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Semi-batch Reactor (semi-batch + reactor)
Selected AbstractsDecolorization of RR-120 Dye Using Ozone and Ozone/UV in a Semi-Batch ReactorTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2004Mohammad Kazemi Abstract Treatability of RR-120 aqueous dye solutions using O3 and O3/UV was studied in a bench scale set-up. Reduction in colour and chemical oxygen demand (COD) under various pH and initial dye concentrations were investigated. Pseudo first order reaction rate was satisfactorily used for kinetic interpretations in destruction of the dye. The results showed that decolorization with O3 was faster at neutral pH values. While use of UV had a small effect on ozonation at low pH values, UV radiation had a considerable effect at pH values of 7 and above. It was found that ozone utilization efficiency of higher than 95% could be attained in the experimental set up. On a étudié la possibilité de traitement de solutions aqueuses de colorant RR-120 à l'aide d'O3 et O3/UV dans un banc d'essai. La réduction de la demande chimique en oxygène (DCO) et en colorant a été étudiée pour différentes concentrations initiales de colorant. La vitesse de réaction du pseudo-premier ordre a été utilisée avec succès pour les interprétations cinétiques de la destruction du colorant. Les résultats montrent que la décoloration avec l'O3 est plus rapide à des valeurs de pH neutres. Alors que le recours aux UV a un faible effet sur l'ozonation à de faibles valeurs de pH, la radiation par UV a un effet considérable à des valeurs de pH de 7 et au-dessus. On a trouvé qu'une efficacité d'utilisation de l'ozone supérieure à 95% pouvait être atteinte dans l'installation expérimentale. [source] Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristicsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2009Jen-Mao Fanchiang Abstract BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi-batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5-day biochemical oxygen demand (BOD5) concentration, BOD5/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD5 concentration generally appeared after ozonation. Also, the BOD5/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright © 2009 Society of Chemical Industry [source] Disinfection of recycled red-meat-processing wastewater by ozoneJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2005Jiangning Wu Abstract Ozonation of a real red-meat-processing wastewater was conducted in a semi-batch reactor to explore the possibility of the water reuse. The experimental results revealed that ozone was very effective in disinfection of the red-meat-processing wastewater. After 8 min of ozonation with an applied ozone dose of 23.09 mg min,1 liter,1 of wastewater, 99% of aerobic bacteria, total coliforms and Escherichiacoli were inactivated. Empirical models were developed to predict the microbial inactivation efficacy of ozone from the CT values for the real red-meat-processing wastewater. A correlation was also derived to estimate the CT values from the applied ozone dose and the ozone contact time. The results also revealed that under the ozonation condition for 99% inactivation of aerobic bacteria, total coliforms and E coli, the decrease in the chemical oxygen demand and the 5-day biological oxygen demand of the wastewater were 10.7% and 23.6%, respectively. However, ozonation under this condition neither improved the light transmission nor reduced the total suspended solids (TSS) despite of the decolorization of the wastewater after ozonation. Copyright © 2005 Society of Chemical Industry [source] Advanced oxidation processes for destruction of cyanide from thermoelectric power station waste watersJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2004José M Monteagudo Abstract Several advanced oxidation processes for the destruction of cyanide contained in waste waters from thermoelectric power stations of combined-cycle were studied. Thus, oxidation processes involving ozonation at basic pH, ozone/hydrogen peroxide, ozone/ultraviolet radiation and ozone/hydrogen peroxide/ultraviolet radiation have been carried out in a semi-batch reactor. All these methods showed that total cyanide can be successfully degraded but with different reaction rates, and the decrease in the total cyanide concentration can be described by pseudo-first order kinetics. The influence of pH and initial concentration of hydrogen peroxide was studied to find the optimal conditions of the oxidation process. Experimental results of the single ozone treatment indicated that total cyanide is destroyed more rapidly at higher pH (12), while ozonation combined with H2O2 and/or UV is faster at pH 9.5. The optimum concentration of H2O2 was 20.58 × 10,2M because an excess of peroxide decreases the reaction rate, acting as a radical scavenger. The total cyanide degradation rate in the O3/H2O2(20.58 × 10,2M) treatment was the highest among all the combinations studied. However, COD reduction, in the processes using UV radiation such as O3/UV or O3/H2O2/UV was about 75%, while in the processes with H2O2 and/or O3/H2O2 was lower than 57% and was insignificant, when using ozone alone. Copyright © 2003 Society of Chemical Industry [source] Branching and Crosslinking in Coordination TerpolymerizationsMACROMOLECULAR REACTION ENGINEERING, Issue 4 2007Rolando C. S. Dias Abstract A general kinetic method, based upon population balances of generating functions, is applied to the prediction of the microstructure and molecular size of non-linear terpolymers obtained through the coordination polymerization of two monovinyl monomers and a non-conjugated diene. A rather complex kinetic scheme involving crosslinking and long-chain branching is considered. It is shown that even in these conditions it is possible to carry out the prediction of molecular size and mass distributions, sequence size distributions, and z -average mean-square radius of gyration of the polymers. The influence of some kinetic parameters on the properties of the products is studied, considering a homogeneous operation in a semi-batch reactor. The used simulation method is able to predict these properties before and after gelation whenever it occurs. [source] In-situ catalytic synthesis of ammonia from urea in a semi-batch reactor for safe utilization in thermal power plantASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010J. N. Sahu Abstract Urea as the source of ammonia for the flue gas conditioning/NOx reduction system in thermal power plant has the obvious advantages that no ammonia shipping, handling and storage is required. The process of this invention minimizes the risks and hazards associated with the transport, storage and use of anhydrous and aqueous ammonia, as ammonia is a highly volatile noxious material. But no such rapid urea conversion process is available as per requirement of high conversion in shorter time, so here we study the catalytic hydrolysis of urea for fast conversion in a semi-batch reactor. The catalysts used in this study are: TiO2, fly ash, mixture of Ni and Fe and Al2O3. Number of experiments was carried out in a semi-batch reactor at different catalyst doses, temperatures and concentration of urea solution from 10 to 30% by weight and equilibrium study has been made. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||