with diluted acid and alkaline delignification were selected to be studied more deeply through the application of an experimental design, obtaining an ethanol yield (better design conditions). 190.35 l/ton dry biomass fed to the diluted acid pretreatment and 197.33 l/ton dry biomass fed to the alkaline delignification pretreatment, from the solid fraction.
- Published
- 2020
14. Influence of alkaline peroxide assisted and hydrothermal pretreatment on biodegradability and bio-hydrogen formation from citrus peel waste
- Author
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Franciele Pereira Camargo, Maria Bernadete Amâncio Varesche, Isabel Kimiko Sakamoto, and Iolanda Cristina Silveira Duarte
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biology ,Renewable Energy, Sustainability and the Environment ,Chemistry ,Hydrogen formation ,Energy Engineering and Power Technology ,Alkaline peroxide ,02 engineering and technology ,Biodegradation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,biology.organism_classification ,01 natural sciences ,Hydrothermal circulation ,0104 chemical sciences ,HIDROGÊNIO ,Acetic acid ,chemistry.chemical_compound ,Fuel Technology ,Clostridium ,Fermentation ,0210 nano-technology ,Bacteria ,Nuclear chemistry - Abstract
The effect of pretreatments by hydrothermolysis (180 °C; 15 min) and alkaline delignification (NaOH 5M; H2O2 1%; 24 h) in citrus peel waste (CPW) was evaluated, as well as the effect on H2, organic acids and alcohols production, in addition to characterization of the microbial community involved in fermentation. Batch reactors at 37 °C were operated with 3 gTVS/L of CPW with allochthonous consortium (UASB reactor sludge; 2 gTVS/L) and autochthonous of CPW (1.5 gTVS/L) as inocula. H2 production was higher in reactors with in natura CPW (13.31 mmol/L) compared to hydrothermolysis (8.19 mmol/L) and alkaline delignification (7.27 mmol/L). The acetogenic pathway was predominant in the in natura CPW (4,355 mg/L acetic acid). The most abundant genera in the in natura CPW and after hydrothermolysis were Clostridium (18.97 and 12.90%, respectively) and Ruminiclostridium (16.65 and 1.04%, respectively) commonly related to cellulolytic bacteria and/or H2 production.
- Published
- 2019
15. Properties Enhancement of Mengkuang Leaf Fiber/Ethylene‐Vinyl Acetate/Natural Rubber Thermoplastic Elastomer Composites by Alkaline Peroxide Bleaching Treatment
- Author
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Arjulizan Rusli, Faiezah Hashim, and Hanafi Ismail
- Subjects
Marketing ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Ethylene-vinyl acetate ,Alkaline peroxide ,General Chemistry ,chemistry.chemical_compound ,chemistry ,Natural rubber ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Fiber ,Thermoplastic elastomer ,Composite material - Published
- 2019
16. A COMPARISON BETWEEN THE EFFECTS OF OZONE AND ALKALINE PEROXIDE TREATMENTS ON TMP PROPERTIES AND SUBSEQUENT LOW CONSISTENCY REFINING
- Author
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James A. Olson, Xue Feng Chang, and Rodger P. Beatson
- Subjects
Ozone ,Alkaline peroxide ,Low consistency refining ,Energy ,TMP ,Biotechnology ,TP248.13-248.65 - Abstract
As part of a program to reduce electrical energy consumption in the refining process, the effects of the ozone and alkaline peroxide treatments on fibre and handsheet properties, prior and subsequent to low consistency (LC) refining, were assessed and compared by applying different levels of ozone and a range of peroxide and alkali charges to a primary stage hemlock thermomechanical pulp (TMP). Both highly alkaline peroxide treatments and ozone treatments decreased the specific energy required for strong mechanical pulp. The improvement in pulp strength through alkaline peroxide treatment mainly resulted from pulp surface changes caused by generation of acid groups. The highly alkaline peroxide treatments significantly increased pulp brightness but did not promote the further fibrillation during the subsequent LC refining. On the other hand, ozone treatments provided tensile strength increases, along with small brightness enhancements for the dark hemlock TMP, and increased the tensile gains obtained through LC refining. The effects of ozone treatments on tensile strength before and after LC refining were the result of pulp surface modifications, fibre swelling, and loss of fibre wall integrity due to non-selective chemical attack. High levels of ozone treatment caused tear strength to decrease during subsequent LC refining.
- Published
- 2011
17. Formic acid pulping of crops residues available in Bangladesh
- Author
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M. Sarwar Jahan, M. A. Quaiyyum, Taslima Ferdous, and M. Nashir Uddin
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Renewable Energy, Sustainability and the Environment ,Chemistry ,Formic acid ,020209 energy ,Pulp (paper) ,Papermaking ,Pulpwood ,food and beverages ,Alkaline peroxide ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,Raw material ,Pulp and paper industry ,Kappa number ,01 natural sciences ,Peroxyformic acid ,stomatognathic diseases ,chemistry.chemical_compound ,stomatognathic system ,0202 electrical engineering, electronic engineering, information engineering ,engineering ,0105 earth and related environmental sciences - Abstract
Bangladesh is a densely populated agricultural country. As the allocated forestland for pulpwood production is very limited and a substantial amount of crops residues are generated each year, the latter can substitute pulpwood. But it is hard to use crops residues as pulping raw materials in a conventional pulping process due to its high content of silica and fines. It was observed that formic acid (FA) pulping process can overcome these limitations. In this context, fourteen residues of crops produced in Bangladesh were evaluated by FA pulping with varying FA charge for 4 h at the boiling temperature followed by peroxyformic acid (PFA) treatment under constant conditions. It was observed that pulp yield and delignification degree decreased with FA charge. Also, PFA treatment further reduced the kappa number of pulps. Final pulp yields were 39–51% with the kappa number of 12–28 depending on crops residues. Holocellulose and α-cellulose content in crops residues were positively correlated (R2 = 0.95) with pulp yield at 0% level of significance. Pulps were bleached by alkaline peroxide bleaching and brightness reached to about 80% with acceptable papermaking properties.
- Published
- 2019
18. Preparation and Characterization of Lignin-Containing Cellulose Nanofibril from Poplar High-Yield Pulp via TEMPO-Mediated Oxidation and Homogenization
- Author
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Yonghao Ni, Chunping Wang, An Wang, Yangbing Wen, Shuo Yang, Zhaoyang Yuan, Jianfeng Xu, Bing Wei, Xiongli Liu, and Jialei Qu
- Subjects
Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Pulp (paper) ,fungi ,food and beverages ,Alkaline peroxide ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Homogenization (chemistry) ,0104 chemical sciences ,stomatognathic diseases ,chemistry.chemical_compound ,stomatognathic system ,chemistry ,Chemical engineering ,engineering ,Environmental Chemistry ,Lignin ,Thermal stability ,Cellulose ,0210 nano-technology - Abstract
In this study, a poplar high-yield pulp [preconditioning refiner alkaline peroxide mechanical pulp (P-RC APMP)] was used to produce lignin-containing cellulose nanofibril (LCCNF) dispersions throug...
