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Lujia Han - One of the best experts on this subject based on the ideXlab platform.
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Effect of Ultrafine Grinding Pretreatment on the Cellulose Fibers and Nanocrystals from Wheat Straw
Journal of Biobased Materials and Bioenergy, 2020Co-Authors: Chongfeng Gao, Yang Zhang, Yaoyao Cao, Weihua Xiao, Lujia HanAbstract:To investigate the effect of Ultrafine Grinding pretreatment on the isolation of wheat straw cellulose fibers and nanocrystals, wheat straw at cellular scale (50–30 m) were produced with different Ultrafine Grinding time prior to extract cellulose fibers and nanocrystals. Cellulose fibers were obtained by 4% sodium hydroxide and alkaline hydrogen peroxide treatment from Ultrafine ground wheat straw. Morphological changes were observed using scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectroscopy showed the removal of non-cellulosic components and the rearrangement of hydrogen bonds in cellulose. X-ray diffraction (XRD) analysis revealed the decrease of crystalline index with Grinding time prolonged and the formation of cellulose II in alkali treated 8.0 h Ultrafine ground wheat straw. Cellulose nanocrystals were produced from these cellulose fibers using 64% sulfuric acid hydrolysis treatment. Morphological examination through atomic force microscope (AFM) showed that the length of rod-like CNCs decreased with prolonged Ultrafine Grinding time in 2.0 h and then increased due to the formation of cellulose II.
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Understanding the synergistic effect and the main factors influencing the enzymatic hydrolyzability of corn stover at low enzyme loading by hydrothermal and/or Ultrafine Grinding pretreatment.
Bioresource technology, 2018Co-Authors: Haiyan Zhang, Guangqun Huang, Zengling Yang, Lujia HanAbstract:Abstract A thorough assessment of the microstructural changes and synergistic effects of hydrothermal and/or Ultrafine Grinding pretreatment on the subsequent enzymatic hydrolysis of corn stover was performed in this study. The mechanism of pretreatment was elucidated by characterizing the particle size, specific surface area (SSA), pore volume (PV), average pore size, cellulose crystallinity (CrI) and surface morphology of the pretreated samples. In addition, the underlying relationships between the structural parameters and final glucose yields were elucidated, and the relative significance of the factors influencing enzymatic hydrolyzability were assessed by principal component analysis (PCA). Hydrothermal pretreatment at a lower temperature (170 °C) combined with Ultrafine Grinding achieved a high glucose yield (80.36%) at a low enzyme loading (5 filter paper unit (FPU)/g substrate) which is favorable. The relative significance of structural parameters in enzymatic hydrolyzability was SSA > PV > average pore size > CrI/cellulose > particle size. PV and SSA exhibited logarithmic correlations with the final enzymatic hydrolysis yield.
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A novel film–pore–surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Lujia HanAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
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Changes to the physicochemical characteristics of wheat straw by mechanical Ultrafine Grinding
Cellulose, 2014Co-Authors: Yang Yang, Weihua Xiao, Lujia HanAbstract:To investigate changes on the physico- chemical characteristics of wheat straw by mechanical Ultrafine Grinding, wheat straw powders of four different particle sizes and distributions were produced using a sieve-based Retsch ZM100 grind mill and CJM-SY-B Ultrafine vibration grind mill. Changes on the microstructure and physicochemical characteris- tics of the different powders were assessed by scanning electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy, Fourier transform infra- red spectroscopy, thermogravimetric analysis and relevant standard laboratory analysis methods. Ultra- fine Grinding reduced the crystallite size and crystal- linity of the wheat straw. New surfaces were exposed on the Ultrafine powder with high levels of cellulose/ hemicelluloses components but there was no apparent change in chemical structure. Wheat straw powders were smaller in size but had a higher bulk density (from 0.19 to 0.54 g/mL) and angle of repose (from 46.02 to 55.61) and slide (from 37.26 to 41.00). The hydration properties (water-holding capacity and swelling capacity) decreased with reduction in particle size of the wheat straw. Both the sieve-based and Ultrafine powder exhibited a good ability to remove Pb 2? and Cd 2? and there was marginal improvement when using the Ultrafine powder. The thermal stability of the Ultrafine powder measured by thermogravimet- ric analysis decreased significantly because of the low cellulose crystallinity.
Haiyan Zhang - One of the best experts on this subject based on the ideXlab platform.
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Understanding the synergistic effect and the main factors influencing the enzymatic hydrolyzability of corn stover at low enzyme loading by hydrothermal and/or Ultrafine Grinding pretreatment.
