bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of phenol from coupling of talc and peroxidase. Application for depollution of waste water containing phenolic compounds
Authors: Arseguel Didier , Baboulène Michel 
Published: May 2005

AbstractThe degradation of phenol by a combination of horseradish peroxidase/hydrogen peroxide in the presence of talc, a natural abundant and low cost mineral, was investigated. Adsorption of the reaction products on the talc effectively protected the biocatalyst against contamination by oxidative products, thereby prolonging its catalytic action and leading to almost complete elimination of phenols in aqueous media. Suitable conditions for depollution of waste water containing phenolic substances were developed after optimization of various parameters (type and amount of talc, reaction duration).
Transport and hydrolysis of urea in a reactor–separator combining an anion‐exchange membrane and immobilized urease
Authors: Chen Dong‐Hwang , Leu Jen‐Chih , Huang Ting‐Chia 
Published: May 2005

AbstractA membrane reactor–separator, in which an anion‐exchange membrane and a urease‐immobilized poly(vinyl alcohol) (PVA) membrane were clamped together to separate the feed solution and the stripping solution of a dialysis cell, was constructed. The urea in the feed solution passed through the anion‐exchange membrane, water film, and then was hydrolyzed to ammonium carbamate in the urease‐immobilized PVA membrane. The experimental results showed that no ammonium ion was found in the feed solution under either phosphate or citrate buffer systems at 0·05–0·2 mol dm−3 and pH 6–9, and various initial concentrations of urea in the feed solution (20–200 mmol dm−3). This indicates that the water film between two membranes allows the carbamate ions to decompose into ammonium and carbonate ions completely before entering the anion‐exchange membrane. The device therefore can be used for the removal of urea from feed solution, while preventing the backflow of ammonium ions from the stripping solution or water film into feed solution. It has significant potential in the development of a wearable or portable artificial kidney. The properties of the urease‐immobilized PVA membrane were examined. A kinetic model describing the transport‐reaction behavior of urea in the membrane reactor–separator was developed, and the optimum values of the reactor parameters were obtained.
Metal sorption with extractant‐impregnated macroporous resins. 2. Chemical reaction and particle diffusion kinetics
Authors: Juang Ruey‐Shin , Lin Horng‐Chyuan 
Published: May 2005

AbstractThe rates of the sorption of zinc ions from aqueous sulfate solutions with di(2‐ethylhexyl)phosphoric acid‐impregnated Amberlite XAD macroporous resins were measured in finite bath by a batch‐contact time method. The sorption process was initially found to be controlled by a combined chemical reaction and particle diffusion process using a provable modified shrinking‐core model. A more rigorous model based on Fick's law was then developed to elucidate the sorption mechanism, and a procedure was suggested to simultaneously determine the reaction rate constant and effective particle diffusivity.
The influence of temperature on the growth and fatty‐acid composition of Skeletonema costatum in a batch photobioreactor
Authors: Sánchez Sebastián , de la Casa José A. , Martínez Ma Eugenia , Molina Emilio 
Published: May 2005

AbstractThe influence of temperature on the growth and fatty‐acid composition of the microalga Skeletonema costatum (CCAP 1077/b) has been studied. The maximum specific rates of growth (μm) and productivity (PB) were reached between 293 and 298 K. The experimental values of μm–T were adjusted to the function: μ = μ′o · T · exp(‐Ea/RT) − μd · exp(‐Ed/RT). The total content of the saturated acids reached a minimum at 293 K, wheras the maximum amounts of polyunsaturated acids and Σn − 3 HUFA (highly unsaturated n − 3 fatty acids) occurred at 293 and 295·5 K, respectively.
Removal and recovery of mercury from chloride solutions by contact deposition on iron felt
Authors: Grau Javier M. , Bisang José M. 
Published: May 2005

AbstractThis paper deals with the use of iron felt as a reducing agent for the removal of mercury from aqueous dilute solutions containing chloride ions. The kinetic behavior of the mercuric ion reduction was analyzed and its diffusion coefficient was determined with the use of a rotating disk electrode. Experimental results of the removal of mercury from aqueous sodium chloride solutions containing 100 ppm mercury by contact with iron felt are reported. The mercury concentration was decreased to values lower than 0·1 ppm. The recovery of metallic mercury by chemical attack of the residual iron felt was also analyzed.
Sequential anaerobic–aerobic treatment of sulphur rich phenolic leachates
Authors: Kettunen Riitta H. , Rintala Jukka A. 
Published: May 2005