- Published
- 2019
19. Improved enzymatic hydrolysis and ethanol production by combined alkaline peroxide and ionic liquid‐water mixtures pretreatment of rice straw
- Author
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Xiao-Chun Luo, Shuang Li, Min Zhuo, Yu-Tao Wang, Ting Zhou, Ming‐Jun Zhu, Ying-Ying Hong, and Si-Ming Zhu
- Subjects
Chromatography ,Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Organic Chemistry ,Alkaline peroxide ,Rice straw ,Pollution ,Inorganic Chemistry ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Enzymatic hydrolysis ,Ionic liquid ,Ethanol fuel ,Fermentation ,Waste Management and Disposal ,Biotechnology - Published
- 2019
20. Conversion Furfural Residues Into Reducing Sugars with the Pretreatment of Ionic Liquid and Alkaline Peroxide
- Author
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Li Feng, Wanyi Liu, Haijuan Zhan, Kun Niu, Baojun Ma, and Keying Lin
- Subjects
0106 biological sciences ,Environmental Engineering ,integumentary system ,Renewable Energy, Sustainability and the Environment ,Chemistry ,020209 energy ,Energy conversion efficiency ,Biomass ,Alkaline peroxide ,02 engineering and technology ,Furfural ,01 natural sciences ,chemistry.chemical_compound ,010608 biotechnology ,Yield (chemistry) ,Ionic liquid ,0202 electrical engineering, electronic engineering, information engineering ,medicine ,Lignin ,Swelling ,medicine.symptom ,Waste Management and Disposal ,Nuclear chemistry - Abstract
Conversion and reuse of furfural residues are of great significance as the furfural residues are pollution-carrying biomass waste resources. However, the furfural residues must be pretreated to remove the lignin so as to improve the conversion efficiency. Here, we firstly reported an efficient pretreatment method which integrated uses ionic liquid and alkaline peroxide and found the synergic effect of them on the pretreatment of furfural residues. The pretreatment using [Bmim]Cl and NaOH/H2O2 shows the highest lignin elimination efficiency of 75.09%, which is 1.95 times of that [Bmim]Cl and 1.55 times of that NaOH/H2O2, respectively. The highest yield of reducing sugars is 50.4%. The pretreatment synergistic effect is attributed to the swelling property of the ionic liquid and the delignification of the alkaline peroxide. The effect of ionic liquids structures on pretreatments was also researched and the ionic liquids with Cl and short branched chain are superior for the lignin removal. This article gives an alternative technique for the pretreatment and conversion of furfural residues.
- Published
- 2018
21. Impact of double alkaline peroxide pretreatment on enzymatic hydrolysis of palm fibre
- Author
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Wangliang Li, Yuming Zhang, and Shengqiang Chang
- Subjects
0106 biological sciences ,020209 energy ,Materials Science (miscellaneous) ,Biomass ,Alkaline peroxide ,02 engineering and technology ,Cellulase ,lcsh:Chemical technology ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Hydrolysis ,010608 biotechnology ,Enzymatic hydrolysis ,0202 electrical engineering, electronic engineering, information engineering ,Lignin ,lcsh:TP1-1185 ,chemistry.chemical_classification ,biology ,Process Chemistry and Technology ,Reducing sugar ,Fuel Technology ,chemistry ,Yield (chemistry) ,biology.protein ,Nuclear chemistry - Abstract
A double pretreatment was developed to improve the efficiency of enzymatic hydrolysis and to increase the sugars production from palm fibre in batch and fed-batch systems. After alkaline peroxide pretreatment using NaOH-H2O2 solution, rigid structure of palm fibre was broken and partial of the hemicelluloses and lignin were removed. Compared with cellulase Accellerase® 1500, when using the conjunction of Accellerase® 1500 and Optimash BG, the conversion ratio increased from 35.9% to 45.0% and the reducing sugar yield increased from 245 mg/g substrate to 307 mg/g substrate. To further increase the hydrolysis efficiency, double pretreatment with NaOH-H2O2 solution was used to treat the hydrolysized residues. Then, the hydrolysis ratio reached 93% and reducing sugar yield was 752 mg/g substrate. Fed-batch enzymatic hydrolysis was carried out with 7% (w/v) solids loading and 0.3 mL/g substrate. Then, 7% solids were fed consecutively at 12 h, 24 h, 36 h and 48 h. After 144 h, the final concentration of reducing sugar reached 214.0 g/L and total biomass conversion ratio was 75.23%. Keywords: Cellulase, Palm fibre, Reducing sugar, Lignin, Alkaline peroxide pretreatment
- Published
- 2018
22. Antimicrobial Activity of Different Solutions on Denture Base Materials
- Author
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Bilgen Ozdemir, Ayşe Rüveyda Uğur, Ali Riza Tuncdemir, and Kübra T. Kahraman
- Subjects
business.industry ,Abrasive ,Dentistry ,Alkaline peroxide ,Antimicrobial ,chemistry.chemical_compound ,Infectious Diseases ,chemistry ,Distilled water ,Surface preparation ,Oral microbiology ,Sodium hypochlorite ,Pediatrics, Perinatology and Child Health ,Denture base ,Medicine ,business - Abstract
There are a few chemical solutions used for prosthetic cleaning and they have different antimicrobial effects on denture materials. The aim of this study is to evaluate the efficacy of various chemical solutions used in prosthetic cleaning. For this purpose, 40 specimens of polymethylmethacrylate (PMMA-Meliodent, HeraeusKulzer, Hanau, Germany), which is the most commonly used material in conventional prostheses, and 40 specimens of Deflex (Nuxen SRL, Ayacucho 1053 3-A, Cap. Fed. Buenos Aires, Argentina), which is polyamide-containing semi-flexible acrylic, were molded using a template at the laboratory of Dentistry Faculty. Leveling began with abrasive burs and Stones followed by the sanding with medium and thin discs. Surface preparation was done using wet pumice and felt followed by polishing with gypsum-alcohol and rotary soft brush. The evaluated three solutions are Corega cleaning tablets containing alkaline peroxide, 0.2% chlorhexidine gluconate (CG) and 1% sodium hypochlorite (NaOCl). Distilled water was used as the control group. When both groups of polymers were evaluated in respect to the Candida growth after they were kept in liquid containing NaOCl, Corega, and CG, it was observed that only the acrylics that were kept in Corega revealed Candida growth. It was concluded that Corega could not sufficiently inhibit the growth of Candida albicans which is the one of the most common microorganisms in the oral flora of pediatric and elderly patients. NaOCl and CG can be used safely and effectively for denture cleaning.
