Glass bead-catalyzed depolymerization of poplar wood lignin into low-molecular-weight products

2019 ◽  
Vol 43 (23) ◽  
pp. 9280-9288 ◽  
Author(s):  
Lei Pu ◽  
Xing Wang ◽  
Kaiping Shang ◽  
Qiping Cao ◽  
Si Gao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Water Treatment ◽  
Glass Bead ◽  
Subcritical Water ◽  
Treatment Method ◽  
Low Molecular Weight ◽  
Poplar Wood ◽  
Bead Catalyst

A kind of non-precious glass bead catalyst was prepared by a subcritical water treatment method for the depolymerisation of poplar lignin.

scholarly journals Structural Changes in Milled Wood Lignin (MWL) of Chinese Quince (Chaenomeles sinensis) Fruit Subjected to Subcritical Water Treatment

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 398
Author(s):  
Wen-Yue Wang ◽  
Zhao Qin ◽  
Hua-Min Liu ◽  
Xue-De Wang ◽  
Jing-Hao Gao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Water Treatment ◽  
Quantum Coherence ◽  
Structural Changes ◽  
31P Nmr ◽  
Subcritical Water ◽  
Water Extraction ◽  
Subcritical Water Extraction ◽  
Milled Wood Lignin ◽  
Chinese Quince

Subcritical water treatment has received considerable attention due to its cost effectiveness and environmentally friendly properties. In this investigation, Chinese quince fruits were submitted to subcritical water treatment (130, 150, and 170 °C), and the influence of treatments on the structure of milled wood lignin (MWL) was evaluated. Structural properties of these lignin samples (UL, L130, L150, and L170) were investigated by high-performance anion exchange chromatography (HPAEC), FT-IR, gel permeation chromatography (GPC), TGA, pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 2D-Heteronculear Single Quantum Coherence (HSQC) -NMR, and 31P-NMR. The carbohydrate analysis showed that xylose in the samples increased significantly with higher temperature, and according to molecular weight and thermal analysis, the MWLs of the pretreated residues have higher thermal stability with increased molecular weight. The spectra of 2D-NMR and 31P-NMR demonstrated that the chemical linkages in the MWLs were mainly β-O-4′ ether bonds, β-5′ and β-β′, and the units were principally G- S- H- type with small amounts of ferulic acids; these results are consistent with the results of Py-GC/MS analysis. It is believed that understanding the structural changes in MWL caused by subcritical water treatment will contribute to understanding the mechanism of subcritical water extraction, which in turn will provide a theoretical basis for developing the technology of subcritical water extraction.

scholarly journals Subcritical Water Extraction of Low-molecular-weight Phenolic Compounds from Oil Palm Biomass

2014 ◽  
Vol 48 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Fumio KAWAMURA ◽  
Nur Syahirah SAARY ◽  
Rokiah HASHIM ◽  
Othman SULAIMAN ◽  
Koh HASHIDA ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phenolic Compounds ◽  
Oil Palm ◽  
Subcritical Water ◽  
Water Extraction ◽  
Low Molecular Weight ◽  
Subcritical Water Extraction ◽  
Oil Palm Biomass

scholarly journals Assessing pre-adsorption time impact on ultrafiltration performance for surface water treatment

2017 ◽  
Vol 18 (3) ◽  
pp. 950-955
Author(s):  
Bo Gui ◽  
Qingqing Zhao ◽  
Junxia Liu ◽  
Zhihong Wang ◽  
Huaqiang Chu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Liquid Chromatography ◽  
Activated Carbon ◽  
Water Treatment ◽  
Surface Water ◽  
Membrane Fouling ◽  
Low Molecular Weight ◽  
Raw Water ◽  
Adsorption Time ◽  
Surface Water Treatment

Abstract This study was to assess the effect of powdered activated carbon (PAC) pre-adsorption time on ultrafiltration performance for surface water treatment. Experimental results demonstrated that membrane fouling could be mitigated by extending the pre-adsorption time. The molecular weight (MW) distribution of water samples was determined by liquid chromatography – organic carbon detector (LC-OCD) and results showed that the mechanism of PAC controlling fouling was attributed to a decrease in the low molecular weight (LMW) fraction of raw water via extending the pre-adsorption time. Fouling indexes (FIs) were used to evaluate membrane fouling potential and the results showed that polysaccharides (PS) and proteins (PN) were greatly responsible for membrane fouling. Therefore, prolonging the PAC pre-adsorption time and decreasing the PS and PN content in raw water are the main measurement for the alleviation of membrane fouling when PAC is used as the pretreatment in waterworks.

