bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery of Metal Ions by Microfungal Filters
Authors: Wales David S. , Sagar Brian F.
Published: July 2010

Many microfungi contain chitin/chitosan as an integral part of the cell wall structure. The binding of toxic and heavy metal ions by chitosan or partly deacetylated chitin is a direct consequence of the base strength of the primary amine group and is most effective for those metals that form complexes with ammonia. Of the microfungi studied, hyphae from Mucor mucedo and Rhizomucor miehei, after treatment with hydroxide to expose the chitin/chitosan, were found to be most effective in the capture of metal ions. Chemically treated mycelia have so far been shown to bind silver, zinc, lead, copper, nickel, cobalt, cadmium, iron and chromium, with the efficiency of metal‐ion binding apparently being inversely proportional to the valency state of the metal ions to be bound.

Wet‐laid papers produced from mixed slurries of treated mycelia and various conventional paper‐making and textile fibres have exceptionally good tensile‐ and bursting‐strength properties, particularly in the wet state. Papers containing 1 g treated mycelia removed up to 90% of various metal ions in solution (50 cm3, 7–5 mmol dm−3) with flow rates of 0.5 cm3 cm−2 min−1. However, the total metal‐ion binding capacities of single‐thickness microfungal papers are limited under constant flow conditions. The total volume flowing through the system before metal‐ion breakthrough occurs increases in direct proportion to the number of sheets of microfungal paper but the concomitant reduction in flow rates becomes a limiting factor. Mycelia‐containing structures that allow efficient metal‐ion binding at commercially acceptable flow rates are currently being investigated.
Review of biotechnology applications to nuclear waste treatment
Authors: Ashley Nicholas V. , Roach Daniel J. W.
Published: July 2010

This paper gives an overview of the feasibility of the application of biotechnology to nuclear waste treatment. The contents are based on a report which PA Technology carried out for the Department of the Environment (DoE Reference: DoE/RW/88.008 Sector No 2.3).

Many living and dead organisms accumulate heavy metals and radionuclides. The controlled use of this phenomenon forms the basis for the application of biotechnology to the removal of radionuclides from nuclear waste streams. Indeed, biotechnology offers a series of new opportunities for removal of radionuclides from dilute aqueous process effluents. Such technology is already used for heavy metal removal on a commercial basis and could be optimised for radionuclide removal.

An overview of biotechnology areas, namely the use of biopolymers and biosorption using biomass applicable to the removal of radionuclides from industrial nuclear effluents is given. The potential of biomagnetic separation technology, genetic engineering and monoclonal antibody technology is also to be examined. The most appropriate technologies to develop for radionuclide removal in the short term appear to be those based on biosorption of radionuclides by biomass and the use of modified and unmodified biopolymers in the medium term.
Metal recovery using chitosan
Authors: Onsosyen Edvar , Skaugrud Osyvind
Published: July 2010

Chitosan is a natural polycationic polymer which possesses valuable properties as a metal recovering and water purifying agent. Applications are

—waste water treatment for heavy metal and radio isotope removal and valuable metal recovery,

—potable water purification for reduction of unwanted metals,

—agriculture—controlled release of trace metals essential to plant growth,

—food—complex binding of iron in precooked food to reduce ‘warmed‐over flavour’.

The interactions of metals with chitosan are complex, probably simultaneously dominated by adsorption, ion‐exchange and chelation. To study this it is of utmost importance to work with well characterized chitosans. This has been a problem as available characterizing methodology is limited.

Degree of polymerization and deacetylation and the distribution of acetyl groups along the polymer chain is of crucial importance for chitosan metal interacting characteristics. Making chemical derivatives is a way to alter the metal interacting characteristics of chitosan.

Chitosan possesses general coagulant/flocculant characteristics towards bio‐molecules and surfaces.
Contribution of endo‐ and exocellular glucose oxidase to gluconic acid production at increased dissolved oxygen concentrations
Authors: Traeger M. , Qazi G. N. , Onken U. , Chopra C. L.
Published: July 2010

For gluconic acid fermentation with Aspergillus niger oxygen‐enriched air was used to increase dissolved oxygen concentration during the production phase from c. 30% to 100% saturation related to air at 1 bar. At the highest dissolved oxygen concentration the activity of glucose oxidase increased more than three‐fold. At the same time, the gluconic acid production rate increased by a factor of two. During the fermentations, glucose oxidase was present endocellularly as well as exocellularly; the presence of this enzyme in the broth was due to a controlled secretion. It was found that the two fractions of the enzyme showed different activities in their contribution to overall acid production. Due to a limitation of oxygen diffusion into the mycelial pellets, activity of endocellular enzyme was reduced by 50–80%. However, since the major part of the enzyme was present in the pellets the action of endocellular glucose oxidase is not negligible. This latter factor must be taken into consideration when optimizing bioreactor design.
Conversion of methanol on silicoaluminophosphate—formation of hexamethylbenzene and olefins
Authors: Das Jagannath , Bhattacharya Anjana , Goswami Tarun K. , Roy Sisir K.
Published: July 2010

The catalytic conversion of methanol over new generation molecular sieve silicoaluminophosphate of type 5 (SAPO‐5) has been studied. The formation of gaseous, liquid and solid hydrocarbons have been observed. While the gaseous hydrocarbon contains 32·5–56·7 wt% of olefins, the liquid product comprises hydrocarbons in the boiling range 98°C‐320°C as determined by gas chromatographic distillation technique. The solid hydrocarbon was identified as hexamethylbenzene by physical, chemical and spectral analysis.
Optimal feed temperature for an immobilized enzyme packed‐bed reactor
Authors: Lin Sheng H.
Published: July 2010