- Published
- 2018
23. Carboxymethylation of polysaccharide isolated from Alkaline Peroxide Mechanical Pulping (APMP) waste liquor and its bioactivity
- Author
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Ting Chen, Haitang Liu, Fufeng Liu, Rui Liu, Mingqiang Zhu, Beibei Chen, Chuanling Si, Jie Li, Meiyun Zhang, Jing Liu, and Yongzhen An
- Subjects
Proton Magnetic Resonance Spectroscopy ,Substituent ,Alkaline peroxide ,02 engineering and technology ,Microbial Sensitivity Tests ,Raw material ,Alkalies ,Polysaccharide ,Biochemistry ,Methylation ,PC12 Cells ,Antioxidants ,03 medical and health sciences ,chemistry.chemical_compound ,Structural Biology ,Polysaccharides ,Salmonella ,Spectroscopy, Fourier Transform Infrared ,Animals ,Carbon-13 Magnetic Resonance Spectroscopy ,Molecular Biology ,030304 developmental biology ,chemistry.chemical_classification ,Waste Products ,0303 health sciences ,Moisture absorption ,Temperature ,food and beverages ,Biological activity ,Humidity ,General Medicine ,021001 nanoscience & nanotechnology ,Alkali metal ,Xylan ,Anti-Bacterial Agents ,Peroxides ,Rats ,carbohydrates (lipids) ,Molecular Weight ,chemistry ,Xylans ,0210 nano-technology ,Oxidation-Reduction ,Nuclear chemistry ,Bacillus subtilis - Abstract
In recent years, the biological activity of polysaccharides and their derivatives has been widely studied. However, in addition to the natural polysaccharides directly extracted from plants and animals, there are rich polysaccharides in the pulping waste liquor that have not been fully utilized. The extracted polysaccharide from eucalyptus Alkaline Peroxide Mechanical Pulping (APMP) waste liquor was used as a raw material. For the production of carboxymethyl polysaccharide, the effects of temperature (T), the amount of alkali (NaOH) and the amount of etherifying agent (ClCH2COOH) on the degree of substitution (DS) were investigated, the optimal preparation conditions are: reaction time 2 h, temperature 75 °C, and the molar ratio of polysaccharide, NaOH and ClCH2COOH is 1:1:2, the highest DS is 1.47; FT-IR, NMR and GPC were used to characterize the structure and Molecular weight, the results show that the polysaccharide of APMP waste liquor is rich in xylan, and it was proved that the carboxymethyl substitution was successful and the positions of the substituent group were determined. The characterization and biological activity research of xylan polysaccharide (XP) and carboxymethyl xylan polysaccharide (CMXP), such as antioxidation, moisture absorption/retention, bacteriostatic action and cytotoxicity were discussed. CMXP shows better effects compared with XP.
- Published
- 2020
24. Recycled Polypropylene/Peanut Shell Powder Composites: Pre-Treatment of Lignin Using Alkaline Peroxide.
- Author
-
Zaaba, Nor Fasihah, Ismail, Hanafi, and Jaafar, Mariatti
- Subjects
- *
POLYPROPYLENE , *PEANUT hulls , *COMPOSITE materials , *COMPRESSION molding , *FOURIER transform infrared spectroscopy , *SCANNING electron microscopy , *ABSORPTION , *LIGNOCELLULOSE - Abstract
This study investigated the performance of recycled polypropylene (RPP)/peanut shell powder (PSP) composites with untreated PSP and treated PSP with alkaline peroxide. The RPP/PSP and RPP/PSPH2O2 composites were prepared by melt mixing and compression molding at different PSP loadings (10 wt.% to 40 wt.%). The samples were characterized by processing properties, tensile properties, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and water absorption behavior. The treated PSP enhanced the stabilization torque, tensile strength, elongation at break, tensile modulus, and water absorption of RPP/PSP-H2O2 composites. FTIR spectra and SEM showed that the elimination of lignin content strongly influenced the fractured surface and chemical characteristics of the RPP/PSP-H2O2 composites. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
25. Adherend Surface Preparation for Structural Adhesive Bonding
- Author
-
Clearfield, H. M., McNamara, D. K., Davis, Guy D., and Lee, Lieng-Huang, editor
- Published
- 1991
- Full Text
- View/download PDF
26. Enhanced fermentability of poplar by combination of alkaline peroxide pretreatment and semi-simultaneous saccharification and fermentation.
- Author
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Zhang, Liming, You, Tingting, Zhang, Lu, Yang, Haiyan, and Xu, Feng
- Subjects
- *
FERMENTATION , *POPLARS , *CHEMICAL inhibitors , *ETHANOL as fuel , *ALKALINITY , *LIGNINS - Abstract
Highlights: [•] Ethanol productivity was improved by a combined AP pretreatment and SSSF process. [•] 64.9% of lignin was removed by AP pretreatment. [•] Ethanol yield was significantly increased from 12.8% to 63.1%. [•] SSSF generated fewer inhibitors than SSF. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. Alkaline Peroxide and Laccase Treatment for the Delignification of Ricinus Communis Biomass to Enhance Saccharification
- Author
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Narkhede Yogesh
- Subjects
Laccase ,biology ,Chemistry ,Ricinus ,Biomass ,Alkaline peroxide ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,Pulp and paper industry ,biology.organism_classification ,01 natural sciences ,Hydrolysis ,0210 nano-technology ,0105 earth and related environmental sciences - Published
- 2018
28. Bagazo de sorgo dulce: una alternativa para la producción de etanol de segunda generación en Colombia (Parte I)
- Author
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Luis A. Rios, Mariana Peñuela Vásquez, Juan D. Peña, and John Múnera
- Subjects
deslignificación alcalina ,etanol ,Chemistry ,05 social sciences ,Alkaline peroxide ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Horticulture ,sorgo dulce ,lcsh:TA1-2040 ,Physical chemical ,0502 economics and business ,lcsh:Technology (General) ,Lignin ,lcsh:T1-995 ,lignocelulósico ,Bagasse ,lcsh:Engineering (General). Civil engineering (General) ,Sweet sorghum ,050203 business & management ,0105 earth and related environmental sciences - Abstract
Cada material lignocelulósico es un nuevo terreno por explorar, por tanto, la caracterización físico-química de estos materiales es un paso fundamental para el proceso de biotransformación. Se determinó la composición lignocelulósica del bagazo de sorgo dulce, encontrándose valores cercanos a los valores reportados en la literatura. Se estudiaron las tecnologías de pretratamiento, explosión con vapor, hidrólisis ácida suave, deslignificación alcalina, remojo con NH3, pretratamiento con amoniaco AFEX, ozonólisis y peróxido alcalino; encontrándose que la deslignificación alcalina con NaOH es la mejor opción para pretratar este sustrato. Se disminuyó el contenido de lignina en un 52% y se obtuvo una productividad a etanol de 0,87 g/L h, lo cual equivale a un rendimiento de 114 L de etanol/Ton bagazo de sorgo dulce seco pretratado.
- Published
- 2017
29. Two stages of treatments for upgrading bleached softwood paper grade pulp to dissolving pulp for viscose production.
- Author
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Wang, Haisong, Pang, Bo, Wu, Kejia, Kong, Fangong, Li, Bin, and Mu, Xindong
- Subjects
- *
SOFTWOOD , *PAPER pulp , *VISCOSE , *CELLULASE , *PEROXIDES , *BIOPOLYMERS - Abstract
Highlights: [•] Paper grade pulp was upgraded to dissolving pulp by two stages of treatment. [•] EG-rich industrial cellulase was used for enzymatic treatment. [•] α-Cellulose content and viscosity can be adjusted by alkali peroxide treatment. [•] Reducing sugar in spent liquor can be recovered to generate value-added products. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Efficient Enzymatic Hydrolysis of Bamboo by Pretreatment with Steam Explosion and Alkaline Peroxide.
