| 1. |
- Ruiz, Héctor A., et al.
(författare)
-
Severity factor kinetic model as a strategic parameter of hydrothermal processing (steam explosion and liquid hot water) for biomass fractionation under biorefinery concept
- 2021
-
Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524. ; 342
-
Forskningsöversikt (refereegranskat)abstract
- Hydrothermal processes are an attractive clean technology and cost-effective engineering platform for biorefineries based in the conversion of biomass to biofuels and high-value bioproducts under the basis of sustainability and circular bioeconomy. The deep and detailed knowledge of the structural changes by the severity of biomasses hydrothermal fractionation is scientifically and technological needed in order to improve processes effectiveness, reactors designs, and industrial application of the multi-scale target compounds obtained by steam explosion and liquid hot water systems. The concept of the severity factor [log10 (Ro)] established>30 years ago, continues to be a useful index that can provide a simple descriptor of the relationship between the operational conditions for biomass fractionation in second generation of biorefineries. This review develops a deep explanation of the hydrothermal severity factor based in lignocellulosic biomass fractionation with emphasis in research advances, pretreatment operations and the applications of severity factor kinetic model.
|
|
| 2. |
- Hu, Jing, et al.
(författare)
-
Hydrothermal preparation of boehmite-doped AgCl nanocubes and their characterization
- 2011
-
Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 65:11, s. 1531-1534
-
Tidskriftsartikel (refereegranskat)abstract
- A simple hydrothermal route to the preparation of the boehmite-doped AgCl nanocubes using AgNO3,AlCl3 center dot 6H(2)O and NaOH at 200 degrees C for 24 h is reported. The products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), UV-vis, thermogravimetric analysis (TGA), and differential thermal analysis (DTA). FE-SEM and TEM micrographs showed that the obtained boehmite-doped AgCl had nanocube-like morphology. The influence of heating temperature on the phase, microstructure, morphology, and thermal stability of the products were also investigated. UV-visible results indicated that the absorption edge moved to higher wavelength with the increasing heating temperature. These materials would be a promising material for photocatalyst applications.
|
|
| 3. |
- Jia, Ning, et al.
(författare)
-
Hydrothermal fabrication, characterization, and biological activity of cellulose/CaCO3 bionanocomposites
- 2012
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 88:1, s. 179-184
-
Tidskriftsartikel (refereegranskat)abstract
- Bionanocomposites with the combination of natural polymers and inorganic nanoparticles may induce unique properties and exhibit promising functions for different applications. Herein, we report a hydrothermal route to the preparation of cellulose/CaCO3 bionanocomposites using the cellulose solution. Ca(NO3)(2)center dot 4H(2)O and Na2SiO3 center dot 9H(2)O. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in NaOH-urea aqueous solution. The urea also acts as the CO32- source for the synthesis of CaCO3. The influences of several reaction parameters, such as the heating time, the heating temperature, and the types of additives on the products were investigated by X-ray powder diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, thermogravimetric analysis, and differential thermal analysis. The experimental results demonstrated that the hydrothermal conditions had an effect on the morphology of the bionanocomposites. Cytotoxicity experiments indicated that the cellulose/CaCO3 bionanocomposites had good biocompatibility, so that the bionanocomposites could be ideal candidate for practical biomedical applications.
|
|
| 4. |
- Jia, Ning, et al.
(författare)
-
Hydrothermal Synthesis and Characterization of Cellulose-Carbonated Hydroxyapatite Nanocomposites in NaOH-Urea Aqueous Solution
- 2010
-
Ingår i: Science of Advanced Materials. - : American Scientific Publishers. - 1947-2935 .- 1947-2943. ; 2:2, s. 210-214
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose-carbonated hydroxyapatite (CHA) nanocomposites with CHA nanostructures dispersed in the cellulose matrix have been successfully synthesized using microcrystalline cellulose, CaCl2, and NaH2PO4 in NaOH-urea aqueous solution by hydrothermal method. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in NaOH-urea aqueous solution. The effects of the hydrothermal heating time, the heating temperature, and cellulose concentration on the products were investigated. The XRD and FTIR results indicated that the obtained products were the cellulose CHA nanocomposites. The SEM micrographs showed the CHA particles were dispersed in the cellulose matrix. The TGA and DTA indicated the cellulose content in the cellulose-CHA nanocomposites decreased with the decreasing raw cellulose. The size of CHA in nanocomposites decreased with the increasing preparation temperature. The products were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG), differential thermal analysis (DTA), Fourier transform infrared spectrometry (FTIR), and scanning electron microscopy (SEM). This type of cellulose/CHA nanocomposites would be expected to be useful as novel biomedical material.
|
|
| 5. |
- Jia, Ning, et al.
(författare)
-
Microwave-assisted synthesis and characterization of cellulose-carbonated hydroxyapatite nanocomposites in NaOH-urea aqueous solution
- 2010
-
Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 64:20, s. 2223-2225
-
Tidskriftsartikel (refereegranskat)abstract
- We report the microwave-assisted synthesis of the cellulose-carbonated hydroxyapatite (CHA) nanocomposites with CHA nanostructures dispersed in the cellulose matrix by using the cellulose solution, CaCl2, and NaH2PO4. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in NaOH-urea aqueous solution. The influences of the heating time and cellulose concentration on the products were also investigated. The X-ray powder diffraction (XRD) and Fourier transform infrared spectrometry (FT-IR) results indicated that the obtained products were the cellulose-CHA nanocomposites. The scanning electron microscopy (SEM) micrographs showed the CHA nanostructures were dispersed in the cellulose matrix. The thermal stability of the cellulose-CHA nanocomposites in air was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). This method is simple, fast, low-cost and suitable for large-scale production of cellulose-based nanocomposites.
|
|
| 6. |
- Jia, Ning, et al.