Optimal feed temperature was determined for a nonisothermal immobilized enzymatic reaction with enzyme deactivation in a packed‐bed reactor. The optimal feed temperature was obtained by maximizing the average substrate conversion over a given reaction period. Simulation showed the optimal feed temperature to be strongly dependent on the flow dispersion, the reaction activation energy, the corresponding enzyme inactivation energy and the heat of reaction. It was also observed that in a plug flow reactor the enzyme reaction generally exhibited a lower optimal feed temperature and higher substrate conversion than in a continuously stirred tank reactor.
One‐step oxidation of cyclohexane to adipic acid
Authors: Kulsrestha Girendra N. , Shankar Uma , Sharma Jaipal S. , Singh Jasvinder
Published: July 2010

Liquid‐phase oxidation of cyclohexane with Co(III) catalyst and gaseous oxygen was found to be influenced by reaction temperature, catalyst concentration and the duration. Maximum adipic acid product selectivity (77%) with about 85% cyclohexane conversion was attained at 100°C using catalyst: cyclohexane molar ratio 0·08. Under these conditions more than 80% cyclohexane was converted in the first hour, although selectivity to adipic acid continued to increase for the next 5 h. Cyclohexyl acetate and cyclohexyl monoadipate were identified as important intermediates. This study supports the mechanism proposed by Schultz, J. G. D. and Opchenko, A., J. Org. Chem., 38 (21) (1973) 3729.
Preparation of battery‐grade manganese dioxide through disproportionation of partially oxidised hydrous manganese oxide in dilute sulphuric acid
Authors: Kanungo S. B.
Published: July 2010

Manganese hydroxide was precipitated from MnSO4 and NH4OH at controlled pH, partially oxidised by aeration and finally calcined at 573–623 K to yield manganese oxide with oxidation state between +3 and +4. When the calcined oxide was leached in dilute sulphuric acid, MnO2 of high electrochemical activity was obtained. In order to improve the bulk or packing density of the product various oxidants were added during the aerial oxidation of the Mn(OH)2 slurry and also during the leaching in dilute H2SO4. It was observed that the best results were obtained when active MnO2 was added during the aerial oxidation of Mn(OH)2 slurry.
The production of propionic acid from sugars by fermentation through lactic acid as an intermediate
Authors: Tyree Ralph W. , Clausen Edgar C. , Gaddy James L.
Published: July 2010

As an alternative to propionic acid production from sugars by species of propionibacteria, propionic acid may be produced from sugars through lactate as an intermediate. Propionibacteria are actually able to utilize lactate as a substrate much more rapidly than glucose. In this study, Lactobacillus xylosus and Propionibacterium shermanii were utilized to convert glucose and xylose to propionate through lactate as an intermediate. Pure culture batch studies were carried out to obtain fermentation parameters for the two cultures. The pure cultures were then combined in a mixed culture series arrangement designed to prevent nutrient limitation. Finally, propionic acid production from lactate was demonstrated in a cross‐linked immobilized cell reactor using lactate added to the medium and produced by L. xylosus in a continuous stirred tank reactor. Productivities of 14 g dm−3 h−1 at a 9 min residence time (2·1 g dm−3 propionate) and 2 g dm−3 h−1 at a 9·9 h residence time (19·7 g dm−3 propionate) were obtained without pH control.
A high containment polymodal pilot‐plant fermenter—design concepts
Authors: Hambleton Peter , Griffiths J. Bryan , Cameron D. Ross , Melling Jack
Published: July 2010

A 225 dm3 pilot‐plant bioreactor system has been designed and constructed that is suitable for biohazardous fermentations. The design enables operation at containment levels above the requirements of good industrial large‐scale practice (GILSP) without secondary containment of the whole plant. The main biosafety features of the systems include the use of steam barriers on O‐ring seals, supply lines and stirrer seals, multiple O‐ring seals, piping of condensate lines and pressure relief systems to a ‘kill tank’, double filtration of inlet and off gases and a mobile isolation unit that allows localised containment of sample valve and probe entry ports. The fermenter can, with minor modifications, be operated as a bottom‐ or top‐stirred reactor for the culture of microbial or animal cells, or as an airlift reactor. The design offers considerable flexibility that could prove cost‐effective for process development and production.

The relevance of the various design features to enable bioreactor operations at pilot‐plant scale to be carried out in compliance with current guidelines for large‐scale culture of recombinant microorganisms and microbial pathogens is discussed.
Inhibition of trypsin by t‐Butyloxycarbonyl‐α‐aza‐(4‐aminophenyl)alanine phenyl ester
Authors: Din H. , Gray C. J. , Ireson J. C. , McDonald R.
Published: July 2010

T‐Butyloxycarbonyl‐α‐aza‐(4‐aminophenyl)alanine phenyl ester (Fig. 1, III: R = NH2) has been synthesized. The rate of inhibition of trypsin (EC 3.4.21.4) by this compound (due to acylation followed by slower deacylation) shows a marked pH maximum at approximately 6. The shape of the pH—rate curve is discussed in terms of (i) the normal pH—activity curve of trypsin reacting with a charged substrate, i.e. the protonated form of the amino compound, (ii) the deprotonation of the 4‐amino group with pKa 4·3, and (iii) the lower rate of reaction of the enzyme with the uncharged, deprotonated form of the ester.
Dry anaerobic batch digestion of the organic fraction of municipal solid waste
Authors: Brummeler E. Ten , Horbach H. C. J. M. , Koster I. W.
Published: July 2010

Anaerobic digestion at high solid concentrations (dry anaerobic digestion) is an attractive method for the stabilization of solid organic wastes. A new concept for dry anaerobic batch digestion (BIOCEL) of the organic fraction of municipal solid waste is presented. The start up of a BIOCEL reactor was studied with several methods of process set up and operation. Dry anaerobic digestion of the pure undiluted organic fraction obtained from a shredding/separation process was not accelerated by partial spatial separation of substrate and methanogenic inoculum (granular sludge) or leachate recycle, or both. With these three methods after 30 days the high organic acids concentration and low pH in the reactor indicated a sour reactor, unable to establish significant methane production.