- Author
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Yang Xing, Hailong Yu, Liwei Zhu, and Jianxin Jiang
- Subjects
- *
HYDROLYSIS , *BAMBOO , *STEAM , *ALKALINE solutions , *HEMICELLULOSE , *SOLUBILIZATION , *X-ray photoelectron spectroscopy , *POLYMERIZATION - Abstract
A combination of steam explosion (SE) and alkaline peroxide (AP) used to pretreat bamboo was investigated. Steam explosion at 224 °C for 4 min was applied to bamboo, and the pretreated bamboo was delignified by alkaline peroxide. Enzymatic hydrolysis was compared in the pretreated samples. Steam pretreatment led to remarkable hemicellulose solubilization (63.2%). Lignin solubilization (93.1%) was achieved by alkaline peroxide treatment of steam-pretreated bamboo at 80 °C for 1 h in 0.88% (v/v) H2O2, whereas only 33.4% of lignin was solubilized when using raw bamboo. Pretreatment methods resulted in a low degree of polymerization and increased hydrolysis of cellulose. A maximum glucose yield of 90.5% was achieved with a combined steam explosion and alkaline peroxide pretreatment. The surface structure of treated bamboo and the adsorption of enzyme on the substrate were characterized by X-ray photoelectron spectroscopy. Delignification decreased enzyme adsorption and increased enzymatic conversion. SEM analyses indicated that SE-AP pretreatment disrupted lignin networks and exposed crystalline cellulose in bamboo more effectively than SE or AP pretreatment alone. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
31. Chemical Evaluation of Eumelanin Maturation by ToF-SIMS and Alkaline Peroxide Oxidation HPLC Analysis
- Author
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Shosuke Ito, Peter Sjövall, Johan Lindgren, Martin Jarenmark, and Kazumasa Wakamatsu
- Subjects
principal component analysis ,Spectrometry, Mass, Secondary Ion ,Alkaline peroxide ,Article ,Catalysis ,lcsh:Chemistry ,eumelanin ,Inorganic Chemistry ,Melanin ,Pigment ,chemistry.chemical_compound ,stomatognathic system ,Animals ,Molecule ,Animal body ,Physical and Theoretical Chemistry ,Hydrogen peroxide ,lcsh:QH301-705.5 ,Molecular Biology ,Chromatography, High Pressure Liquid ,Spectroscopy ,Melanins ,time-of-flight secondary ion mass spectrometry ,Hplc analysis ,integumentary system ,Fossils ,Pigmentation ,maturation ,Chemistry ,Organic Chemistry ,social sciences ,General Medicine ,Peroxides ,Computer Science Applications ,Secondary ion mass spectrometry ,alkaline hydrogen peroxide oxidation ,lcsh:Biology (General) ,lcsh:QD1-999 ,visual_art ,Biophysics ,visual_art.visual_art_medium ,sense organs ,Oxidation-Reduction ,Biomarkers - Abstract
Residual melanins have been detected in multimillion-year-old animal body fossils, however, confident identification and characterization of these natural pigments remain challenging due to loss of chemical signatures during diagenesis. Here, we simulate this post-burial process through artificial maturation experiments using three synthetic and one natural eumelanin exposed to mild (100 °, C/100 bar) and harsh (250 °, C/200 bar) environmental conditions, followed by chemical analysis employing alkaline hydrogen peroxide oxidation (AHPO) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Our results show that AHPO is sensitive to changes in the melanin molecular structure already during mild heat and pressure treatment (resulting, e.g., in increased C-C cross-linking), whereas harsh maturation leads to extensive loss of eumelanin-specific chemical markers. In contrast, negative-ion ToF-SIMS spectra are considerably less affected by mild maturation conditions, and eumelanin-specific features remain even after harsh treatment. Detailed analysis of ToF-SIMS spectra acquired prior to experimental treatment revealed significant differences between the investigated eumelanins. However, systematic spectral changes upon maturation reduced these dissimilarities, indicating that intense heat and pressure treatment leads to the formation of a common, partially degraded, eumelanin molecular structure. Our findings elucidate the complementary nature of AHPO and ToF-SIMS during chemical characterization of eumelanin traces in fossilized organismal remains.
- Published
- 2020
32. The Effect of Alkaline Peroxide Pre-Treatment on Properties of Peanut Shell Powder Filled Recycled Polypropylene Composites
- Author
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Hanafi Ismail, Nor Fasihah Zaaba, and Mariatti Jaafar
- Subjects
Pre treatment ,Materials science ,Polypropylene composites ,Shell (structure) ,Alkaline peroxide ,Composite material - Published
- 2017
33. The effect of overnight storage conditions on complete denture colonization by Candida albicans and dimensional stability: A systematic review
- Author
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Tyler V. Verhaeghe, Chris C.L. Wyatt, and Nesrine Z. Mostafa
- Subjects
biology ,Denture, Complete ,business.industry ,medicine.medical_treatment ,Acrylic Resins ,Dentistry ,Alkaline peroxide ,030206 dentistry ,Controlled studies ,biology.organism_classification ,Peroxides ,03 medical and health sciences ,0302 clinical medicine ,Dry storage ,Biofilms ,Inclusion and exclusion criteria ,Candida albicans ,medicine ,Research questions ,Colonization ,Oral Surgery ,Dentures ,Denture Cleansers ,business - Abstract
Statement of problem Overnight removal of complete dentures is recommended to reduce the incidence of denture stomatitis. The effect of overnight storage conditions is unclear. Purpose The purpose of this systematic review was to assess the effect of overnight storage conditions on complete denture colonization by Candida albicans and to explore the effect of overnight storage conditions on the dimensional stability of complete dentures. Material and methods Two electronic databases were searched through to November 2018. The terms “denture*”, “dental prosthes*”, “acrylic resin*”, “storage”, “nighttime”, “overnight”, “wet”, “dry”, “water*”, and “solution” were chosen. Articles meeting the inclusion criteria were selected. For both research questions, studies that did not store the dentures overnight or for a minimum of 8 hours were excluded. For the primary research question, studies that were not randomized controlled studies or comparative studies were excluded. Results The database search strategy resulted in a total of 159 potential studies. After screening titles and abstracts and applying the inclusion and exclusion criteria, 6 studies were retrieved for a full-text assessment. Hand searching was also performed. Four studies were included in the systematic review for the primary research question. Three studies were included for the secondary research question. A meta-analysis could not be performed because of variation in study design. Conclusions Cleaning of dentures before overnight storage helps reduce C. albicans colonization. If the dentures are not cleaned, the use of an alkaline peroxide–based cleaning tablet should be considered. Alternately, overnight dry storage is an option for reducing C. albicans colonization, with clinically insignificant changes to the dimensions of the complete denture. Storing dentures in water alone may promote C. albicans colonization.
- Published
- 2019
34. Co-production of functional xylo-oligosaccharides and fermentable sugars from corn stover through fast and facile ball mill-assisted alkaline peroxide pretreatment.
