Papers by Stanislaw Ledakowicz
The kinetics of gasification of char derived from sewage sludge
Journal of Thermal Analysis and Calorimetry, 2011
Gasification of char derived from sewage sludge was studied under different oxidizing atmospheres... more Gasification of char derived from sewage sludge was studied under different oxidizing atmospheres containing CO2, O2 or H2O. The gasification tests were carried out in thermobalance at different temperatures and oxidizing reagent concentrations. The most efficient were the gaseous mixtures containing oxygen. The reaction took place at temperature 400–500 °C, whilst in the case of CO2 and steam much higher temperatures
Energetyczne wykorzystanie osadów ściekowych i odpadów z gospodarstw domowych w procesie fermentacji metanowej
Przemysl Chemiczny, 2003
Transformed roots are also called transgenic roots or due to their appearance – hairy roots. Tran... more Transformed roots are also called transgenic roots or due to their appearance – hairy roots. Transformed roots are obtained by infection of plants or parts of them with soil bacteria, Agrobacterium rhizogenes. Genetically transformed roots are characterised by rapid and stable growth of biomass, genetic stability, and stable biosynthesis of metabolites. Hairy roots can be an alternative source of many economically important chemicals like enzymes, pigments, flavours and especially bioactive pharmaceuticals. Cultures of transformed roots are comparatively easy to cultivate in shaking flasks. Application of flasks does not allow to obtain great amount of biomass. There is a necessity of scaling up the culture using bioreactors. The first attempts of scaling up the culture were connected with bioreactors designed for microbiological processes. However, these bioreactors are inadequate for hairy roots cultures. Some promising results were achieved in the case of using mist bioreactor. T...
Biodegradation, decolourisation and detoxification of textile wastewater enhanced by advanced oxidation processes
Journal of biotechnology, 2001
Recently, an increasing application of so called advanced oxidation processes (AOPs) to industria... more Recently, an increasing application of so called advanced oxidation processes (AOPs) to industrial wastewater has been observed. In particular, an integrated approach of biological and chemical treatment of wastewater is advantageous conceptually. The subject of our study was synthetic wastewater, simulating effluents from knitting industry. The wastewater contained components that are very often used in Polish textile industry: an anionic detergent Awiwaz KG conc., a softening agent Tetrapol CLB and an anthraquinone dyestuff-Acid Blue 40, CI 2125. The toxicity of the detergents and the dye was determined in terms of effective concentration EC50 using mixed cultures of activated sludge as well as pure culture of luminescent bacteria Vibrio fischerii NRRLB-11177. The dye did not undergo biodegradation without AOPs pretreatment, therefore a degree of its removal (decolourisation) by the AOPs has been determined and its bio-sorption properties on the flocks of activated sludge have bee...
Degradation of household biowaste in reactors
Journal of biotechnology, 2001
Household derived biowaste was degraded by biological methods. The system involves the combined m... more Household derived biowaste was degraded by biological methods. The system involves the combined method of low-solids (up to 10% w/v of total solids (TS)) anaerobic digestion and aerobic degradation for the recovery of energy (biogas) and the production of fine humus-like material which can be used as a soil amender or a substrate for further thermal treatment (pyrolysis, gasification). The performance of batch and continuous processes carried out in bioreactors (stirred tank reactor, air-lift) of working volume 6 and 18 dm(3), at different temperatures (25-42 degrees C) was monitored by reduction of TS, volatile solids, chemical oxygen demand, total organic carbon, C/N in time. The application of continuous process with recirculation (33%) caused that for residence time of 8-16 h the obtained degree of organic load reduction was similar to that obtained after 72-96 h of the batch process. The experimental data of batch aerobic degradation was also subjected to kinetic analysis. The ...
Kinetyka nitryfikacji i denitryfikacji odcieków ze składowiska odpadów "Lublinek" w Łodzi
Inzynieria Chemiczna I Procesowa, 2004
Space-time yield of suspended-catalyst three-phase reactors in synthesis gas refining processes
The authors have studied a suspended-catalyst three-phase reactor which is used for the process o... more The authors have studied a suspended-catalyst three-phase reactor which is used for the process of synthesis of methanol and the Fischer-Tropsch reaction. On the basis of experimental data obtained in a laboratory set-up they have shown that reactor operation is influenced by gas velocity. A satisfactory agreement has been found between experiment and calculation by the well-known model of synthesis gas refining processes in the reactor considered.
CO2 gasification of char from spent mushroom substrate in TG-MS system
Journal of Thermal Analysis and Calorimetry, 2019
Gasification of the char obtained from the spent substrate after mushroom cultivation was carried... more Gasification of the char obtained from the spent substrate after mushroom cultivation was carried out in a thermobalance connected to a mass spectrometer in the temperature range from 200 to 950 °C and CO2 concentration from 5 to 100 vol%. Under non-isothermal conditions, in addition to the char gasification process, both carbonation and calcination reactions occurred. The investigation of gasification kinetics in CO2 was carried out under isothermal conditions. The rate of gasification reaction was determined from the shrinking core model, and kinetic constant has been calculated from Langmuir–Hinshelwood kinetics. On the basis of the conducted research, it was observed that the saturation of active sites on the char particles occurred above 50 vol% CO2, regardless of temperature. The analysis of gas composition indicates CO as the main product of gasification.