When the organic fraction was digested in combination with compost addition (40% (w/w) of the initial solids) and leachate recycle, the stabilization rate increased significantly. Leachate recycling in combination with partial spatial separation of the substrate/compost mixture and the inoculum showed the shortest lag phase in the methane production and the shortest digestion time. When the digested residue of a completed digestion was applied as the methanogenic inoculum (40% (w/w) of the initial total solids) the digestion time was slightly shorter. It is concluded that dilution with compost had a positive effect on the start up of the dry anaerobic digestion and compensated for a suboptimal amount of initial methanogenic biomass. During the start up of dry anaerobic batch digestion of municipal solid waste the rapid recovery of methane formation from an initial overloading was observed and was found to be the result of a population shift in the methanogenic biomass and the existence of zones in the reactor with more optimal conditions (higher p H, lower organic acids concentration). The observed digestion time was 36 days. Recommendations are given to shorten the period needed, for complete digestion.
Hydroconversion of n‐heptane on platinum/H‐Mordenite catalysts prepared via different routes
Authors: Aboul‐Gheit Ahmed K. , Menoufy Mohammed F. , El‐Morsi Akila K.
Published: July 2010

Two Pt/H‐mordenite catalysts were prepared via different routes: (a) by impregnating H2PtCl6 in H‐mordenite (HM) (catalyst 1) and (b) in NH4HM (catalyst II), followed by drying, calcination and reduction. Catalyst I was found (i) to be more active for n‐heptane hydroconversion, (ii) to be more selective for its isomerisation, (iii) to encounter more diffusion limitation as it yields a larger Thiele modulus, (iv) to give a lower effectiveness factor and (v) to give lower activation energy, Ea, values than catalyst II. A study of the pressure effect between 1·5 and 5·5 MNm−2 showed an increase of the catalytic activities to a maximum at 3·0 MNm−2, followed by a decrease. A compensation effect plot gave a linear relationship between In A (pre‐exponential factor in the Arrhenius equation) and Ea at various pressures for n‐heptane hydroconversion and its hydrocracking. High selectivities for central hydrocracking of heptane components and high iso‐butane to n‐butane ratios were obtained on both catalysts.
Comparative cost of colour removal from textile effluents using natural adsorbents
Authors: Nassar Mamdouh M. , El‐Geundi Mohammad S.
Published: July 2010

A number of low‐cost materials (natural clay, bagasse pith and maize cob) have been used as adsorbents for dyestuffs (Astrazon Blue, Maxilon Red and Telon Blue) in aqueous solutions. The adsorption capacity for each dye‐adsorbent system has been determined. The relative costs of dye removal were reported based on adsorption capacity only. The following results were found. First, the relative cost of the removal of Astrazon Blue using natural clay, bagasse pith and maize cob was found to be only 1·7%, 3·9% and 4·1% that of carbon respectively. Second, the relative cost of the removal of Maxilon Red using natural clay, maize cob and bagasse pith was found to be only 2·4%, 8·3% and 10·3% that of carbon respectively. Last, the relative cost of the removal of Telon Blue using maize cob, natural clay and bagasse pith was found to be only 2·9%, 3·0% and 5·2% that of carbon respectively.
A low cost adsorbent from spent bleaching earth. I—the selection of an activation procedure
Authors: Pollard Simon J. T. , Sollars Christopher J. , Perry Roger
Published: July 2010

The conversion of a spent filter cake from the edible oil industry to a heterogeneous clay‐carbon adsorbent is reported. Chemical and physical activation procedures have been applied and the resulting materials screened by carbon content and aqueous phenol uptake. Full adsorption isotherms are plotted for sorbents with high phenol capacities and their adsorptive behaviour is modelled to the Freundlich and Langmuir isotherms.
Fluorescent whitening agents in heavy duty liquid detergents
Authors: Lee Frank
Published: July 2010

Fluorescent whitening agents (FWAs) for laundry detergents have been known and successfully used for decades to provide a valuable contribution to the washing results. The increased sophistication of detergent formulations, which is expected to continue into the 1990s, presents new needs and challenges for the FWA.

This paper looks specifically at the development of the heavy duty liquid detergent segment and its influence on FWA formulation and performance characteristics such as processability, compatibility, stability and spotting.
Effective laundry products leading to lower chemical usage
Authors: Hepworth Paul
Published: July 2010

Laundry washing consumes and releases into the sewage treatment system large amounts of chemicals such as phosphate builders, surfactants and alkalis. By presenting the builders and surfactants in a more instantly usable form, considerable reductions in total chemical requirements can be achieved. Nonaqueous laundry liquids described here offer a 50 to 130% reduction in chemicals entering the sewage treatment system.
Prediction of the fate of detergent chemicals during sewage treatment
Authors: Birch Ronald R.
Published: July 2010

Consideration of a conventional growth model for the activated sludge sewage treatment process has resulted in the development of an improved method for assessing the biodegradability of chemicals. The model indicates the importance of sludge retention time (SRT) and temperature on the treatment efficiency and suggests a need to control and examine the effect of both parameters on the biodegradation of materials.