AbstractSequential biological anaerobic–aerobic treatment of oil shale ash dump leachate was studied using laboratory‐scale reactors and bioassays. The COD of the leachate was 2·0–3·0 g dm−3. The leachate was known to contain several phenolic compounds and to have a high sulphur concentration. The proportion of the leachate in the feed of the biological process was gradually increased during a 309 day test period. With 100% leachate in the feed, COD removal was 35% in the anaerobic stage while in the combined process the COD and BOD7 removals were up to 75% and 99%, respectively. The removal of total phenols was insignificant in the anaerobic stage, while up to 85% removal was obtained by the combined anaerobic–aerobic process. In the anaerobic stage, degradation of organic compounds was mainly a result of sulphide production. The results demonstrated that the leachates were amenable to biological treatment.
Targeting the development of membranes for gas separation
Authors: Hinchliffe Anthony B. 
Published: May 2005

AbstractThis paper presents the new concept of ‘Targeting’ the properties of new membrane materials. Cost parameters are defined in terms of effective selectivity and cost permeability. These new parameters, obtained from the analysis of membrane plant suppliers' bids, are used in a procedure which determines the optimal degree of separation and recovery. The use of the targeting methods is illustrated here in the development of new membranes for the separation of CO from an H2/CO syngas for the large‐scale manufacture of acetic acid. The targeting approach can be extended to include other gas separation technologies and will aid the development of a generic methodology for the design of gas separation processes.
Denitrifying kinetics involving the distributed ratio of reductases
Authors: Her Jiunn‐Jye , Huang Ju‐Sheng 
Published: May 2005

AbstractA suspended‐growth batch reactor was used to denitrify synthetic wastewater containing various proportions of nitrate and nitrite. A competitive phenomenon between nitrate‐ and nitrite‐reductase was studied utilizing various proportions of nitrate and nitrite in an anaerobic environment with a temperature of 30°C and methanol as carbon source.By using a non‐linear regression technique, biokinetic constants of the maximum specific reduction rates of nitrate and nitrite (k1, k2) and the Monod half‐saturation coefficients of nitrate and nitrite (Ks1, Ks2) for the proposed two‐step denitrifying kinetics were 1·29 day−1, 0·89 day−1 and 14·3 mg NO‐N dm−3, 10.9 mg NO‐N dm−3, respectively. The result obtained from a series of chemostat studies indicated the Monod‐type kinetic model was more accurate when the distributed ratio of nitrate‐ and nitrite‐reductase in the proposed two‐step denitrifying kinetics was taken into account.
Biosorption of heavy metals (Cd, Cu, Ni, Pb, Zn) by chemically‐reinforced biomass of marine algae
Authors: Leusch Andreas , Holan Zdenek R. , Volesky Bohumil 
Published: May 2005

AbstractParticles of two different sizes (0·105–0·295 mm and 0·84–1.00 mm diameter) of two marine algae, Sargassum fluitans and Ascophyllum nodosum, were crosslinked with formaldehyde (FA), glutaraldehyde (GA) or embedded in polyethylene imine (PEI), followed by glutaraldehyde crosslinking. They were used for equilibrium sorption uptake studies with cadmium, copper, nickel, lead and zinc. The metal uptake by larger particles (0·84–1·00 mm) was higher than that by smaller particles (0·105–0·295 mm). The order of adsorption for S. fluitans biomass particles was Pb > Cd > Cu > Ni > Zn, for A. nodosum copper and cadmium change places. Uptakes of metals range from qmax = 378 mg Pb g−1 for S. fluitans (FA, big particles), to qmax = 89 mg Zn g−1 for S. fluitans (FA, small particles) as the best sorption performance for each metal. Generally, S. fluitans is a better sorbent material for a given metal, size and modification, although there were several exceptions in which metal sorption by A. nodosum was higher. The metal uptake for different chemical modifications showed the order GA > FA > PEI. A comparison of different sorption models revealed that the Langmuir sorption model fitted the experimental data best.
Biodegradation of phenol‐polluted air using an external loop airlift bioreactor
Authors: Ritchie Brian J. , Hill Gordon A. 
Published: May 2005