- Author
-
Zhang, Fulong, Lan, Wu, Li, Zengyong, Zhang, Aiping, Tang, Baoling, Wang, Huihui, Wang, Xiaoying, Ren, Junli, and Liu, Chuanfu
- Subjects
- *
CORN stover , *SWEET corn , *OLIGOSACCHARIDES , *XYLANS , *XYLANASES , *PEROXIDES , *HYDROGEN peroxide , *XYLOSE - Abstract
[Display omitted] • A ball-mill assisted alkaline peroxide pretreatment process was developed. • 70% of XOS alone with high yield of fermentable sugars was achieved. • The pretreatment process was environmental-friendly. • The mechanism of enhanced enzymatic digestibility by BAP pretreatment was revealed. The aim of this work was to develop a feasible ball mill-assisted alkaline peroxide pretreatment followed by stepwise hydrolysis to improve the yield of xylo -oligosaccharides (XOS) and fermentable sugars. The hydrogen peroxide charge, ball-milling time, and solid-to-liquid ratio affected the compositions, particle sizes, morphology, and crystallinity of the corn stover, directly improving the following hydrolytic efficiency. The optimal pretreatment was with 0.45 g/g (H 2 O 2 : substrate) and 1:3 solid-to-liquid ratio (w/v) for 1.0 h ball-milling, resulting in 84.29% delignification. Physicochemical properties of the pretreated samples were characterized and their correlations to the enzymatic hydrolysis were revealed. Compared with one-step cellulase hydrolysis, the two-step xylanase-cellulase hydrolysis of the pretreated corn stover showed significant advance in preparing XOS, producing 69.65% (on the base of xylan content in pretreated sample) of XOS, along with 20.55% xylose, 68.94% glucose, and 21.15% gluco -oligosaccharides. The yield of XOS was 2–7 times higher than those in previous studies. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
35. PERBANDINGAN KEKERASAN RESIN AKRILIK TIPE HEAT CURED PADA PERENDAMAN LARUTAN DESINFEKTAN ALKALIN PEROKSIDA DENGAN EKSTRAK SELEDRI (APIUM GRAVEOLENS L.) 75%)
- Author
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Dewi Puspitasari, Rizky Noor Anisyah, and Debby Saputera
- Subjects
Absorption of water ,Materials science ,biology ,Apium graveolens ,Alkaline peroxide ,biology.organism_classification ,Peroxide ,Indentation hardness ,lcsh:RK1-715 ,chemistry.chemical_compound ,chemistry ,acrylic resin, hardness, alkaline peroxide, celery ,Cleanser ,visual_art ,lcsh:Dentistry ,visual_art.visual_art_medium ,Composite material ,Acrylic resin ,Apium ,Nuclear chemistry - Abstract
Background: One of the acrylic resins properties is the water absorption that affect on the hardness changes of the acry/ic resins. This /aboratory experiments studied disinfectant Alkaline peroxide and celery (Apium graveolens L.) extract 75% effect on the hardness changes of acry/ic denture base resins materia/. Purpose: This study aims to determine the effect of immersion denture cleanser alkalin peroxide and celery (Apium graveolens L.) extract 75% of the hardness acrylic resin.Methods: The study a pure experimental study with posttest-only with control group design. The study was conducted by immersing heat cured acrylic samples of 30 mm of diameter and 5 mm of thickness in alkaline peroxide, ce/ery (Apium graveo/ens L.) extract 75% and aquades for 5 and 15 days. An Vickers Microhardness Testing Machine using the Vickers indentation technique with (50 gr load for 10s) were used for the hardness changes observationResults: The statistical test used One-way ANOVA and Bonferroni with 0.05 significance degree /eve/. The average va/ue of acry/ic hardness in a/ka/ine peroxide and celery extract 5 days 15.01 VHN and 15.37 VHN, 15 days 13.77 VHN and 14.07 VHN.Conclusion: The resu/t showed no significant difference hardness of acry/ic resins denture base plate after immersion in Alkaline peroxide and celery (Apium graveolens L.) extract 75% for 5 and 15 days.
- Published
- 2016
36. Processing of Lespedeza stalks by pretreatment with low severity steam and post-treatment with alkaline peroxide
- Author
-
Su, Zhaoqin, Bu, Lingxi, Zhao, Danqing, Sun, Runcang, and Jiang, Jianxin
- Subjects
- *
LESPEDEZA , *PLANT stems , *ALKALINE earth metals , *PLANT biomass , *HYDROLYSIS , *STEAM , *SCANNING electron microscopy - Abstract
Abstract: The steam pre-treatment with low severity preserves valuable biomass components, and further delignification with alkaline peroxide could improve hydrolysis. A combination of low severity steam pretreatment and alkaline peroxide post-treatment of Lespedeza stalks was investigated. The post-treatment of steam-pretreated Lespedeza stalks with alkaline peroxide significantly increased the cellulose content and changed the structure of the cellulose-rich fractions. A glucose yield of 503.5mgg−1 raw material from enzyme hydrolysis was obtained when the steam-pretreated material (184°C for 4min) was post-treated with 2% hydrogen peroxide at 60°C for 24h with a substrate concentration of 3.3%. Its hydrolysis yield is 88.8%, which is higher than that of samples processed by steam pretreatment alone (63.7%). The samples obtained by post-treatment with alkaline peroxide were found to have a smoother surface and looser structure in scanning electron microscopy images. The isolated lignin preparations had a yield range from 10.9 to 14.7 (% dry matter). The lignin was characterized by thermogravimetric analysis/differential thermal analysis, Fourier transform infrared spectroscopy, and gel permeation chromatography. Alkaline peroxide treatment increased the thermal stability of lignin, and decreased the amounts of all functional groups. Depolymerization and repolymerization occurred during the alkaline peroxide treatment. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
37. A COMPARISON BETWEEN THE EFFECTS OF OZONE AND ALKALINE PEROXIDE TREATMENTS ON TMP PROPERTIES AND SUBSEQUENT LOW CONSISTENCY REFINING.
- Author
-
Xue Feng Chang, Olson, James A., and Beatson, Rodger P.
- Subjects
- *
ALKALINE earth metals , *METAL refining , *OZONE , *ELECTRIC power consumption , *THERMOMECHANICAL properties of metals , *COMPARATIVE studies , *TENSILE strength - Abstract
As part of a program to reduce electrical energy consumption in the refining process, the effects of the ozone and alkaline peroxide treatments on fibre and handsheet properties, prior and subsequent to low consistency (LC) refining, were assessed and compared by applying different levels of ozone and a range of peroxide and alkali charges to a primary stage hemlock thermomechanical pulp (TMP). Both highly alkaline peroxide treatments and ozone treatments decreased the specific energy required for strong mechanical pulp. The improvement in pulp strength through alkaline peroxide treatment mainly resulted from pulp surface changes caused by generation of acid groups. The highly alkaline peroxide treatments significantly increased pulp brightness but did not promote the further fibrillation during the subsequent LC refining. On the other hand, ozone treatments provided tensile strength increases, along with small brightness enhancements for the dark hemlock TMP, and increased the tensile gains obtained through LC refining. The effects of ozone treatments on tensile strength before and after LC refining were the result of pulp surface modifications, fibre swelling, and loss of fibre wall integrity due to non-selective chemical attack. High levels of ozone treatment caused tear strength to decrease during subsequent LC refining. [ABSTRACT FROM AUTHOR]
- Published
- 2012
38. Oil palm bio-fiber-reinforced polypropylene composites: effects of alkali fiber treatment and coupling agents.
- Author
-
Suradi, S.S., Yunus, R.M., and Beg, M.D.H.
- Subjects
- *
POLYPROPYLENE , *OIL palm , *FIBROUS composites , *ALKALI metals , *ADHESION , *HEMICELLULOSE , *PHOTODEGRADATION , *MALEIC anhydride , *PEROXIDES , *FOURIER transform infrared spectroscopy - Abstract
The major challenge for natural fiber composites is their inherent poor adhesion between fiber and the matrix, high moisture absorption, and UV degradation. Lignin and hemicelluloses are the major composites of natural fiber which are responsible for UV degradation and moisture absorption, respectively. In this study, the lignocelluloses (oil palm empty fruit bunch) were treated with alkaline peroxide to separate lignin and hemicelluloses. Composites were produced with treated and untreated fibers using up to 45% fiber with polypropylene matrix using twin-screw extruder followed by injection molding. To improve the interfacial bonding, maleic anhydride grafted polypropylene (MAPP) was used as a coupling agent in the formulation. Properties of composites were evaluated using tensile testing, flexural testing, impact testing, SEM, and FTIR. The tensile, flexural, and impact properties were found to be improved with alkaline peroxide-treated fiber composites compared to untreated fiber composites. Addition of coupling agent (MAPP) also found to provide improved properties of composites. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
39. Utilization of pineapple stem juice to enhance enzyme-hydrolytic efficiency for sugarcane bagasse after an optimized pre-treatment with alkaline peroxide
- Author
-
Monte, J.R., Brienzo, M., and Milagres, A.M.F.