The effect of SRT and temperature is illustrated by data for the nutrification of ammonia and the biodegradation of alcohol‐ and alkylphenol‐ethoxylates, LAS and nitrilotriacetic acid. The results illustrate the predictive power of the technique in obtaining results in the laboratory which are consistent with data reported from studies involving full scale treatment plants.
Reactions of oxygen and toluene in an electrical discharge reactor
Authors: Eriksson Karl R. , Brooks Brian W. , Glover John
Published: July 2010

Gaseous mixtures of oxygen and toluene have been passed through a 50 Hz electrical discharge reactor at low pressure. Oxidation reactions produced benzaldehyde, benzene, benzyl alcohol and cresols. Reaction rates varied with partial pressure of reactants, electrical field strength and temperature, although, in the absence of an electrical discharge the thermal reaction was negligible. A fit to experimental data was obtained with an equation which included reactant concentrations, temperature and applied voltage.
Study on the kinetics of hazardous pollutants adsorption and desorption by biomass: Mechanistic considerations
Authors: Tsezos Marios , Wang X.
Published: July 2010

The kinetics of biosorption and desorption of lindane, diazinon and 2‐chlorobiphenyl by inactive activated sludge and Rhizopus arrhizus biomass was studied. The effects of solution initial concentration, temperature and type of biomass on the observed biosorption and desorption rates were also examined. The results of the present work show that the biosorption rates are reasonably rapid, with equilibrium attained within 4 h by activated sludge and 1 h by R. arrhizus. The observed biosorption kinetics consist of a rapid initial stage followed by a slower second stage. The observed rate of organic pollutants biosorption by activated sludge during the first stage can be described by second order kinetics. The biosorption of lindane by both biomass types is reversible and the desorption process is rapid and could be described by zero order kinetics when activated sludge is used as adsorbent. The type of biomass can have a significant effect on the observed biosorption and desorption rates.
Isolation of σ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine from culture broths by covalent chromatography
Authors: Orford Colin D. , Adlard Maxwell W. , Perry David
Published: July 2010

An efficient procedure for the isolation of reduced ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine (ACV) from culture supernatants of β‐lactam antibiotic‐producing microorganisms is described. The method utilises covalent chromatography to isolate thiols from culture broths that have been deproteinised and undergone borohydride reduction. 2‐Pyridyl disulphide activated thiopropyl Sepharose was employed batchwise to isolate the thiols present in such broths from cultures of the known ACV excreter Cephalosporium acremonium N2 and the penicillin producer Penicillium chrysogenum P2. ACV was separated from these mixtures of thiols by gel permeation chromatograhy. Reversed‐phase HPLC analysis showed the ACV to be of a high purity unless isolated from a highly complex culture medium.
A methanol fuel cell having a molybdenum‐modified platinum—SPE membrane electrode
Authors: Nakajima Hiroshi
Published: July 2010

A direct methanol fuel cell was constructed by employing a platinum—solid polymer electrolyte composite (Pt—SPE). It was confirmed, by using the cell, that adsorption of molybdenum species on Pt enhances catalytic activity for methanol oxidation both at Pt and Pt—SPE electrodes. The molybdenum treatment increased the cell voltage by 100–200 mV at a current density lower than 2 mA per apparent unit area. Methanol permeated through the SPE membrane and reduced stability of the fuel cell.
Immobilization of Desulfovibrio vulgaris cells with hydrogenase activity
Authors: Barreto M. C. , Cabral J. M. S.
Published: July 2010

Desulfovibrio vulgaris intact cells immobilized in calcium alginate retained 45% of the hydrogenase activity of free cells. Cell immobilization had no effect on the optimum temperature for the hydrogen uptake rate, whereas the pH optimum was shifted to a higher value. The immobilization conferred on the cells a protection both against oxygen inhibition and thermal denaturation of the hydrogenase system.
Whither Zinc?
Authors: Hopkin W.
Published: July 2010

Present technology for production of primary zinc by the Imperial Smelting and electrolytic zinc processes followed long and expensive process development, driven by the need to improve on inefficient, small scale and labour intensive retorting processes. These newer processes are complementary, very efficient and continue to develop to meet evolving needs, with no sign of a shortage of suitable concentrates to force major change to newer technology.

Several proposed intensive zinc processes to treat calcines, and an innovative direct process treating polymetallic sulphide concentrates, all need to condense bulk metallic zinc from a dust‐ or fume‐laden gas, e.g. by absorption in a lead or zinc condenser. Efficient metal recovery and process control will meet major engineering and operating difficulties. Successful commercialisation to bulk zinc, if ever achieved, will require long and expensive development, and present need does not justify the costs and effort involved.

Whither zinc? Most likely down an evolutionary path from present technology, with added environmental protection whose costs must be carried by the industry, then by society.
The use of lipase (acetone powder) from Vernonia galamensis in the fatty acid analysis of seed oils
Authors: Afolabi Oladapo A. , Ologunde M. O. , Anderson Winston A. , Read John S. , Dacosta Michelle D. , Epps Flavia A. , Ayorinde Folahan O.
Published: July 2010

Examined in this study is a potential application of Vernonia galamensis lipase (acetone powder) in enzyme‐catalyzed hydrolysis of seed oils, most especially of those containing reactive functionalities which are easily affected under drastic hydrolytic and methylating/transesterification conditions during fatty acid analysis.