AbstractBiological air treatment methods are an alternative to conventional treatment methods such as activated carbon adsorption and chemical scrubbing. An external loop airlift bioreactor has been utilized to treat phenol‐contaminated air using Pseudomonas putida. Saturated air was found to be cleansed of phenol below the detectable limit because of the high mass transfer rate of the pollutant from the air and the high growth rate of Pseudomonas putida. The bioreactor was found to degrade over 99% of the inlet phenol at rates from 21·5 to 194 mg h−1 at concentrations between 650 and 850 mg m−3 of air. A model of the system is developed based on an initial transient period followed by a pseudo‐steady state period. The simulations compared well with the experimental data.
Effect of fluid rheological properties on mass transfer in a bioreactor
Authors: Li Guo‐Qing , Qiu Hong‐Wei , Zheng Zhi‐Ming , Cai Zhao‐Ling , Yang Shou‐Zhi 
Published: May 2005

AbstractRheological properties and oxygen mass transfer coefficient (kL a) were investigated in a stirred reactor (10 dm3) in the course of fermentations producing microbial polysaccharides—pullulan and xanthan. The fermentation broths behaved as pseudoplastic non‐Newtonian fluids in both cases. Studies on the relationship between fluid rheological properties and kL a were also carried out. The oxygen mass transfer coefficient decreases during the fermentation and exponential equations have been obtained to describe the relationship between the oxygen mass transfer coefficient, the agitation speed and the apparent viscosity of the broths. Furthermore, comparison of results between pullulan and xanthan fermentations was investigated. For the xanthan fermentation process, mixing and mass transfer in the reactor were more difficult than those for the pullulan fermentation.
Extracellular polymers in activated sludge and stable foams
Authors: Kerley Sarah , Forster Christopher F. 
Published: May 2005

AbstractThe hydrophobicity and surface polymer extracellular polymer characteristics of a range of foams and mixed liquor samples were examined and the species involved studied. The results show that, for samples dominated by Microthrix parvicella, the hydrophobicity of the solids was linearly related to the uronic acid content of the extracellular polymer polysaccharide. The stability of foams was increased significantly with the addition of polyvalent metal ions to the mixed liquors producing the foams.
Enzymatically‐mediated uranium accumulation and uranium recovery using a Citrobacter sp. Immobilised as a biofilm within a plug‐flow reactor
Authors: Macaskie Lynne E. , Empson Ruth M. , Lin Fan , Tolley Mark R. 
Published: May 2005

AbstractBiofilm‐immobilised Citrobacter sp. removed uranyl ion from flows supplemented with glycerol 2‐phosphate. The metal uptake mechanism was mediated by the activity of a cell‐surface bound phosphatase that precipitated liberated inorganic phosphate with uranyl ion as HUO2PO4·4H2O at the bacterial surface. A modified integrated form of the Michaelis–Menten equation is proposed to describe the removal of metal ion by a columnar bioreactor, where the efficiency of metal removal is semi‐quantitatively related to the input flow rate, the total enzyme loading (E0) and the bioreactor activity. With biofilm‐immobilised bacteria, E0 was further divisible (split) into subparameters of phosphatase titre per bacterium and total biomass surface area. Varying the split E0 and the reaction temperature modified the bioreactor performance. The immobilised bacteria retained high metal loads without loss in steady‐state activity. Accumulated metal was recovered as a concentrated solution.
Preparation and characterisation of the perovskite oxide superconductor YBa2Cu3O7 − x
Authors: Dursun G , Winterbottom J M 
Published: May 2005

AbstractA perovskite oxide, YBa2Cu3O7 − x (YBCO), has been prepared by the method of carbonate precipitation from a mixed nitrate solution and oxidised at 950°C in an air atmosphere to obtain a perovskite oxide to be used as a catalyst for H2/CO reactions. The characterisation of the perovskite oxide was performed by using X‐ray diffraction before and after the treatment with different gases, A.C. susceptibility measurements, particle size measurements and temperature programmed reduction (TPR) in which hydrogen was used in order to monitor the changes of the perovskite with temperature in a hydrogen atmosphere. A.C. susceptibility measurements showed that the YBCO perovskite exhibited the typical good superconducting sharp transition temperature at 93 K, indicating that the wet chemical preparation route is suited to the production of this material.
Saccharification of modified starch to maltose in a semi‐continuous counter‐current chromatographic reactor–separator (SCCR–S)
Authors: Shieh M. T. , Barker P. E. 
Published: May 2005

