• Membrane and Water Treatment
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• 제9권2호
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• pp.79-85
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• 2018

In this work, batch adsorption of anionic dye acid green-25 (AG-25) from aqueous solution has been carried out at room temperature using anion exchange membrane (DF-120B) as a noval adsorbent. The effect of various experimental parameters such as contact time, membrane dosage, ionic strength and temperature on the adsorption of dye were investigated. Kinetic models namely pseudo-first-order, pseudo-second-order, Elovich, liquid film diffusion, Bangham and modified freundlich models were employed to evaluate the experimental data. Parameters like adsorption capacities, rate constant and related correlation coefficients for every model are calculated and discussed. It showed that adsorption of AG-25 onto DF-120B followed pseudo-first-order rate expression. Thermodynamic study indicates that adsorption of AG-25 onto DF-120B is an exothermic and spontaneous process.

• Membrane and Water Treatment
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• 제8권3호
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• pp.245-257
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• 2017

The separation of nicotine and tobacco-specific N-nitrosamines is a tough problem in tobacco industry. In this study, separation of nicotine from 4-(methylnitrosamino) -1-(3-pyridyl)-1-butanone (NNK) mixtures was investigated using electrodialysis by taking the principle of the protonation status difference between these two components. The results indicated that the solution pH has a dominant impact on the separation process. In a pH range of 5-7, nicotine molecules are existed as mono- and di-protonated ions and can be separated from the uncharged NNK molecules. The acidic electrolyte is conducive to the separation process from the point of flux and energy consumption; while the alkaline electrolyte has negative impact on the separation process. A current density of $10mA/cm^2$ is an appropriate value for the separation process. The lowest energy consumption of the separation process is 0.58 kWh/kg nicotine with the process cost to be estimated at only $0.208 /kg nicotine. Naturally, electrodialysis is a high-efficiency, cost-effective, and environmentally friendly process to separate and purify nicotine from tobacco juice.

• Membrane and Water Treatment
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• 제7권4호
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• pp.341-353
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• 2016

Papermaking reconstituted tobacco is an important strategy for recycling the waste tobacco residues. To indentify the influences of the inorganic components on harmful components delivery in cigarette smoke, a self-made electrodialysis stack was assembled to desalt the tobacco extract. The influences of the applied current and extract content on the removal rate of the inorganic ions were investigated. Results indicated that the applied current was a dominant impact on the desalination performance. High currents lower than the limiting current density could accelerate the desalting efficiency but cause higher energy consumption. A current of 2 A, or current density of ${\sim}11mA{\cdot}cm^{-2}$, was an optimal choice by considering both the energy consumption and desalting efficiency. A 20% tobacco extract was an appropriate content for the electrodialysis process. More than 90% of inorganic ions could be removed under the optimum condition. The preliminary result indicated that removal of inorganic components was beneficial to decrease the harmful component delivery in cigarette smoke. Naturally, ED is an environmentally friendly and high-effective technology for desalting the tobacco extract.

• Journal of Advanced Marine Engineering and Technology
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• 제19권3호
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• pp.24-32
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• 1995

The scavenging characteristics have a great influence on the performance of a diesel engine, especially slow-speed two-stroke diesel engines which are usually used as a marine propulsion power plant, and they are greatly affected by the conditions in the cylinder, intake and exhaust manifolds, and the opening and closing timing of scavenging ports or exhaust valves during the gas exchange process. Besides, there are many other factors to affect the scavenging characteristics and these factors interact each other very complicatedly. Therefore the simulation program of the gas exchange process is very useful to improve and predict the scavenging characteristics, due to the high costs associated with redesign and testing. In this paper it was attenpted to investigate the effect of the variation of the pressure ratio of intake to exhaust manifolds, and the variation of the opening and closing timing of a exhaust valve by using a computational program for a three-zone scavenging model which was developed by authors. The computed results showed that the scavenging efficiency and delivery ratio increased considerably, but the trapping efficiency decreased with increasing of the pressure ratio of intake to exhaust manifolds. The scavenging efficiency, trapping efficiency, and th conditions of the cylinder gases were affected by the opening timing of the exhaust valve, but the delivery ratio by the closing timing.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1201-1205
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• 2009

Corn starches with different amylose contents were enzymatically modified using Thermus aquaticus 4-$\alpha$-glucanotransferase ($TA{\alpha}GTase$). Upon the enzyme treatment, the chain-length distributions of isoamylolytically debranched products became broader [degree of polymerization (DP): 3-40] than those of untreated corn starches. In addition, a variety of cycloamyloses (CAs) with different sizes were formed by the glucanotransfer activity of $TA{\alpha}GTase$. CAs with DP 5-40 were detectable in all of the $TA{\alpha}GTase$-treated corn starches. From the results of high-performance anion-exchange chromatography and high-performance size-exclusion chromatography analyses, it was suggested that the amount of CAs produced by the enzyme treatment increased as the amylose content of the starches increased. Thus, we concluded that the extent of modification of starch molecules was enhanced in proportion to amylose content by the transfer activity of $TA{\alpha}GTase$. This finding could be useful for developing an efficient process of CA production using this enzyme.