The Experts below are selected from a list of 20739 Experts worldwide ranked by ideXlab platform
P K Karlis - One of the best experts on this subject based on the ideXlab platform.
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thermal alkaline solubilization of waste activated sludge as a pre treatment stage for anaerobic digestion
Bioresource Technology, 2004Co-Authors: A G Vlyssides, P K KarlisAbstract:Abstract This work studied the Hydrolysis Kinetics and the solubilization of waste activated sludge under a medium range temperature (50–90 °C) and pH in the alkaline region (8–11), as a pretreatment stage for anaerobic digestion. The Hydrolysis rate for the solubilization of volatile suspended solids (VSS) followed a first-order rate. A linear polynomial Hydrolysis model was derived from the experimental results leading to a satisfactory correlation between the Hydrolysis rate coefficient, pH, and temperature. At pH 11 and a temperature of 90 °C the concentration of the VSS was 6.82%, the VSS reduction reached 45% within ten hours and at the same time the soluble COD was 70.000 mg/l and the total efficiency for methane production 0.28 l of CH4 per g of VSS loading.
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thermal alkaline solubilization of waste activated sludge as a pre treatment stage for anaerobic digestion
Bioresource Technology, 2004Co-Authors: A G Vlyssides, P K KarlisAbstract:This work studied the Hydrolysis Kinetics and the solubilization of waste activated sludge under a medium range temperature (50-90 degrees C) and pH in the alkaline region (8-11), as a pretreatment stage for anaerobic digestion. The Hydrolysis rate for the solubilization of volatile suspended solids (VSS) followed a first-order rate. A linear polynomial Hydrolysis model was derived from the experimental results leading to a satisfactory correlation between the Hydrolysis rate coefficient, pH, and temperature. At pH 11 and a temperature of 90 degrees C the concentration of the VSS was 6.82%, the VSS reduction reached 45% within ten hours and at the same time the soluble COD was 70.000 mg/l and the total efficiency for methane production 0.28 l of CH4 per g of VSS loading.
Jeffrey A Hubbell - One of the best experts on this subject based on the ideXlab platform.
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network formation and degradation behavior of hydrogels formed by michael type addition reactions
Biomacromolecules, 2005Co-Authors: And Andrew Metters, Jeffrey A HubbellAbstract:Hydrolytically labile poly(ethylene glycol)-based hydrogels are fabricated via a Michael-type addition reaction between unsaturated acrylate moieties and nucleophilic thiols. Although these gels offer the advantage of selective, in situ polymerization and potential as biocompatible matrixes for cell and protein encapsulation, a thorough understanding of the complex structure−property relationships that control the macroscopic behaviors of these cross-linked networks before and during hydrolytic degradation does not exist. Therefore, in this work, a novel theoretical model is presented to describe the formation and hydrolytic degradation of the step-polymerized gels. The model accounts for variations in Hydrolysis Kinetics as well as structural effects such as precursor functionality and the presence of primary cycles or other structural nonidealities that lower the cross-linking efficiency of the networks. Comparison of model predictions and experimental data validate this methodology for optimizing bioma...
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network formation and degradation behavior of hydrogels formed by michael type addition reactions
Biomacromolecules, 2005Co-Authors: And Andrew Metters, Jeffrey A HubbellAbstract:Hydrolytically labile poly(ethylene glycol)-based hydrogels are fabricated via a Michael-type addition reaction between unsaturated acrylate moieties and nucleophilic thiols. Although these gels offer the advantage of selective, in situ polymerization and potential as biocompatible matrixes for cell and protein encapsulation, a thorough understanding of the complex structure-property relationships that control the macroscopic behaviors of these cross-linked networks before and during hydrolytic degradation does not exist. Therefore, in this work, a novel theoretical model is presented to describe the formation and hydrolytic degradation of the step-polymerized gels. The model accounts for variations in Hydrolysis Kinetics as well as structural effects such as precursor functionality and the presence of primary cycles or other structural nonidealities that lower the cross-linking efficiency of the networks. Comparison of model predictions and experimental data validate this methodology for optimizing biomaterial design and reveal that structural nonidealities play a key role in determining the degradation behavior of real cross-linked systems. Decreasing precursor concentration and functionality during network formation generate high concentrations of network nonidealities that ultimately lead to higher initial swelling ratios and faster apparent rates of degradation.