Eight seed oils from V. galamensis, Ximenia kaffra, castor, corn, soyabean, palm kernel, sunflower and olive were hydrolyzed by lipase (acetone powder) followed by methylation using diazomethane in ethyl ether. Results obtained showed that the lipolytic hydrolysis of triglycerides by V. galamensis lipase (acetone powder) was probably nonspecific and did not result in isomerization and as such hydrolyzed the triglycerides of the seed oil in a fashion that the resulting fatty acids were unaltered during hydrolysis. The fatty acids obtained were representative of the parent seed oils. Values reported for the various seed oils were similar to those of previous studies.
Sorption of cadmium and lead ions on modified groundnut (Arachis hypogea) husks
Authors: Okieimen Felix E. , Okundia Esther U. , Ogbeifun David E.
Published: July 2010

The removal of cadmium and lead ions from aqueous solutions by groundnut husks modified by reaction with EDTA (% N = 12.05) was examined by equilibrium sorption studies at 29°C. The maximum metal ion binding capacity of the EDTA‐modified husk determined from the sorption isotherm from solutions of pH 6.8 was found to be 0.36 mmol g−1 and 0.19 mmol g−1 for Cd(II) and Pb(II) ions, respectively. It was found that the rate of sorption was particle‐diffusion controlled, and the particle‐diffusion control rate coefficient was determined to be of the order of 10−2 min−1.
Characterization of cellulase and xylanase activities of Clostridium celerecrescens
Authors: Palop M. Llanos , Vallés Salvador , Piñaga Francisco , Flors Agustí
Published: July 2010

The production of cellulases and xylanase by Clostridium celerecrescens, a new anaerobic mesophilic cellulolytic bacterium, was studied using various substrates (cellobiose, xylan and cellulose Whatman CF‐11). While both cellulase (β‐1,4‐D‐glucan glucanohydrolase) and xylanase (β‐1,4‐xylan xylanohydrolase) were produced on cellulose, only the latter was produced when xylan was used as the sole carbon source. A weak p‐nitrophenyl‐β‐D cellobiohydrolase activity was detected in the extracellular filtrates when using cellulose as a substrate. Otherwise, β‐glucosidase (p‐nitrophenyl‐β‐D‐glucopyranosidase) was always found to be associated with the bacteria and reached its maximum levels of growth on cellobiose. In all cases, enzyme production showed a cell growth associated profile. Activities of these enzymes had their optimal values within the ranges of temperature and pH reported for the corresponding enzymes from similar anaerobic mesophilic microorganisms, although a relatively high optimum temperature, 55°C, was found for xylanase. All enzymes showed a 90% reduction of half‐life time for each 8°C increment of temperature. A 50% inhibition of xylanase and β‐cellobiohydrolase activity was observed, through a competitive mechanism, by xylose (0.677 mmol dm−3) and cellobiose (28 mmol dm−3) respectively.
Hydrogenation of phenol to cyclohexanone over Pd/MgO
Authors: Galvagno S. , Donato A. , Neri G. , Pietropaolo R.
Published: July 2010

Hydrogenation of phenol to cyclohexanone has been investigated in the temperature range 160–250°C on a series of Pd/MgO catalysts. At 160°C the orders of reaction were found on all catalysts to be about −1 with respect to phenol and about + 1 with respect to hydrogen. On the basis of the kinetic results it is suggested that the rate determining step is the surface reaction between phenol and hydrogen adsorbed on the catalyst. An increase in the reaction temperature decreases the rate of reaction. This has been explained through a change of the orders of reaction which increase with temperature. Palladium dispersion does not influence the reaction mechanism. The specific activity was found to be independent of palladium particle size.
Polarographic reduction mechanism and quantum chemical calculations of some α‐arylhydrazononitriles
Authors: Ismail M. I.
Published: July 2010

The polarographic reduction of 2‐arylhydrazono‐3‐keto‐3‐phenylpropionitriles (Ia–i) and 2‐arylhydrazono‐3‐ketobutyronitriles (IIa–i) over a wide pH range is reported and discussed. The mechanism of the electrode process is elucidated and confirmed via coulometric analysis, quantum chemical calculations and IR spectra of the electrolysis products. The molecular structures and molecular orbital energies were calculated and correlated with the redox potentials of these compounds.
1‐Amino‐4‐hydroxyanthraquinone‐β‐ethers and thioethers: Red dyes for synthetic‐polymer fibres
Authors: Peters Arnold T.
Published: July 2010

Condensation of 1‐amino‐2‐bromo‐4‐hydroxyanthraquinone and of 1‐amino‐3‐bromo‐4‐hydroxyanthraquinone with alcohols, phenols and thiols yields the corresponding β‐ethers and thioethers. These compounds colour polyester in deep rose‐red to violet‐red hues of excellent build‐up and good fastness to light and sublimation. The colour of the dyes is discussed with respect to the nature and orientation of the β‐substituents.
Solubilities and diffusivities of N2O and CO2 in aqueous sulfolane solutions
Authors: Wang Yi‐Wei , Otto Frederick D. , Mather Alan E. , Xu Shuo
Published: July 2010

