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Effect of Surface Active Pollutants on the Rate of Mass Transfer Controlled Corrosion of Reactors Used in Wastewater Treatment
Eman Radi Sadik,
Taghreed Zewail,
Abd El-Aziz Konsowa,
Mona Abd El-Latif,
Gomma Sedahmed
Issue:
Volume 4, Issue 5, September 2016
Pages:
92-97
Received:
22 July 2016
Accepted:
2 August 2016
Published:
9 September 2016
Abstract: The diffusion controlled corrosion of a cooling system composed of an array of vertical tubes attached to the inner wall of a fixed bed reactor containing plastic Raschig rings was studied by a rapid technique which involves the diffusion controlled dissolution of copper in acidified dichromate. Variables studied were solution velocity, Raschig rings diameter, vertical tube height and the presence of surface active agent. The present data were correlated by a dimensionless equation. The presence of surface active agents decreased the rate of mass transfer by an amount ranging from 7.5 to 36.2 depending on the operating conditions. Implications of the present results for the design and operation of built-in cooling systems of fixed bed reactors was highlighted. Also the possible use of the obtained equation in calculating the rate of heat transfer by analogy was discussed.
Abstract: The diffusion controlled corrosion of a cooling system composed of an array of vertical tubes attached to the inner wall of a fixed bed reactor containing plastic Raschig rings was studied by a rapid technique which involves the diffusion controlled dissolution of copper in acidified dichromate. Variables studied were solution velocity, Raschig rin...
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Kinetics and Mechanism of Permanganate Oxidation of Inositol in Perchloric and Sulfuric Acids Solutions
Ahmed Fawzy,
Ishaq A. Zaafarany,
Hatem M. Altass,
Moataz H. Morad,
Jabir Alfahemi
Issue:
Volume 4, Issue 5, September 2016
Pages:
98-104
Received:
29 August 2016
Accepted:
5 September 2016
Published:
24 September 2016
Abstract: The kinetics of oxidation of inositol (INOS) by permanganate ion in both perchloric and sulfuric acids solutions was studied using a spectrophotometric technique at a constant ionic strength of 1.0 mol dm-3 and at 25°C. In both acids, the reactions showed a first order dependence with respect to [permanganate], whereas the orders with respect to [INOS] were found to be less than unity. The effect of acids concentrations suggests that the reactions were acid-catalyzed with fractional-second order kinetics in [H+]. Variation of either ionic strength or dielectric constant of the medium had no effect significantly on the oxidation rates. The reactions mechanism adequately describing the kinetic results was proposed. In both acids, the main oxidation products of inositol were identified by spectral and chemical tools as the corresponding monoketone derivative, namely inosose. Under comparable experimental conditions, the oxidation rate in sulfuric acid was approximately three times higher than that in perchloric acid. Regarding to the second order rate constants of these reactions, the activation parameters have been evaluated and discussed.
Abstract: The kinetics of oxidation of inositol (INOS) by permanganate ion in both perchloric and sulfuric acids solutions was studied using a spectrophotometric technique at a constant ionic strength of 1.0 mol dm-3 and at 25°C. In both acids, the reactions showed a first order dependence with respect to [permanganate], whereas the orders with respect to [I...
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Kinetic Modeling of Multiple Adsorption of Heavy Metal Ions Using Activated Carbon from Nigerian Bamboo for Design of Adsorbers
Issue:
Volume 4, Issue 5, September 2016
Pages:
105-113
Received:
30 August 2016
Accepted:
10 September 2016
Published:
11 October 2016
Abstract: In this study, the kinetics modeling for design of adsorbers for multiple adsorption of heavy metal ions was carried out using activated carbon from waste Nigerian bamboo. The bamboo was cut into sizes, washed, dried and was carbonized at 350°C-500°C. It was then activated at 800°C using nitric acid. Simultaneous batch adsorption of different heavy metal ions (Cd2+, Ni2+, Pb2+, Cr3+,Cu2+and Zn2+) in same aqueous solution using activated carbon from Nigerian bamboo was carried out at different initial concentration till equilibrium was reached. In order to determine the mechanism of sorption for multiple adsorption of these heavy metals ions, the kinetic data were modeled using the pseudo first order, pseudo second order kinetic equations, and intra-particle diffusion models. The pseudo first order did not fit well into the kinetic data. The pseudo second order equation was the best applicable model to describe the sorption process. Hence the pseudo second order kinetic reaction is the rate controlling step with some intra particle diffusion taking place. An empirical model was also developed which can then be used for predicting and designing adsorber for the multiple removal of 99% heavy metal ions at any given initial heavy metal ions concentration and the adsorption time required for any multi-stage adsorption system using Nigerian Bamboo activated carbon.
Abstract: In this study, the kinetics modeling for design of adsorbers for multiple adsorption of heavy metal ions was carried out using activated carbon from waste Nigerian bamboo. The bamboo was cut into sizes, washed, dried and was carbonized at 350°C-500°C. It was then activated at 800°C using nitric acid. Simultaneous batch adsorption of different heavy...