Andrew J. Greaves - One of the best experts on this subject based on the ideXlab platform.
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alkali Hydrolysis Kinetics of 4 amino 4 fluorosulfonylazo benzene disperse dyes and their dyeing fastness properties
Dyes and Pigments, 2004Co-Authors: Joonseok Koh, Andrew J. Greaves, Jae Pil KimAbstract:Abstract The alkali-Hydrolysis Kinetics of a series of 4-amino-4′-fluorosulfonylazobenzene disperse dyes were investigated using HPLC, and their fastness properties on poly(ethyleneterephthalate) were examined. Most of the dyes showed a reasonable level of Hydrolysis (%) under relatively mild alkaline conditions and the dyes having more electron-accepting groups in the diazo component exhibited a lower rate of Hydrolysis. The use of fluorosulfonyl containing disperse dyes showed excellent dyeing fastness properties and offer the option of alkali clearance to achieve high wash fastness, replacing reductive clearing and sodium hydrosulfite in particular, which places a very high BOD on conventional disperse dyeing effluents and then generates aromatic amines.
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synthesis and application of an alkali clearable azo disperse dye containing a fluorosulfonyl group and analysis of its alkali Hydrolysis Kinetics
Dyes and Pigments, 2001Co-Authors: Andrew J. GreavesAbstract:An alkali-clearable azo disperse dye containing a fluorosulfonyl group was synthesised. 4-Fluorosulfonylaniline, which was used as the diazo component, was prepared from N-acetylsulfanilyl chloride and coupled with N,N-diethyl-m-toluidine. Pseudo first-order Kinetics were determined by analysis of the dye Hydrolysis under alkaline conditions using HPLC. The synthesised dye was also applied to poly(ethyleneterephthalate) and its dyeing and wash fastness properties examined.
Ping Wang - One of the best experts on this subject based on the ideXlab platform.
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hydrogen generation from solvolysis of sodium borohydride in ethylene glycol water mixtures over a wide range of temperature
RSC Advances, 2013Co-Authors: Dawei Zhuang, Hongbin Dai, Ping WangAbstract:A high-performance hydrogen generation system with fast Kinetics and a wide range of operational temperature is highly desirable for promoting the implementation of hydrogen fuel cell technology. In the present study, we report a comparative study of the hydrogen generation properties from the reactions between sodium borohydride (NaBH4) and ethylene glycol (EG), water (H2O) or their mixture. Our study found that the glycolysis Kinetics of NaBH4 is faster than the Hydrolysis Kinetics at moderate temperatures, but gets sluggish at low temperatures. As a solution, the combined usage of EG–water mixture as solvent and cobalt chloride (CoCl2) as a promoting additive enables the system to rapidly deliver H2 at low temperatures. A series of control experiments have been conducted to evaluate the hydrogen generation property dependence on EG concentration, CoCl2 amount and ratio of EG–H2O mixture to NaBH4. The reaction byproducts were characterized by powder X-ray diffraction and Fourier transform infrared spectroscopy techniques. Our study demonstrated a high-performance hydrogen generation system with a wide range of operational temperature, which may lay the foundation for developing practical hydrogen source for mobile/portable applications.