The solubilities of N2O and CO2 in aqueous sulfolane solutions and pure sulfolane solvent, and the diffusivities of N2O in aqueous sulfolane solutions were measured and correlated over the temperature range from 20° to 85°C; also, the data for density and viscosity that were needed in this experimental work were measured. This experiment revealed that the parameter of N2O analogy method depends not only on the temperature, but also on the character of the solvent. Therefore, different solvents possess different analogy parameters. Only for dilute aqueous solutions can the parameter be replaced by the analogy parameter of water. The results also proved that the sum of volume fractions contribution is a simple method to estimate the solubility in aqueous sulfolane solutions over the whole range of the concentrations and experimental temperatures, with an average deviation of less than 4·0%.
Starch hydrolysis kinetics of Bacillus licheniformis α‐amylase
Authors: Komolprasert Vanee , Ofoli Robert Y.
Published: July 2010

The reaction kinetics for thermostable Bacillus licheniformis α‐amylase was determined under two sets of conditions: an initial rate study over a range of low starch concentrations (1–8%, w/w) in a batch reactor, and a continuous rate study at a high starch concentration of 40% during which a twin‐screw extruder was used as a bioreactor for the first 600 s and the reaction was continued to equilibrium in a batch reactor. The Michaelis–Menten model was found to be sufficient for describing the kinetics at low starch concentrations; however, a modified first‐order model was required at high concentration. There was no evidence of substrate inhibition at the high starch concentration. The rate of product formation, calculated in terms of dextrose equivalent (DE) values, was found to be proportional to the square root of the rate of starch consumption.
Model dyes for optimizing the dyeing of polyamide
Authors: Savarino Piero , Viscardi Guido , Carpignano Rosarina , Barni Ermanno
Published: July 2010

Model disperse azo dyes, containing a salicylic moiety, hydrophobic alkyl chains and usual substituents, allowed the investigation of the effects of these structural variations on dyeing properties.

By combining the results of both equilibrium and rate studies, some interesting structures for practical purposes could be identified.
Aminopropylsilane treatment for the surface of porous glasses suitable for enzyme immobilisation
Authors: Janowski Frank , Fischer Gunter , Urbaniak Wlodzimierz , Foltynowicz Zenon , Marciniec Bogdan
Published: July 2010

During silylation of porous glass with 3‐aminopropyltriethoxysilane, the properties of the carrier affected the concentration of bound amino groups, the formation of aminopolysiloxane mono‐ or multilayer on the surface, and the hydrolytic stability of the layer formed. The influence of the carrier depended on the specific surface area and the size of pores.

In contrast to silylation performed in organic solvents, in aqueous solutions a monolayer of aminopolysiloxane of high hydrolytic stability was formed on the surface of porous glass. Tetraethoxysilane modification of porous glass prior to silylation with aminosilane yields carriers of increased hydrolytic stability. Glucoamylase immobilised on carriers, that were modified in aqueous solutions, exhibit higher enzymatic activity.
Interfacial activity of N‐8‐quinolyl‐p‐dodecylbenzenesulphonamide and the interfacial mechanism of copper extraction
Authors: Szymanowski Jan , Jakubiak Artur , Alejski Krzysztof
Published: July 2010

Various adsorption isotherms were matched to the interfacial tension data in the N‐8‐quinolyl‐p‐dodecylbenzenesulphonamide‐toluene‐water system and used to compute the surface excess isotherms and to predict the reaction orders with respect to extractant for various versions of the interfacial mechanism of copper extraction. Comparison of these reaction orders with those determined experimentally shows that the reaction rate can be limited by the formation of the stable 2:1 complex in the reaction of intermediate 1:1 complex with the sulphonamide molecule both adsorbed at the interface and present in the aqueous film near the interface.
Kinetics and mechanism of Yttrium extraction with three acidic phosphorus extractants
Authors: Ma Enxin , Jiang Peihua , Jin Pinli
Published: July 2010

A mechanic study is reported, which deal with the kinetic aspects of yttrium extraction from HAc‐NaAc‐EDTA media, using three acidic phosphorus extractants (HL), di(2‐ethylhexyl)phosphoric acid (HDEHP), 2‐ethylhexylphosphonic acid mono‐2‐ethylhexyl ester (HEH[EHP]) and di(2,2,4‐trimethylpentyl)phosphinic acid(H[DTMPP]) in n‐octane solution. The initial rates of extraction for these three systems were determined under conditions of energetic stirring or mixing of the two phases. The rate data were correlated as a function of the concentration of the relevant species. From the rate equations magnified image and the interfacial characteristics, the heterogeneous chemical reaction magnified image was established as the rate‐determining step of the overall reaction for the three extractants studied. A mechanism has been proposed for this reaction. The order of the extraction rate was found to be HDEHP>HEH[EHP] > H[DTMPP], and is related to the number of CP bonds in the extractants.
Heat transfer in bubble column and airlift bioreactors: Newtonian and non‐Newtonian fermentation broths
Authors: Kawase Yoshinori , Kumagai Takahiro
Published: July 2010

A theoretical model has been developed for heat transfer in bubble column and airlift bioreactors, which is applicable for Newtonian and non‐Newtonian fermentation media. The proposed model is based on a similarity between heat transfer in gas‐sparged pneumatic reactors and turbulent natural convection. The applicability of the proposed model was discussed using a wide range of experimental data, and good agreement was obtained.
Kinetic model and simulation for catalyst deactivation during dehydrogenation of methylcyclohexane over commercial Pt‐, PtRe‐ and presulfided PtRe‐Al2O3 catalysts
Authors: Chai Mao‐Rong , Kawakami Koei
Published: July 2010