- Subjects
- *
HYDROLYSIS , *PINEAPPLE juice , *ENZYMES , *SUGARCANE , *BAGASSE , *PEROXIDES , *CELLULASE , *XYLANASES , *ESTERASES - Abstract
Abstract: The enzymatic hydrolysis of sugarcane bagasse was investigated by treating a peroxide–alkaline bagasse with a pineapple stem juice, xylanase and cellulase. Pre-treatment procedures of sugarcane bagasse with alkaline hydrogen peroxide were evaluated and compared. Analyses were performed using 24 factorial designs, with pre-treatment time, temperature, magnesium sulfate and hydrogen peroxide concentration as factors. The responses evaluated were the yield of cellobiose and glucose released from pretreated bagasse after enzymatic hydrolysis. The results show that the highest enzymatic conversion was obtained for bagasse using 2% hydrogen peroxide at 60°C for 16h in the presence of 0.5% magnesium sulfate. Bagasse (5%) was treated with pineapple stem extract, which contains mixtures of protease and esterase, in combination with xylanase and cellulase. It was observed that the amount of glucose and cellobiose released from bagasse increased with the mixture of enzymes. It is believed that the enzymes present in pineapple extracts are capable of hydrolyze specific linkages that would facilitate the action of digesting plant cell walls enzymes. This increases the amount of glucose and other hexoses that are released during the enzymatic treatment and also reduces the amount of cellulase necessary in a typical hydrolysis. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
40. Alkaline peroxide pretreatment for efficient enzymatic saccharification of bamboo
- Author
-
Yamashita, Yuya, Shono, Megumi, Sasaki, Chizuru, and Nakamura, Yoshitoshi
- Subjects
- *
PEROXIDES , *BAMBOO , *ETHANOL as fuel , *ENZYMATIC analysis , *HYDROGEN peroxide , *CHEMICAL processes - Abstract
Abstract: Bamboo is an alternative feedstock for the production of fine chemicals, such as fuel ethanol and lactic acid, because bamboo has a large amount of sugars. An effective pretreatment method for enzyme saccharification is required for the efficient production of these materials. Enzyme saccharification (48h) using a 35atm and 5min steam exploded bamboo produced 426 and 488mg/(g initial dry sample) of glucose and reducing sugar, respectively. In addition, pretreatments using 20atm and 5min steam explosion or mechanical milling for 5min followed by 10wt.% sodium hydroxide treatment at 121°C for 60min were attempted in order to enhance the digestibility of the holocellulose component. Both of these pretreatment methods had a large positive effect on the production of sugars by subsequent enzymatic hydrolysis. In particular, the maximum value of glucose production was obtained by the 20atm steam explosion and 10wt.% sodium hydroxide treatment. This produced 456mg/(g initial dry sample) of glucose and 460mg/(g initial dry sample) of reducing sugar. In comparison, the mechanical milling and 10wt.% sodium hydroxide treatment produced 383 and 485mg/(g initial dry sample) of glucose and reducing sugar, respectively. From these results, it was concluded that the pretreatment with 20atm steam explosion and 10wt.% sodium hydroxide treatment was the most effective pretreatment method for the production of glucose from bamboo by enzyme saccharification. However, since this pretreatment method requires the severe conditions of both high pressure and temperature steam explosion and high concentration sodium hydroxide, an alkaline peroxide pretreatment without a steam explosion and high concentration sodium hydroxide was also attempted. A comparatively large amounts of glucose and reducing sugar production, i.e. 399 and 568mg/(g initial dry sample), respectively, were obtained in 1%(v/v) hydrogen peroxide and 1wt.% sodium hydroxide treatment at 90°C for 60min. Therefore, it was concluded that alkaline peroxide pretreatment is an effective and environmentally friendly method for the enzyme saccharification of bamboo. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
41. Deconstructing recalcitrant Miscanthus with alkaline peroxide and electrolyzed water
- Author
-
Wang, Bin, Wang, Xiaojuan, and Feng, Hao
- Subjects
- *
MISCANTHUS , *PEROXIDES , *FOURIER transform infrared spectroscopy , *CELLULOSE fibers , *SOLUTION (Chemistry) , *WASTEWATER treatment , *WATER electrolysis , *HEMICELLULOSE , *ENZYMATIC analysis , *HYDROLYSIS - Abstract
Abstract: A two-stage pretreatment method was proposed and tested for deconstruction of recalcitrant Miscanthus. During a 1st pretreatment at 50°C, 1.0–4.0% alkaline peroxide solutions were used to partially remove hemicellulose and lignin. The remaining solids were subjected to a 2nd pretreatment at 121°C with electrolyzed water. Using 15 filter paper units of cellulase per gram cellulose, a digestibility of 95% was achieved by the two-stage method, which was higher than 81% obtained from a 1% H2SO4 pretreatment (200°C, 8min). A mass balance for the two-stage process showed that 63% hemicellulose and 64% lignin were removed from the Miscanthus samples after the 1st pretreatment. The Scanning Electron Microscopy images and Fourier Transform Infrared Spectroscopy spectra revealed that after the 1st pretreatment, crystalline cellulose fibers were partially exposed and the linkages between residual lignin and hemicellulose disappeared. After the 2nd pretreatment, cellulose fibers were completely exposed even with cracks developed. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
42. Simultaneous saccharification and fermentation of steam exploded wheat straw pretreated with alkaline peroxide
- Author
-
Chen, Hongzhang, Han, Yejun, and Xu, Jian
- Subjects
- *
WHEAT straw , *FERMENTATION , *PEROXIDES , *LIGNOCELLULOSE , *BIOCHEMICAL engineering , *ALCOHOL , *CROP residues - Abstract
Abstract: The cellulose content of substrate is one of the most important factors for ethanol production from lignocellulose. To increase the cellulose content of substrate and ethanol yield in simultaneous saccharification and fermentation (SSF), a pretreatment method coupling steam explosion with alkaline peroxide for wheat straw was studied. After the complex pretreatment, the cellulose content in wheat straw increased from 31.5% to 67.2%. In the hydrolysate of wheat straw pretreated with the complex method and steam explosion, the glucose concentration was 110.9g/L and 67.8g/L, respectively. The optimal conditions for SSF were 40°C, 120h, cellulase loading 40FPU/(g wheat straw), yeast inoculum 10% (v/v) and substrate concentration 16.7% (w/v). Under the optimal conditions, the total ethanol concentration in SSF of wheat straw pretreated with steam explosion and alkaline peroxide reached 51.5g/L, and an overall yield of 81.1% was obtained. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
43. Comparative Study of Hemicelluloses Isolated with Alkaline Peroxide from Lignocellulosic Materials.
- Author
-
Sun, J. X., Mao, F. C., RunCang Sun, and Sun, X. F.