(författare)
-
Synthesis and characterization of cellulose-silica composite fiber in ethanol/water mixed solvents
- 2011
-
Ingår i: BioResources. - 1930-2126. ; 6:2, s. 1186-1195
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose-silica composite fiber samples have been successfully synthesized using cellulose solution, tetraethoxysilane, and NH3 center dot H2O in ethanol/water mixed solvents at room temperature for 24 h. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in a solvent mixture of N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl). The effect of the tetraethoxysilane concentration on the product was investigated. The products were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), energy-dispersive X-ray spectrum (EDS), and cross polarization magic angle spinning (CP/MAS) solid state C-13-NMR. The morphology of the cellulose-silica composite fiber was investigated by SEM, while their composition was established from EDS measurements combined with the results of FT-IR spectral analysis and XRD patterns. The XRD, FT-IR and EDS results indicated that the obtained product was cellulose-silica composite fiber. The SEM micrographs showed that the silica particles were homogeneously dispersed in the cellulose fiber. The CP/MAS solid state C-13-NMR results indicated that the silica concentration had an influence on the crystallinity of the cellulose. This method is simple for preparation of cellulose-based composites.
|
|
| 7. |
- Jiang, Jian-xin, et al.
(författare)
-
Structural and thermal characterization of galactomannans from genus Gleditsia seeds as potential food gum substitutes
- 2011
-
Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 91:4, s. 732-737
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Seed galactomannans are preferred hydrocolloids since they are comparatively cheap, non-toxic, eco-friendly and non-polluting during production and application. Galactomannans from seeds of three species of Gleditsia, namely G. sinensis, G. microphylla and G. melanacantha, were characterized in terms of structural and thermal properties. RESULTS: Gleditsia polysaccharides were characterized using both chemical and chromatographic methods, as well as Fourier transform infrared, H-1 nuclear magnetic resonance (NMR) and C-13 NMR spectroscopy, and it was shown that they consist of D-mannopyranose and D-galactopyranose residues. The mannose/galactose (M/G) ratio of galactomannans was 3.25, 3.31 and 2.30, respectively. It was also found that these polysaccharides differ from one another in values of M-w, M-n and polydispersity. X-ray diffraction confirmed the amorphous nature of Gleditsia galactomannans, although G. sinensis galactomannan showed a high crystallinity. Thermal analysis of the galactomannans by differential scanning calorimetry illustrated that their endothermic peaks ranged from 290 to 320 degrees C. CONCLUSION: Gleditsia polysaccharides are neutral galactomannans. The higher value of M/G ratio from G. sinensis and G. microphylla indicates that their gums offer an excellent alternative for locus bean gum. (C) 2011 Society of Chemical Industry
|
|
| 8. |
- Li, Shu-Ming, et al.
(författare)
-
Microwave-assisted method for the synthesis of cellulose-based composites and their thermal transformation to Mn2O3
- 2013
-
Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 43, s. 751-756
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the synthesis of inorganic materials using cellulose as a template by thermal treatment of the precursor. Cellulose-based composites have been successfully fabricated by an efficient microwave-assisted method. The influences of heating time on the phases and shape of the precursor were investigated. Mn2O3 materials were obtained by thermal treatment of the precursor at 600 degrees C for 3 h in air. The morphology of cellulose composites was preserved after thermal transformation to form Mn2O3. The products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), energy-dispersive X-ray spectra (EDS). scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). A rapid microwave-assisted method with the thermal post-treatment provides a promising route for the fabrication of inorganic materials using natural polymer as a template.
|
|
| 9. |
- Li, Shu-Ming, et al.
(författare)
-
Rapid microwave-assisted preparation and characterization of cellulose-silver nanocomposites
- 2011
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 83:2, s. 422-429
-
Tidskriftsartikel (refereegranskat)abstract
- A simple rapid and efficient microwave-assisted synthesis of cellulose-silver nanocomposites with silver nanoparticles homogeneously dispersed in the cellulose matrix using cellulose solution AgNO3 and ascorbic acid in N N-dimethylacetamide (DMAc) is reported The cellulose solution was prepared by the dissolution of microcrystalline cellulose in a solvent system of lithium chloride (LiCl)/DMAc The effects of the microwave heating times and ascorbic acid concentration on the nanocomposites were investigated The microstructure size morphology and thermal properties of these nanocomposites were analyzed with X-ray diffraction (XRD) Fourier transform infrared (FT-IR) thermogravimetric analysis (TG) differential scanning calorimetric analysis (DSC) and scanning electron microscopy (SEM) The results revealed that the ascorbic acid concentration played an important role in the phase of the nanocomposites This work provided a promising way to prepare cellulose-silver nanocomposites with good dispersity.
|
|
| 10. |
- Li, Shu-Ming, et al.
(författare)
-
Synthesis of cellulose-calcium silicate nanocomposites in ethanol/water mixed solvents and their characterization
- 2010
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 80:1, s. 270-275
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose-calcium silicate nanocomposites with calcium silicate nanoparticles homogeneously dispersed in the cellulose matrix have been successfully synthesized using cellulose solution, Ca(NO3)(2)center dot 4H(2)O and Na2SiO3 center dot 9H(2)O in ethanol/water mixed solvents at room temperature for 24 h. The cellulose solution was previously prepared by the dissolution of cellulose in a solvent system of N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl). The feeding order had an influence on the morphology of the cellulose-calcium silicate nanocomposites and the size of the calcium silicate particles. The cellulose in nanocomposites showed cellulose type II crystalline structure. The products were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), Fourier transform infrared spectrometry (FT-IR), energy-dispersive X-ray spectra (EDS), and scanning electron microscopy (SEM).
|
|