scholarly journals Algae-Laden Fouling Control by Gravity-Driven Membrane Ultrafiltration with Aluminum Sulfate-Chitosan: The Property of Floc and Cake Layer

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1990 ◽  
Author(s):  
Peng Du ◽  
Xing Li ◽  
Yanling Yang ◽  
Zhiwei Zhou ◽  
Xiaoyan Fan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Aluminum Sulfate ◽  
Membrane Surface ◽  
Treatment Method ◽  
Cake Layer ◽  
Important Approach ◽  
Gravity Driven ◽  
Parallel Tests

Gravity-driven membrane (GDM) ultrafiltration is a promising water treatment method due to its low energy consumption and low maintenance. However, the low stable permeability in algae-laden water treatment is currently limiting its wider application. With the ultimate goal of increasing permeability, the aim of this study was to evaluate the effect of a composite coagulant of aluminum sulfate-chitosan (AS-CS) on the GDM filtration performance. In parallel tests with a single AS coagulant and without pre-coagulation, the analysis of membrane fouling resistance and the membrane fouling mechanism were evaluated. The results indicated that the AS-CS/GDM system can alleviate 23.74% and 58.80% membrane fouling, respectively, compared with AS/GDM and the GDM system. The AS-CS/GDM system can effectively remove humic-like substances having a molecular weight (MW) of 3–100 kDa, resulting in removal of 98.32% of algae cells and removal of 66.25% of dissolved organic carbon; the AS-CS/GDM system thereby improved the concentration of attached biomass on the membrane surface with the stronger biodegradability of organic matters. The application of AS-CS pre-coagulation in the GDM process could enhance the proliferation of microorganisms and the removal of low molecular weight humic-like substances. Therefore, the AS-CS/GDM system is a potentially important approach for algae-laden water treatment.

Purification and removal of the low molecular weight fraction of polyDADMAC reduces N-nitrosodimethylamine formation during water treatment

2020 ◽  
Vol 6 (9) ◽  
pp. 2492-2498
Author(s):  
Ariel J. Atkinson ◽  
Natalia Fischer ◽  
Samantha Donovan ◽  
Justin Bartlett ◽  
Omar Alrehaili ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Water Treatment ◽  
Weight Fraction ◽  
Cationic Polymer ◽  
Low Molecular Weight

Residual organics in cationic polymer contribute disproportionately to NDMA formation, but can be removed through polymer purification.

scholarly journals Conversion and Hydrothermal Decomposition of Major Components of Mint Essential Oil by Small-Scale Subcritical Water Treatment

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1953
Author(s):  
Tai-Ying Chiou ◽  
Shiori Nomura ◽  
Masaaki Konishi ◽  
Chien-Sen Liao ◽  
Yasutaka Shimotori ◽  
...  
Keyword(s):  
Water Treatment ◽  
Essential Oil ◽  
Subcritical Water ◽  
Treatment Method ◽  
Small Scale ◽  
Thermal Stabilities ◽  
Flavor Components ◽  
Japanese Mint ◽  
Water Conditions ◽  
Oil Components

Thermal stabilities of four major components (l-menthol, l-menthone, piperitone, and l-menthyl acetate) of Japanese mint essential oil were evaluated via subcritical water treatment. To improve experimental throughput for measuring compound stabilities, a small-scale subcritical water treatment method using ampoule bottles was developed and employed. A mixture of the four major components was treated in subcritical water at 180–240 °C for 5–60 min, and then analyzed by gas chromatography. The results indicated that the order of thermal resistance, from strongest to weakest, was: l-menthyl acetate, l-menthol, piperitone, and l-menthone. In individual treatments of mint flavor components, subsequent conversions of l-menthyl acetate to l-menthol, l-menthol to l-menthone, l-menthone to piperitone, and piperitone to thymol were observed in individual treatments at 240 °C for 60 min. As the mass balance between piperitone and thymol was low, the hydrothermal decomposition of the components was considered to have occurred intensely during, or after the conversion. These results explained the degradation of mint essential oil components under subcritical water conditions and provided the basis for optimizing the extraction conditions of mint essential oils using subcritical water.

scholarly journals Investigation of the Creep Property of Fast-growing Poplar Wood Modified with Low Molecular Weight Resins

BioResources ◽  
2015 ◽  
Vol 11 (1) ◽  
Author(s):  
Kong Yue ◽  
Weiqing Liu ◽  
Zhangjing Chen ◽  
Xiaoning Lu ◽  
Weidong Lu
Keyword(s):  
Molecular Weight ◽  
Creep Property ◽  
Low Molecular Weight ◽  
Poplar Wood ◽  
Fast Growing

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

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