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hydrogen generation from sodium borohydride solution using a ruthenium supported on graphite catalyst
International Journal of Hydrogen Energy, 2010Co-Authors: Yan Liang, Hongbin Dai, Ping Wang, Huiming ChengAbstract:The catalyst with high activity and durability plays a crucial role in the hydrogen generation systems for the portable fuel cell generators. In the present study, a ruthenium supported on graphite catalyst (Ru/G) for hydrogen generation from sodium borohydride (NaBH(4)) solution is prepared by a modified impregnation method. This is done by surface pretreatment with NH(2) functionalization via silanization, followed by adsorption of Ru (III) ion onto the surface, and then reduced by a reducing agent. The obtained catalyst is characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Very uniform Ru nanoparticles with sizes of about 10 nm are chemically bonded on the graphite surface. The Hydrolysis Kinetics measurements show that the concentrations of NaBH4 and NaOH all exert considerable influence on the catalytic activity of Ru/G catalyst towards the Hydrolysis reaction of NaBH(4). A hydrogen generation rate of 32.3 L min(-1) g(-1) (Ru) in a 10 wt.% NaBH(4) + 5 wt.% NaOH solution has been achieved, which is comparable to other noble catalysts that have been reported. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.
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new insights into catalytic Hydrolysis Kinetics of sodium borohydride from michaelis menten model
Journal of Physical Chemistry C, 2008Co-Authors: Hongbin Dai, Yan Liang, Ping WangAbstract:Catalytic Hydrolysis Kinetics is a subject of great interest in the study of sodium borohydride (NaBH4)-based hydrogen generation system. In the present paper, we report our coupled experimental/model analysis studies on the catalytic Hydrolysis Kinetics of NaBH4 with the presence of Co-B catalyst. The effects of NaBH4 concentration and Co-B catalyst amount on the Hydrolysis Kinetics of NaBH4 were experimentally examined and analyzed in terms of the Michaelis-Menten model. It was found that the catalytic Hydrolysis reaction of NaBH4 follows first-order Kinetics at low NaBH4 concentration and zero-order Kinetics at high NaBH4 concentration. The Hydrolysis Kinetics is first-order with respect to catalyst amount. These findings provide valuable insights into the catalytic Hydrolysis Kinetics of NaBH4.
A G Vlyssides - One of the best experts on this subject based on the ideXlab platform.
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thermal alkaline solubilization of waste activated sludge as a pre treatment stage for anaerobic digestion
Bioresource Technology, 2004Co-Authors: A G Vlyssides, P K KarlisAbstract:Abstract This work studied the Hydrolysis Kinetics and the solubilization of waste activated sludge under a medium range temperature (50–90 °C) and pH in the alkaline region (8–11), as a pretreatment stage for anaerobic digestion. The Hydrolysis rate for the solubilization of volatile suspended solids (VSS) followed a first-order rate. A linear polynomial Hydrolysis model was derived from the experimental results leading to a satisfactory correlation between the Hydrolysis rate coefficient, pH, and temperature. At pH 11 and a temperature of 90 °C the concentration of the VSS was 6.82%, the VSS reduction reached 45% within ten hours and at the same time the soluble COD was 70.000 mg/l and the total efficiency for methane production 0.28 l of CH4 per g of VSS loading.
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thermal alkaline solubilization of waste activated sludge as a pre treatment stage for anaerobic digestion
Bioresource Technology, 2004Co-Authors: A G Vlyssides, P K KarlisAbstract:This work studied the Hydrolysis Kinetics and the solubilization of waste activated sludge under a medium range temperature (50-90 degrees C) and pH in the alkaline region (8-11), as a pretreatment stage for anaerobic digestion. The Hydrolysis rate for the solubilization of volatile suspended solids (VSS) followed a first-order rate. A linear polynomial Hydrolysis model was derived from the experimental results leading to a satisfactory correlation between the Hydrolysis rate coefficient, pH, and temperature. At pH 11 and a temperature of 90 degrees C the concentration of the VSS was 6.82%, the VSS reduction reached 45% within ten hours and at the same time the soluble COD was 70.000 mg/l and the total efficiency for methane production 0.28 l of CH4 per g of VSS loading.