Bioresource technology, 2018Co-Authors: Haiyan Zhang, Guangqun Huang, Zengling Yang, Lujia HanAbstract:Abstract A thorough assessment of the microstructural changes and synergistic effects of hydrothermal and/or Ultrafine Grinding pretreatment on the subsequent enzymatic hydrolysis of corn stover was performed in this study. The mechanism of pretreatment was elucidated by characterizing the particle size, specific surface area (SSA), pore volume (PV), average pore size, cellulose crystallinity (CrI) and surface morphology of the pretreated samples. In addition, the underlying relationships between the structural parameters and final glucose yields were elucidated, and the relative significance of the factors influencing enzymatic hydrolyzability were assessed by principal component analysis (PCA). Hydrothermal pretreatment at a lower temperature (170 °C) combined with Ultrafine Grinding achieved a high glucose yield (80.36%) at a low enzyme loading (5 filter paper unit (FPU)/g substrate) which is favorable. The relative significance of structural parameters in enzymatic hydrolyzability was SSA > PV > average pore size > CrI/cellulose > particle size. PV and SSA exhibited logarithmic correlations with the final enzymatic hydrolysis yield.
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quantitative characterization of enzyme adsorption and hydrolytic performance for Ultrafine Grinding pretreated corn stover
Bioresource Technology, 2017Co-Authors: Haiyan Zhang, Longjian Chen, Junbao Li, Minsheng LuAbstract:Abstract Quantitative analysis of enzyme adsorption and hydrolysis were performed for sieve-based Grinding corn stover (SGCS) and Ultrafine Grinding corn stover (UGCS) 1 with different enzyme consumptions. The UGCS presented significantly higher enzyme adsorption quantity (5.15 mg/g for UGCS, 1.33 mg/g for SGCS), higher glucose yield (49.75% for UGCS, 28.75% for SGCS) under 20 FPU/g and higher binding enzyme proportion (41.32% for UGCS, 10.64% for SGCS under 5 FPU/g) which can be attributed to the more accessible microstructure properties. The relationship between enzyme adsorption and hydrolytic production was directly proportional for SGCS (GY1 = 21.04 × AQ1 + 1.86 (R2 = 0.95)) while was exponential for UGCS (GY2 = 49.42 × (1 − e−0.57×AQ2) (R2 = 0.99)), 2 indicating that overmuch enzyme consumption was not advisable for UGCS at economical aspect.
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a novel film pore surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for Biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Minsheng Lu, Junbao LiAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
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A novel film–pore–surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Lujia HanAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
Junbao Li - One of the best experts on this subject based on the ideXlab platform.
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quantitative characterization of enzyme adsorption and hydrolytic performance for Ultrafine Grinding pretreated corn stover
Bioresource Technology, 2017Co-Authors: Haiyan Zhang, Longjian Chen, Junbao Li, Minsheng LuAbstract:Abstract Quantitative analysis of enzyme adsorption and hydrolysis were performed for sieve-based Grinding corn stover (SGCS) and Ultrafine Grinding corn stover (UGCS) 1 with different enzyme consumptions. The UGCS presented significantly higher enzyme adsorption quantity (5.15 mg/g for UGCS, 1.33 mg/g for SGCS), higher glucose yield (49.75% for UGCS, 28.75% for SGCS) under 20 FPU/g and higher binding enzyme proportion (41.32% for UGCS, 10.64% for SGCS under 5 FPU/g) which can be attributed to the more accessible microstructure properties. The relationship between enzyme adsorption and hydrolytic production was directly proportional for SGCS (GY1 = 21.04 × AQ1 + 1.86 (R2 = 0.95)) while was exponential for UGCS (GY2 = 49.42 × (1 − e−0.57×AQ2) (R2 = 0.99)), 2 indicating that overmuch enzyme consumption was not advisable for UGCS at economical aspect.
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a novel film pore surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for Biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Minsheng Lu, Junbao LiAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
Longjian Chen - One of the best experts on this subject based on the ideXlab platform.
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quantitative characterization of enzyme adsorption and hydrolytic performance for Ultrafine Grinding pretreated corn stover
Bioresource Technology, 2017Co-Authors: Haiyan Zhang, Longjian Chen, Junbao Li, Minsheng LuAbstract:Abstract Quantitative analysis of enzyme adsorption and hydrolysis were performed for sieve-based Grinding corn stover (SGCS) and Ultrafine Grinding corn stover (UGCS) 1 with different enzyme consumptions. The UGCS presented significantly higher enzyme adsorption quantity (5.15 mg/g for UGCS, 1.33 mg/g for SGCS), higher glucose yield (49.75% for UGCS, 28.75% for SGCS) under 20 FPU/g and higher binding enzyme proportion (41.32% for UGCS, 10.64% for SGCS under 5 FPU/g) which can be attributed to the more accessible microstructure properties. The relationship between enzyme adsorption and hydrolytic production was directly proportional for SGCS (GY1 = 21.04 × AQ1 + 1.86 (R2 = 0.95)) while was exponential for UGCS (GY2 = 49.42 × (1 − e−0.57×AQ2) (R2 = 0.99)), 2 indicating that overmuch enzyme consumption was not advisable for UGCS at economical aspect.