AbstractCombined bioreaction and separation has been successfully carried out in a Simulated Counter‐Current Chromatographic Reactor–Separator (SCCR–S) system for the saccharification of modified starch to maltose and dextrin. The effects of the operating parameters (switch time, eluent flowrate, feed concentration and enzyme activity) on the performance of the SCCR–S system were investigated. By using an eluent of dilute enzyme solution, starch conversions of up to 60% were achieved using lower amounts of enzyme than the theoretical amount required by a conventional bioreactor to produce the same amount of maltose over the same time period. Comparing the SCCR–S system with a continuous rotating annular chromatograph (CRAC) for the saccharification of modified starch showed that the SCCR–S system required only 34·6–47·3% of the amount of enzyme required by the CRAC, system.
Efficient production of ethanol by a fermentation system employing temperature profiling and recycle
Authors: Kobayashi Masahide , Ishida Kohji , Shimizu Kazuyuki 
Published: May 2005

AbstractBased on a mathematical model for ethanol fermentation, the optimal pattern for changing culture temperature to maximize the final ethanol concentration was derived utilizing the maximum principle. The optimal temperature scheme started cultivation at 30°C (upper limit) descending later to 20°C (lower limit). The effects of culture temperature and ethanol concentration on growth and ethanol formation were studied by controlling the ethanol concentration at a specified level using recycle with a hollow fiber module. A novel method of operation was also investigated where temperature was initially kept at 30°C and ethanol concentration was controlled low simultaneously by the recycle system. The culture temperature was eventually lowered and the draw‐off rate through the hollow fiber stopped. This operation was shown to yield significant improvement for efficient ethanol production.
Dehydration of ortho‐boric acid in a three‐phase bubble column reactor operating at low pressure
Authors: Kang Yong , Shim Jung S. , Cho Soo H. , Choi Myung J. , Lee Kyu W. 
Published: May 2005

AbstractThis study investigates the applicability of the bubble column as a reactor to perform the dehydration of ortho‐boric acid efficiently and economically. The effects of operating conditions such as reaction time, temperature, gas flow rate, particle size and solid content in the slurry phase on the fractional conversion of the reaction have been determined, and the performance of the three‐phase bubble column reactor operating at low pressure (92 kPa) has been discussed. It can be noted from this study that the reaction time has been reduced and the particle size and solid content which are required in the slurry phase for favourable fractional conversion have been increased in the bubble column reactor in comparison with those in the continuous stirred tank reactor. The reaction could be described by means of a fluid–solid heterogeneous reaction model.
Preparation and gas separation performance of silicone‐coated polysulfone membranes
Authors: Marchese José , Ochoa Nelio , Pagliero Cecilia 
Published: May 2005

AbstractComposite membranes (CM) were prepared by coating the dense surface of different asymmetric polysulfone flat membranes (AM) with a solution of silicone rubber polymer. The surface porosity (ε) of the dense skin AM samples varied between 4 × 10−5 and 1·5 × 10−8, with an average mean pore size between 0·10 and 0·07 μm. Scanning electron microscopy (SEM), gas permeation experiments (H2, N2, CH4, CO2) and a simple resistance model were used for the determination of structure‐permeability relationships. This study indicates that the CM prepared with polysulfone AM having ε < 3 × 10−7, coated with a concentration of 6% silicone solution and a contact time of 1 min, has the best gas separation performance, with selectivities very close to the intrinsic polysulfone selectivities.
The preparation of activated carbons from chips of oil palm trunk catalysed by ZnCl2/CO2: Surface area and porosity studies
Authors: Hussein Mohd Zobir , Zainal Zulkarnian , Ibrahim Ramli , Kheong Kohr K. , Muhammad Badri 
Published: May 2005

AbstractActivated carbons were prepared by ZnCl2/CO2 activation of the chips of oil trunk. The surface area and the nature of the porosity of the resulting activated carbons were found to be related to the concentration of the impergnated zinc solution to the precursor. It is possible to prepare activated carbons with a fairly high surface area (more than 2000 m2 g−1) from chips of oil palm trunk.
Surface tension as a limiting factor for aerobic n‐alkane biodegradation
Authors: Setti Leonardo , Pifferi Pier Giorgio , Lanzarini Gaetano 
Published: May 2005