- Subjects
- *
HEMICELLULOSE , *PEROXIDES , *LIGNOCELLULOSE , *LIGNINS , *MAGNETIC resonance - Abstract
Treatment of dewaxed oil palm frond fiber; fast-growing poplar wood; maize stems; and barley, wheat, rice, and rye straws with 2.0% H2O2 at pH 11.6 for 16 hr at 45°C solubilized 85.7%, 49.5%, 78.2%, 79.7%, 87.1%, 92.7%, and 79.4% of the original hemicelluloses and 72.1%, 24.9%, 87.3%, 70.9%, 85.7%, 88.6%, and 89.8% of the original lignin, respectively. The results indicated that hydrogen peroxide at pH 11.6 had a significant effect on the release of hemicelluloses and delignification from oil palm frond fiber and cereal straws such as maize stems and barley, wheat, rice, and rye straws under the condition used. All the hemicellulosic preparations were much lighter in color and had relatively lower amounts of associated lignin than those obtained using traditional alkaline extraction in the absence of peroxide from the corresponding lignified materials. Xylose is the dominant sugar component in the hemicellulosic preparations isolated from oil palm frond fiber, fast-growing poplar wood, maize stems, and barley, wheat and rye straws, whereas the hemicelluloses obtained from rice straw are rich in glucose and xylose. The seven hemicellulosic samples were also studied by fourier transform infrared(FT-IR} and 1H- and 13C-nuclear magnetic resonance(NMR) spectroscopy, gel permeation chromatography(GPC), and thermal analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
44. Fractional extraction and structural characterization of sugarcane bagasse hemicelluloses
- Author
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Sun, J. X., Sun, X. F., Sun, R. C., and Su, Y. Q.
- Subjects
- *
WOOD chemistry , *SUGAR by-products , *HEMICELLULOSE , *LIGNINS , *SUGAR crops - Abstract
Over 90% of the original hemicelluloses in the cell walls of bagasse were sequentially extracted with distilled water, 0.5 M NaOH, 0.5, 1.0, 1.5, 2.0 and 3.0% H2O2 at pH 11.5, and 2.0 M NaOH at 55 °C for 2 h. Meanwhile, the successive treatments also released 89.0% of the original lignin. Chemical composition, physico-chemical properties, and structures of the eight hemicelluloses were elucidated by a combination of sugar analysis, nitrobenzene oxidation of bound lignin, molecular determination, Fourier transform infrared, and 1H and 13C NMR spectroscopy and thermal analysis and the results are reported. The results showed that the sequential treatments were very effective on the fractionation of hemicelluloses from bagasse, and the extraction strength, such as alkali and H2O2 concentration, had a great influence on the chemical and structural features of the hemicelluloses, e.g. content of associated lignin and molecular weight. The hemicellulosic fraction, isolated with 0.5% H2O2 at pH 11.5 for 2 h under 55 °C, had a backbone of xylose residues with β-(1→4) linkages and were branched mainly through arabinofuranosyl and 4-O-methyl glucopyranosyl units. Ferulic and p-coumaric acids were found to be esterified to the hemicelluloses. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
45. Comparative study of hemicelluloses released during two-stage treatments with acidic organosolv and alkaline peroxide from Caligonum monogoliacum and Tamarix spp
- Author
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Geng, Z.C., Sun, R.C., Sun, X.F., and Lu, Q.
- Subjects
- *
HEMICELLULOSE , *TAMARISKS - Abstract
Two-stage treatments of Caligonum monogoliacum and Tamarix spp. with acidic organosolv and alkaline peroxide were performed. Pre-treatment with ethanol–H2O (60/40, v/v) under acid catalyst (0.2 N HCl) at 70 °C for 4 h released 18.7 and 17.8% hemicelluloses from dewaxed C. monogoliacum and Tamarix spp., respectively, Sequential treatment with 2% H2O2 at pH 11.5 for 16 h at 45 °C solubilized 26.2 and 26.5% hemicelluloses from pre-treated C. monogoliacum and Tamarix spp., respectively. Cellulose predominated in the insoluble residues, accounting for 36.7–37.8% of dry materials. It was found that the two alkaline peroxide soluble hemicellulosic preparations contained a much higher amount of xylose (74.1–77.3%) but lower in glucose (7.4–18.6%), galactose (3.0–8.3%), rhamnose (2.3–2.9%), mannose (0.8–2.7%), and arabinose (1.3–1.4%) than those of the two acidic organosolv soluble hemicellulosic fractions in which xylose (31.8–50.8%), glucose (21.4–30.3%), galactose (7.6–24.1%), and rhamnose (5.7–10.1%) were the major sugar components. The content of uronic acids was slightly higher in the two alkaline peroxide soluble hemicellulosic preparations (7.5–8.3%) than the two acidic organosolv soluble hemicellulosic fractions (5.0–6.5%). Furthermore, the studies showed that the two alkaline peroxide soluble hemicellulosic preparations were more linear and acidic, and had a large molecular mass (
M¯ w, 27,220–31,410 g mol−1) than the two acidic organosolv soluble hemicellulosic fractions (M¯ w, 13,820–18,380 g mol−1). Lignin content and its composition associated in the four isolated hemicelluloses were determined by alkaline nitrobenzene oxidation and monitored with HPLC. No significant differences in lignin content (5.94–9.82%) and its composition were found. Further comparative study of the four hemicellulosic preparations and two cellulosic fractions was carried by both degraded methods such as acid hydrolysis and thermal analysis and non-degradation techniques such as FT-IR and 13C-NMR spectroscopy. [Copyright &y& Elsevier]- Published
- 2003
- Full Text
- View/download PDF
46. Study of Alkaline Peroxide Mechanical Pulp Made from Pinus densiflora
- Author
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Ji-Young Lee, Hyegeong Nam, Dong-Hun Park, Su-Yeon Joo, Min-Seok Lee, Chul-Hwan Kim, and Sol Kwon
- Subjects
Waste management ,biology ,Chemical treatment ,Pulp (paper) ,Alkaline peroxide ,General Chemistry ,engineering.material ,Pulp and paper industry ,biology.organism_classification ,Peroxide ,chemistry.chemical_compound ,Pinus densiflora ,chemistry ,Sodium hydroxide ,Ultimate tensile strength ,Media Technology ,engineering ,General Materials Science ,Hydrogen peroxide - Abstract
http://dx.doi.org/10.7584/ktappi.2016.48.1.100Journal of Korea TAPPIVol. 48. No. 1, 2016, 100-110pISSN (Print): 0253-3200Printed in Korea • 경상대학교 농업생명과학대학 환경재료과학과/임산공학과(Dept. of Env. Material Sci., IALS, Gyeonsang National Uni-versity, 660-701, Korea)† 교신저자(Corresponding Author): E-mail: jameskim@gnu.ac.kr Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treat-ment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabi-lizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less require-ment of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hy-drogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at
- Published
- 2016
47. Recycled Polypropylene/Peanut Shell Powder Composites: Pre-Treatment of Lignin Using Alkaline Peroxide
- Author
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Hanafi Ismail, Mariatti Jaafar, and Nor Fasihah Zaaba
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Environmental Engineering ,Materials science ,Absorption of water ,Scanning electron microscope ,lcsh:Biotechnology ,Compression molding ,Bioengineering ,Young's modulus ,02 engineering and technology ,chemistry.chemical_compound ,symbols.namesake ,020401 chemical engineering ,lcsh:TP248.13-248.65 ,Ultimate tensile strength ,Recycled polypropylene ,Lignin ,Alkaline peroxide ,Lignin removal ,0204 chemical engineering ,Composite material ,Fourier transform infrared spectroscopy ,Waste Management and Disposal ,Polypropylene ,021001 nanoscience & nanotechnology ,Lignocellulosic ,chemistry ,symbols ,Peanut shell powder ,0210 nano-technology - Abstract
This study investigated the performance of recycled polypropylene (RPP)/peanut shell powder (PSP) composites with untreated PSP and treated PSP with alkaline peroxide. The RPP/PSP and RPP/PSP-H2O2 composites were prepared by melt mixing and compression molding at different PSP loadings (10 wt.% to 40 wt.%). The samples were characterized by processing properties, tensile properties, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and water absorption behavior. The treated PSP enhanced the stabilization torque, tensile strength, elongation at break, tensile modulus, and water absorption of RPP/PSP-H2O2 composites. FTIR spectra and SEM showed that the elimination of lignin content strongly influenced the fractured surface and chemical characteristics of the RPP/PSP-H2O2 composites.