The catalyst deactivation kinetics for the dehydrogenation of methylcyclohexane were studied with Pt‐, PtRe‐, and presulfided Presulfided PtRe‐Al2O3 Catalysts in a fixed‐bed differential reactor. The kinetic analysis was made based on a Langmuir‐Hinshelwood model assuming that the dehydrogenation of methylcyclohexene into methylcyclohexadiene was the rate‐controlling step for the main reaction, and the polymerization of adjacently adsorbed methylcyclohexadiene as coke precursor molecules was the rate‐controlling step for the deactivation reaction. The experimental data for the three catalysts at varying partial pressures of methylcyclohexane and hydrogen were well correlated by the hyperbolic deactivation function derived. The number of active sites involved in the rate‐controlling step of the deactivation was evaluated to be 2.7 in average. The enhanced activity maintenance by the addition of Re as well as sulfur was attributed to a reduction in the concentration of multiple sites occupied by coke precursors adjacently adsorbed, leading to a decrease in the rate constant of the deactivation reaction.
Studies on the dechlorination and detoxification of organochlorine compounds II. Chlorinated cyclodiene insecticides and the polychlorinated insecticide ‘mirex’
Authors: Stojkovski Stojan , Markovec Ladislav M. , Magee Robert J.
Published: July 2010

In the first paper on the dechlorination of organochlorine compounds, results were reported for polychlorinated biphenyls and polychlorinated naphthalenes, using the Ni2B in‐situ catalytic dechlorination technique. In the present study, the work has been extended to the dechlorination and detoxification of some chlorinated polycyclic hydrocarbons belonging to a cyclodiene insecticide group (dieldrin, aldrin and endrin). In addition, a cage‐structured polychlorinated insecticide, ‘mirex’, has also been investigated. During the dechlorination process, intermediates were detected by GC/MS and identified by their characteristic mass fragments and retention in mass.
Ion exchange kinetics in ultra pure water systems
Authors: Harries Richard R.
Published: July 2010

The continuous production of ultra pure water on an industrial scale uses ion exchange mixed beds as a major method of reducing ionic impurities to sub‐μg dm−3 concentrations. Under such demanding operating conditions, particularly the high flow rate and high volume requirements of condensate purification in the power generation industry, it is the kinetics rather than the equilibria of the exchange processes that becomes the main controlling factor. The interactions between anion and cation exchange rates have been studied, particularly with respect to changes in the aqueous phase pH within a bed of exchange resins. The cause and effects of cation exchange resin fouling, both in laboratory tests and in practical applications, have been investigated. The most suitable choice of ion exchange system for ultra pure water production, whether mixed or separate beds, is discussed.
Significance of fluid regime in biological filtration
Authors: Muslu Yilmaz
Published: July 2010

A dispersed flow model previously developed to study substrate utilization in unsaturated media was experimentally verified and its practical application was considered. For this purpose, measurements were made using tap water and a synthetic feed solution. The importance of the change in fluid regime as regards to the simultaneous transport and reaction within biological filters were demonstrated. The effect of drop formation and the breakage of liquid jets inside the filters on substrate utilization was also shown.
Kinetics and mechanism of the vapour phase oxidation of 3‐picoline by nitric oxide over nickel oxide–aluminium oxide catalyst
Authors: Prasad R. , Mathews S. , Garg A.
Published: July 2010

The kinetics of the catalytic transformation of 3‐picoline to 3‐cyanopyridine by nitric oxide (NO) have been investigated over nickel oxide‐aluminium oxide catalyst (2NiO·Al2O3) in a differential flow reactor between 300 and 360°C. A maximum yield of 98% was achieved with a catalyst having a Ni: Al atomic ratio of 1:1 and preheated in the presence of air at 600°C for 24 h. The rate equation Rn = kpknPpPn/(kpPp + knPn) deduced, assuming a steady state involving a two‐stage irreversible oxidation‐reduction process, represented the data most satisfactorily for conversion of 3‐picoline to nicotinonitrile. A tentative mechanism for the reaction is proposed.
Kinetics of removal of p‐toluene sulphonic acid from concentrated solution by granular activated carbon
Authors: Borthakur S. , Srivastava R. C.
Published: July 2010

The removal of p‐toluene sulphonic acid (p‐TSA) from concentrated solution by granular activated carbon (GAC) was studied in batch experiments. The first order rate constant was found to be 5.5010 × 10−5 s−1 for a solution of 1000 mg dm−3. In order to establish the rate limiting step the pore and film diffusion coefficients were calculated from the half time equations. Film diffusion was found to be rate limiting. The average value of the external mass transport rate constant was 2.91 × 10−6 cm s−1. The adsorption isotherm was adequately described by the Langmuir model and belongs to type ‘H’ of Giles' classification.
A mathematical model for the production of biosurfactants by Pseudomonas aeuginosa CFTR‐6: Production of biomass
Authors: Ramana K. Venkata , Charyulu N. C. L. N. , Karanth N. G.
Published: July 2010

The fermentation reaction producing biosurfactant using Pseudomonas aeruginosa CFTR‐6 was studied. The progress of the bioreaction was monitored in terms of biomass production, product formation and substrate consumption in shake flask experiments using different initial sugar concentrations. A logistic model for biomass growth was found to be satisfactory. Average estimates of the specific growth rate, biomass yield coefficient and maintenance coefficients were obtained.
Computational fluid dynamics and its application to transport processes
Authors: Collins M. W. , Ciofalo M.
Published: July 2010

Fluid transport behaviour is of great importance within the chemical process industry and in biotechnology. The complexity of this behaviour, reflected in the nature of the fundamental partial differential equations which describe it analytically, means that it has to be treated by numerical methods.