AbstractA new mathematical model for n‐alkane biodegradation in crude oil, heavy oil and paraffinic mixtures is described. The pattern of n‐alkane degradation as a function of the inverse of hydrocarbon chain length reported in this paper can be considered as general behaviour for many aerobic n‐alkane biodegradation processes. A new interpretation of n‐alkane biodegradation as a function of surface tension, is given. A mathematical expression was obtained starting from the degradation values of n‐alkane and relative surface tension, which is a parameter independent of fermentation conditions. An interesting parameter, b, was identified which represented the accelerating conversion factor for n‐alkane biodegradation. The findings suggested that the n‐alkane biodegradation. The findings suggested that he n‐alkane biodegradation rate may be affected by the fermentation condition (agitation, aeration, etc.) and by the strain of microorganism, while the behaviour pattern of n‐alkane degradation was essentially linked to the substrate characteristics (molecular structure, molecular weight and density).
Metal ion concentration, time, and pH dependence of metal ion binding to a transferrin metalloprotein affinity chromatography (MAMC) matrix
Authors: Cannell Kevin P. , Vincent John B. 
Published: May 2005

AbstractThe adsorption of transition metal, lanthanide, and actinide ions to avotransferrin (conalbumin) immobilized to sepharose (via the cyanogen bromide method) has been examined. Adsorption of ions as a function of time and adsorption isotherms at pH 8 have been determined and analyzed using the Freundlich model, distribution coefficients between the pH vales 2 and 9 have been measured. The results indicate that immobilization of the protein has little effect on its interactions with metal ions compared with the protein in solution, and important prerequisite for use of this matrix in metalprotein affinity metal homatography (MAMC).
Removal of copper from industrial wastewater by raw charcoal obtained from reeds
Authors: Khalfaoui Brahim , Meniai Abdessalem H. , Borja Rafel 
Published: May 2005

AbstractIn the present paper, we study the adsorption of Cu2+ from industrial wastewater and aqueous solution at 293 K, by a by‐product of activated carbon (raw charcoal) obtained from reds. A Method of preparation of raw charcoal was established and the main adsorption characteristics of metal ions were examined, as well as the static and dynamic conditions of the adsorption process. The adsorbent properties of the charcoal used were also studied. The presence of other metal ions in the solution decreases the adsorption capacity for copper, and the chemical nature of the charcoal surface and metal ions have a great significance for the adsorption process. The area of charcoal was about 400 m2 g−1 at a carbonization temperature of 973 K.
Electrosynthesis of β‐methylpentadecanedioic acid dimethyl ester
Authors: Zhongcheng Zhang , Jiali Liu , Yuxia Shang 
Published: May 2005

Abstractβ‐Methylpentadecanedioic acid dimethyl ester (I) was synthesized electrochemically by Kolbe reaction using β‐methylglutaric acid monomethyl ester (II) and α,ω‐dodecanedioic acid monomethyl ester (III) as starting materials in MeOH solution. Electrolysis was carried out ofr about 4–5 h, when solution pH ≥ 7, followed by extraction with petroleum ether and distillation to obtain a colourless oily product (I) The minimum production cost occurred when the mole ration of II to III was 1:1·38 and unreacted III could be recovered. The product synthesized (I) completely met the requirement of artificially synthesized musk.
Catalytic wet oxidations of phenol‐ and p‐chlorophenol‐contaminated waters
Authors: Chang Chiehmign J. , Li Shiow‐Shya , Ko Ching‐Ming 
Published: May 2005

AbstractThe rate constant and activation energy of liquid‐phase oxidation catalyzed by CuSO4 · 5h2O, and Co2O3, were found for synthesized wastewaters containing 1000 mg dm−3 phenol and 1500 dm−3 p‐chlorophenol, respectively. Among the catalysts, CuSO4 · 5H2O was demonstrated to be the most effective in reducing the concentration of phenols in wastewaters. The effects of oxygen flow rates and temperatures on the oxidation efficiency were also discussed. The analysis of total organic carbon on the end products after oxidations showed that the liquid phase contained only 10% of intermediate products. Oxidation at different pH values suggested that phenols could be favourably destroyed in an alkaline medium.
Use of a genetic algorithm in the development of a synthetic growth medium for Arthrobacter simplex with high hydrocortisone Δ1‐dehydrogenase activity
Authors: Weuster‐Botz D. , Pramatarova V. , Spassov G. , Wandrey C. 
Published: May 2005

AbstractThe production process for Arthrobacter simplex high specific hydrocortisone Δ1‐dehydrogenase activity and biomass yield (full experimental plan: 1·5 × 1014 experiments). The specific hydrocortisone Δ1‐dehydrogenase activity was improved by a vector of 4·5 to 1800 U g−1. With the optimized medium composition in a stirred tank reactor for batch production of A. simplex, a specific hydrocortisone Δ1‐dehydrogenase activity of 2000–3000 U g−1 dry biomass was achieved depending on harvest time (previously reported data: 18–37 U g−1).