- Published
- 2016
48. Pilot-Scale Investigation into the Effects of Alkaline Peroxide Pre-Treatments on Low-Consistency Refining of Primary Refined Softwood TMP
- Author
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James A. Olson, Xue Feng Chang, Antti Luukkonen, and Rodger P. Beatson
- Subjects
0106 biological sciences ,Environmental Engineering ,Softwood ,Alkaline peroxide treatment ,lcsh:Biotechnology ,Bioengineering ,Alkaline peroxide ,02 engineering and technology ,engineering.material ,01 natural sciences ,Peroxide ,Refining intensity ,Tensile strength ,chemistry.chemical_compound ,010608 biotechnology ,Energy saving ,lcsh:TP248.13-248.65 ,Ultimate tensile strength ,Specific energy ,Composite material ,Waste Management and Disposal ,Tear resistance ,Pulp (paper) ,Fibre cutting ,TMP ,021001 nanoscience & nanotechnology ,Alkali metal ,Pulp and paper industry ,chemistry ,Low-consistency refining ,Acid group generation ,engineering ,0210 nano-technology - Abstract
Primary refined coarse softwood thermomechanical pulp was treated with alkaline peroxide prior to low-consistency (LC) refining. The effects of the pre-treatments on pulp quality, refinability, and electrical energy consumption were assessed. Four pre-treatments were conducted with alkali charges of 2.5 and 6% and peroxide charges of 3 and 4%. The pulps were refined to specific energies up to 600 kWh/t by multiple passes through an LC refiner at intensities of 90 and 150 kWh/t. It was found that alkaline peroxide treatments increased tear strength and protected the fibre from cutting, especially during high intensity refining below a specific energy of 300 kWh/t. Treatment with 6% NaOH and 4% or 3% H2O2 led to lower brightness gains and scattering coefficients but increased the tensile strength index by 31%, potentially lowering the total electrical energy required to achieve strong pulp. The enhancement of tensile strength caused by the highly alkaline peroxide mostly resulted from increased bonding, which was attributable to acid group generation rather than the promotion of further fibrillation during LC refining.
- Published
- 2016
49. Fractional and structural characterization of hemicelluloses isolated by alkali and alkaline peroxide from barley straw
- Author
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Sun, R.C. and Sun, X.F.
- Subjects
- *
HEMICELLULOSE , *LIGNINS - Abstract
Eight hemicellulosic fractions were obtained by sequential treatment of dewaxed barley straw with 0.1 M NaOH at 45 °C for 3 h, 0.25, 0.5, 1.0, 1.5, 2.0, and 3.0% H2O2 at 45 °C for 3 h at pH 11.5, and 10% KOH–1% Na2B4O7·10H2O at 28 °C for 15 h under continuous agitation. The yields of the fractions were 8.0, 3.1, 3.3, 3.3, 2.2, 2.0, 2.0, and 9.9%, respectively, of the initial amount of barley straw, corresponding to the dissolution of 21.6, 8.4, 8.9, 8.9, 5.9, 5.4, 5.4, and 26.7% of the original hemicelluloses. Meanwhile, the successive treatment also solubilized 29.1, 15.8, 14.6, 10.8, 4.5, 3.2, 2.7, and 3.7% of the original lignin, respectively. This sequential extraction together resulted in dissolution of 91.1% of the original hemicelluloses and 84.8% of the original lignin. The 0.1 M NaOH-soluble hemicellulosic fraction contained mainly xylose, glucose, and arabinose, 44.2, 15.7, and 15.2%, respectively, while the 10% KOH–1% Na2B4O7·10H2O-soluble fraction predominated in xylose, 75.0%. The six alkaline peroxide-soluble fractions were composed of 50.3–54.4% xylose, 14.7–16.9% arabinose, 6.8–10.7% glucose, 6.8–8.5% glucuronic acid or 4-O-methyl-d-glucuronic acid, 0.4–1.5% mannose, and 0.3–1.2% rhamnose. All the hemicellulosic fractions contained substantial amounts of glucuronoarabinoxylans and noticeable quantities of β-glucans. In comparison, the six hemicellulosic fractions, isolated with alkaline peroxide, had much higher molecular weights (56,890–63,810 g mol−1) than those of the two hemicellulosic preparations (28,000–29,080 g mol−1), isolated with alkali in the absence of hydrogen peroxide. The thermal stability of the hemicelluloses increased with an increment of their molar mass. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
50. Structural and physico-chemical characterization of lignins solubilized during alkaline peroxide treatment of barley straw.
- Author
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Sun, R.C., Sun, X.F., Fowler, P., and Tomkinson, J.
- Subjects
- *
ALKALIES , *PEROXIDES , *BARLEY - Abstract
In this paper, the seven acid-insoluble lignin preparations from barley straw were first extracted with alkaline hydrogen peroxide in order to study how the delignification and degradation of the lignin is influenced by aqueous 1.5% H
2 O2 extractant to straw ratios. The results showed that treatment of dewaxed barley straw with 1.5% H2 O2 at45 ° C for 14 h (pH 12.0) under the extractant to straw ratios of 10:1, 13:1, 15:1, 18:1, 20:1, 25:1, and 30:1 resulted in dissolution of 65.8%, 68.4%, 68.4%, 69.0%, 69.7%, 71.6%, and 72.3% of the original lignin and 78.7%, 79.8%, 82.3%, 83.4%, 84.8%, 85.3%, and 85.3% of the original hemicelluloses, respectively. The degraded seven lignin samples were analyzed with respect to their chemical compositions, content of chemically linked polysaccharides, molecular weights and structural changes. It was found that the alkaline peroxide treatment under the conditions given led to a noticeable increase in a amount of carboxyl groups due to the oxidation. The results from13 C-NMR analyses showed that the treatment was extremely effective for isolation of highly pure lignins from the straw, and the treatment under the conditions used did not affect the overall structure of lignin. Theβ -O-4 ether bond andβ –β carbon–carbon linkage were found to be the major linkages between lignin units. Hydroxycinnamic acids, such as p-coumaric and ferulic acids, appeared to be strongly linked to lignin molecules, in which p-coumaric acid was found to be bonded to lignin by ester linkage, while ferulic acid was linked by its phenolic group via ether bond to lignin and also principally linked by its carboxyl group via ester bond to lignin and/or hemicelluloses. [Copyright &y& Elsevier]- Published
- 2002
- Full Text
- View/download PDF
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