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a novel film pore surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for Biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Minsheng Lu, Junbao LiAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
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A novel film–pore–surface diffusion model to explain the enhanced enzyme adsorption of corn stover pretreated by Ultrafine Grinding
Biotechnology for biofuels, 2016Co-Authors: Haiyan Zhang, Longjian Chen, Lujia HanAbstract:Ultrafine Grinding is an environmentally friendly pretreatment that can alter the degree of polymerization, the porosity and the specific surface area of lignocellulosic biomass and can, thus, enhance cellulose hydrolysis. Enzyme adsorption onto the substrate is a prerequisite for the enzymatic hydrolysis process. Therefore, it is necessary to investigate the enzyme adsorption properties of corn stover pretreated by Ultrafine Grinding. The Ultrafine Grinding pretreatment was executed on corn stover. The results showed that Ultrafine Grinding pretreatment can significantly decrease particle size [from 218.50 μm of sieve-based Grinding corn stover (SGCS) to 17.45 μm of Ultrafine Grinding corn stover (UGCS)] and increase the specific surface area (SSA), pore volume (PV) and surface composition (SSA: from 1.71 m2/g of SGCS to 2.63 m2/g of UGCS, PV: from 0.009 cm3/g of SGCS to 0.024 m3/g of UGCS, cellulose surface area: from 168.69 m2/g of SGCS to 290.76 m2/g of UGCS, lignin surface area: from 91.46 m2/g of SGCS to 106.70 m2/g of UGCS). The structure and surface composition changes induced by Ultrafine Grinding increase the enzyme adsorption capacity from 2.83 mg/g substrate of SGCS to 5.61 mg/g substrate of UGCS. A film–pore–surface diffusion model was developed to simultaneously predict the enzyme adsorption kinetics of both the SGCS and UGCS. Satisfactory predictions could be made with the model based on high R 2 and low RMSE values (R 2 = 0.95 and RMSE = 0.16 mg/g for the UGCS, R 2 = 0.93 and RMSE = 0.09 mg/g for the SGCS). The model was further employed to analyze the rate-limiting steps in the enzyme adsorption process. Although both the external-film and internal-pore mass transfer are important for enzyme adsorption on the SGCS and UGCS, the UGCS has a lower internal-pore resistance compared to the SGCS. Ultrafine Grinding pretreatment can enhance the enzyme adsorption onto corn stover by altering structure and surface composition. The film–pore–surface diffusion model successfully captures features on enzyme adsorption on Ultrafine Grinding pretreated corn stover. These findings identify wherein the probable rate-limiting factors for the enzyme adsorption reside and could, therefore, provide a basis for enhanced cellulose hydrolysis processes.
Hui Lin - One of the best experts on this subject based on the ideXlab platform.
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Ultrafine Grinding of fly ash with Grinding aids impact on particle characteristics of Ultrafine fly ash and properties of blended cement containing Ultrafine fly ash
Construction and Building Materials, 2015Co-Authors: Jihui Zhao, Dongmin Wang, Xueguang Wang, Shucong Liao, Hui LinAbstract:Abstract This paper presents the Ultrafine Grinding performance of fly ash with Grinding aids (GA) and effect of GA on the particle characteristics, pozzolanic reaction degree of Ultrafine fly ash (UFFA) and properties of blended cement containing UFFA. The experimental results indicate that GA can improve the particle characteristics of ground fly ash. The specific surface area of UFFA with 0.05 wt% GA is higher by 104 m 2 /kg than control sample. The particle size distribution of UFFA with GA becomes narrow and particle content of less than 16 μm is obviously increased. Additionally, the fluidity and loose bulk density of UFFA have also been improved. For pozzolanic reaction degree, 3-day, 7-day and 28-day hydration degree of UFFA with GA is increased by 1.2%, 2.3% and 4.6%, respectively; and 3-day, 7-day and 28-day activity index of UFFA with GA is also increased by 6%, 8% and 9%, respectively. For properties of blended cement containing UFFA, enhancement effect of UFFA with GA on the strength of blended cement containing 20 wt%, 30 wt% and 40 wt% fly ash are significant, and 3-day strength is increased by 12.6%, 6.6% and 6.6%, respectively, 28-day strength is increased by 6.5%, 9.3% and 10.5%, respectively. In this study, the hydration degree and microstructure of blended cement containing UFFA paste are also analyzed by SEM, XRD, IR and TG-DTA. The studies show that improvements such as hydration degree, products quantity, uniformity and compactness of products structure of blended cement containing UFFA are attributed to finer particle size and better particle size distribution caused by the addition of GA.