In this paper the basic equations are given, and the approaches necessary to treat laminar and turbulent flows are carefully explained. As digital computers have increased in size, so has the comprehensiveness of the problems which can be treated, and the development of typical computer programs is described.

Problems of accuracy and experimental validation are also surveyed, and it is shown that recent developments in whole‐field optical measurement methods, and image and data processing are all involved here. Then, a review of work at City University is shown to comprise typical examples of applications to engineering situations and biotechnology problems. Chosen instances of the former are flow and heat transfer behaviour for convective enhancement caused by roughness elements, and the design balancing of a thermosyphon. The latter include such diverse studies as blood flows in arterial bifurcations, and heat and mass transport in grain storage. They involve the three‐dimensional and transient capabilities of current codes, and their applicability to non‐standard geometries.
Physico‐chemical characterization of the main factors affecting the mode of action of liver alcohol dehydrogenase immobilized on nylon tubing
Authors: Roig M. G. , Bello J. B. , de Cells C. , Cachaza J. M. , Kennedy J. F.
Published: July 2010

Alcohol dehydrogenase (ADH) from horse liver (EC 1.1.1.1), cross‐linked through the bifunctional reactive glutaraldehyde, onto nylon tubing was immobilized (35 μg cm−2 internal surface of nylon tubing). ADH inactivation kinetics of the immobilized enzyme are of first order (t1/2 = 84.3 h, k = 5.2 × 10−3 h−1 at 5°C; t1/2 = 2.6h, k = 0.26 h−1 at 50°C). The activity versus pH profile points to a smaller effect of pH on the activity of the enzyme, which is the case of ADH in solution, explicable on the basis of limitations to proton diffusion towards/from the support. A limiting effect to free external diffusion of the substrate (products) towards/from the support was observed; this effect seems to determine the effective kinetic behaviour of immobilized ADH.
The recovery of fructose from inverted sugar beet molasses using continuous chromatography
Authors: Barker Philip E. , Joshi Ketan
Published: July 2010

The continuous chromatographic separation of inverted beet molasses resulting in a fructose rich product and a product containing glucose and other non‐sugars was carried out using a semi‐continuous countercurrent chromatographic refiner (SCCR6), consisting of ten 10.8 cm diameter by 75 cm long stainless steel columns packed with a calcium charged 8% cross‐linked polystyrene resin, zerolit SRC14.

It was found that cations present in beet molasses displaced calcium ions from the resin resulting in poor separation of the glucose and fructose. Three methods of maintaining the calcium form of the resin during the continuous operation of the equipment were established. Passing a solution of calcium nitrate through the purge column for half a switch period was found to be most effective as there was no contamination of the main fructose rich product and the product concentrations were increased by 50%.
A bioseparation process for removing lead(II) ions from waste water by using C. vulgaris
Authors: Aksu Zümriye , Kutsal Tülin
Published: July 2010

Biosorption of heavy metals by microbial cells has been recognized as a potential alternative to existing technologies for removing heavy metals from industrial waste waters. Many aquatic microorganisms, such as algae, can take up dissolved metals from their surroundings to their cells. In this study, the adsorption of lead(II) ions was investigated in a single‐staged batch reactor. Chlorella vulgaris, a green alga, was used as the sorbent. The sorption phenomenon was expressed by the Freundlich adsorption isotherm and this expression was used for the calculation of residual or adsorbed metal ion concentration at equilibrium (Ceq or Cx,eq) at a given ‘volume of waste water containing heavy metal ion/quantity of alga (V0/X0)’ ratio in a single‐staged batch reactor. Experimental Ceq and Cx,eq values were compared to calculated ones. Applications in waste water treatment for lead(II) removal have been suggested.
Inhibition of growth and acetate uptake by ammonia in batch anaerobic digestion
Authors: Poggi‐Varaldo Héctor M. , Tingley Judy , Oleszkiewicz Jan A.
Published: July 2010

Ammonia inhibition of unacclimated anaerobic mesophilic mixed cultures was studied in batch mode. Bacterial growth rate and specific acetate‐uptake rate were affected by the concentration of un‐ionised ammonia (UAN) in a three‐stage pattern: initial inhibition, plateau and final inhibition stage. The un‐competitive inhibition model provided the most reasonable data fit. The stage pattern of inhibition suggested that more than one mechanism of UAN inhibition are acting on the mixed culture. The effects of UAN on the length of initial lag‐time also followed a three‐staged curve. High concentration of UAN resulted in acetate release. The biological basis and origin of the acetate release were not determined.
Urease immobilized on chitosan membrane. Inactivation by heavy metal ions
Authors: Krajewska Barbara
Published: July 2010

Heavy metal ion inactivation of urease covalently immobilized on glutaraldehyde‐pretreated chitosan membrane was compared with that of free urease. The relative toxicity sequence of metal ions toward free urease: Hg2+ > Ag+ > Cu2+ > Ni2+ > Cd2+ > Zn2+ > Co2+ > Fe2+ > Pb2+ > Mn2+ correlates well with metal sulfide solubility product constants (except for Fe3+). The stability of urease against metal ion inactivation was considerably improved after immobilization: Ni2+, Co2+, Fe3+, Pb2+ and Mn2+ do not inactivate the immobilized urease in the range of concentrations at which free urease is thoroughly inactivated. Hg2+, Ag+, Cu2+, Zn2+ and Cd2+ inactivate the enzyme at considerably higher concentrations. The improved stability may be a consequence of structural changes introduced to the enzyme by the immobilization and of chelating effect of chitosan.