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Deciphering Electron Shuttles for Bioremediation and Beyond
Bor-Yann Chen,
Chung-Chuan Hsueh
Issue:
Volume 4, Issue 5, September 2016
Pages:
114-121
Received:
16 October 2016
Published:
17 October 2016
Abstract: Electron shuttles (or redox mediators) are organic chemical(s) that can be reversibly oxidized and reduced to drive electron transport phenomena for energy extraction to support myriads of lives. Efficient energy recycling would provide economically-feasible route(s) to environmental remediation and cost-effective energy shuttling could optimize activities to sustain human health. Thus, using microbial fuel cells (MFCs) as operation strategy is economically-competitive for pollutant bioremediation. Considering reductive decolorization, accumulation of decolorized metabolites (DM) could significantly stimulate electron-transfer (ET) capabilities for dye degradation. In addition, model intermediate(s) with auxochromes (e.g., amino and hydroxyl substituent(s)-containing chemicals) could act as electron shuttles (ESs) to feedback stimulate MFC-assisted degradation. Moreover, quantitative assessment of simultaneous reductive decolorization and bioelectricity generation (SRD&BG) via MFCs indicated that ET capabilities of SRD&BG could be augmented more than 40-70% due to autocatalysis of DM. Apparently, MFC-aided bioremediation was promising to wastewater decolorization due to redox-mediating characteristics of DM. In addition, impedance method in bioelectrochemistry was technically plausible due to specific fingerprints of different genus-related microalgae or microorganisms. As several edible flora (EF) contained crucial compositions to human health (e.g., antioxidants- polyphenolic compounds, flavonoids), extracts of EF were very likely to show promising ET capabilities to augment performance of RD and/or BG. That is, such stimulating capabilities were possibly associated to antioxidant characteristics of chemical species in EF. Evaluation of ET-stimulating characteristics of EF could thus be an indicator to prescreen whether candidate species of EF could be feasible antioxidant(s) or ESs for human health. As all lives utilize energy as driving force for sustaining diverse metabolic functioning, bioelectrochemistry is evidently vital to the biological world. As UN report mentioned, bioenergy will be a major portion of renewable energy for the planet’s energy supply by 2050. Therefore, ESs would play a significant role of energy extraction not only for environmental remediation, but also human health.
Abstract: Electron shuttles (or redox mediators) are organic chemical(s) that can be reversibly oxidized and reduced to drive electron transport phenomena for energy extraction to support myriads of lives. Efficient energy recycling would provide economically-feasible route(s) to environmental remediation and cost-effective energy shuttling could optimize ac...
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High-Precision Repetitive Motion Control in Permanent Magnet Synchronous Motor Using a Periodic Adaptive Extended State Observer
Zhi Ren,
Wenjun Qiao,
Yang Liu,
Xiaohong Zhang,
Songtao Li,
Min Huang,
Yingdi Bao,
Gang Fang
Issue:
Volume 4, Issue 5, September 2016
Pages:
122-130
Received:
20 October 2016
Published:
20 October 2016
Abstract: This paper focuses on estimating and compensating the lumped disturbances in the repetitive motion control system of permanent magnet synchronous motor. A Periodic Adaptive Extended State Observer (PAESO) consisting of a normal Extended State Observer (ESO) and a refined ESO is proposed. The normal ESO is designed to capture the approximate range of the disturbances, and the refined ESO is developed to optimize the quantity of the estimated lumped disturbances by integrating real-time position tracking error. Based on PAESO, a hybrid controller, including a feedback branch and a feedforward branch, is presented to make the overall system stable and the position tracking error convergent towards zero. The effectiveness of the proposed PAESO is verified through three real-time experiments. Experimental results show that a high-precision tracking performance is obtained by the proposed PAESO.
Abstract: This paper focuses on estimating and compensating the lumped disturbances in the repetitive motion control system of permanent magnet synchronous motor. A Periodic Adaptive Extended State Observer (PAESO) consisting of a normal Extended State Observer (ESO) and a refined ESO is proposed. The normal ESO is designed to capture the approximate range o...
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Process Safety Knowledge Management in the Chemical Process Industry
Issue:
Volume 4, Issue 5, September 2016
Pages:
131-138
Received:
19 October 2016
Published:
20 October 2016
Abstract: Chemical process industry is a high risk industry which can result in catastrophic casualties, loss of properties, and environment damage. Process safety should always come first in the chemical process industry. Researchers have made great efforts to make the chemical process industry safer for people and the environment. Effective process safety management is the guarantee for process safety. Key elements of process safety management and risk based process safety are presented and discussed. Sometimes process safety knowledge is not utilized effectively in implementing process safety management. Knowledge and knowledge management are introduced. Various process safety knowledge sources are analyzed. A knowledge management framework is proposed to utilize process safety knowledge. With the proposed knowledge management framework, process safety knowledge can be used to prevent chemical accidents, mitigate the consequences, and reduce risk in the chemical process industry.
Abstract: Chemical process industry is a high risk industry which can result in catastrophic casualties, loss of properties, and environment damage. Process safety should always come first in the chemical process industry. Researchers have made great efforts to make the chemical process industry safer for people and the environment. Effective process safety ...
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