Ocena toksyczności benzyloparabenu przed i po rozkładzie fotochemicznym
Bacterial leaching of nickel and cobalt from pentlandite
Fischer‐tropsch synthesis in bubble column slurry reactors on FE/K‐catalyst
Canadian Journal of Chemical Engineering, 1986
Fischer-Tropsch synthesis (FTS) on K promoted Fe catalyst was studied in three bubble column slur... more Fischer-Tropsch synthesis (FTS) on K promoted Fe catalyst was studied in three bubble column slurry reactors (BCSR) of 2.5, 5, and 10 cm diameter. The objective was to check data reproducibility under conditions of arbitrary alterations of various parameters. First order rate constants evaluated on the basis of appropriate slurry reactor models were chosen as an approximate measure to characterize data reproducibility and catalyst activity. It was found that rate constants and hence reproducibility may differ by a factor of two if different batches and precipitations of catalyst are considered. Within the parameter ranges covered in this study this rule of thumb is valid irrespective of reactor diameter, type of sparger, catalyst concentration, temperature, pressure, and gas flow rate. The rate constants compare well with literature data. On a etudie la synthese Fischer-Tropsch sur un catalyseur au Fe activee par le K dans trois reacteurs a colonnes a bulles et suspension dont les d...
A macrokinetic modelling of the biosynthesis of lovastatin by Aspergillus terreus
Journal of biotechnology, 2007
In this work a simple kinetic model to describe the biosynthesis of lovastatin by Aspergillus ter... more In this work a simple kinetic model to describe the biosynthesis of lovastatin by Aspergillus terreus ATCC 20542 was proposed. Several series of experiments were conducted at different media compositions. The concentrations of C- and N-sources were changed over a wide range and so were the initial biomass concentrations. From these runs the relationships ruling the substrates uptake, biomass and product formation were learnt. Lovastatin biosynthesis appeared to be partly growth associated. The inhibitive effect of organic nitrogen on lovastatin biosynthesis was found and lactose appeared to be an important limiting substrate in the formation of lovastatin. The parameters of the model were evaluated on the basis of the kinetic data obtained in the separate experiments made in triplicate at two chosen media compositions. Other results obtained at different media compositions were independent of the ones mentioned above and used for the verification of the model. The validity of the mo...
Thermal processing of sewage sludge by drying, pyrolysis, gasification and combustion
Water science and technology : a journal of the International Association on Water Pollution Research, 2001
Thermal processing of sewage sludge including drying, pyrolysis and gasification or combustion ma... more Thermal processing of sewage sludge including drying, pyrolysis and gasification or combustion may be an alternative to other ways of utilising it. In this paper thermogravimetric analysis (TGA) was employed in the investigation of thermal decomposition of sewage sludge. The kinetic parameters of drying, pyrolysis and gasification or combustion of sewage sludge have been determined in an inert-gas (argon) and additionally some series of the sludge decomposition experiments have been carried out in air, in order to compare pyrolysis and combustion. The pyrolysis char has been gasified with carbon dioxide. A typical approach to the kinetics of thermal decomposition of a solid waste is to divide the volatile evolution into a few fractions (lumps), each of which is represented by a single first-order reaction. If these lumps are assumed to be non-interacting and evolved by independent parallel reactions the first-order kinetic parameters such as activation energy Ei and pre-exponential ...
Photochlorination of tetrachloroethene in carbon tetrachloride solutions
Journal of Physical Organic Chemistry, 1993
Validation of the mechanism of tetrachloroethene photochlorination at low C2Cl4 concentrations wa... more Validation of the mechanism of tetrachloroethene photochlorination at low C2Cl4 concentrations was investigated. The reaction was examined in carbon tetrachloride solution. For initial tetrachloroethene concentrations below 2 mol I−1, the solvent participates in a free-radical chain photochlorination. The presence of CCl4 disturbs the course of this particular chain reaction and influences the duration of the induction period.
Uwodornienie tlenku węgla do wyższych alkoholi alifatycznych w reaktorze trójfazowym gaz-ciecz-ciało stałe
Inzynieria Chemiczna I Procesowa, 1998
Kinetic model of fischer-tropsch synthesis selectivity in the slurry phase
Chemical Engineering Science, 1992
The objective of this study was to develop a kinetic model to describe the selectivity typical of... more The objective of this study was to develop a kinetic model to describe the selectivity typical of iron-based Fischer-Tropsch catalysts and to compare the simulations of the process in the slurry stirred tank reactors with experimental data. The model accounts for the formation of paraffins and olefins and also for the water-gas shift and secondary hydrogenation of olefins. Non-Schulz-Flory distribution was obtained due to olefin readsorption followed by chain growth. The simulation results show fair agreement with experimental data obtained in a laboratory stirred tank reactor with the use of a commercial iron-based catalyst Ruhrchemie LP 33/81 suspended in the molten octacosane.
Kinetics of tetrachloroethene photochlorination
Chemical Engineering Science, Jul 1, 1993
ABSTRACT
Inżynieria Chemiczna i Procesowa/Chemical and Process Engineering, Feb 27, 2024
The paper focused on the co-production of high-value-added product thermostable C-phycocyanin (C-... more The paper focused on the co-production of high-value-added product thermostable C-phycocyanin (C-PC) and biomass, further utilized in pyrolysis. The photobiosynthesis of C-PC was carried out by the thermophilic cyanobacteria Synechococcus PCC6715 cultivated in the helical and flat panel photobioreactors (PBR). Despite the application of different inorganic carbon sources, both PBRs were characterized by the same growth efficiency and similar C-PC concentration in biomass. To release the intracellular C-PC the biomass was concentrated and disintegrated by the freeze-thaw method. The crude C-PC was then further purified by foam fractionation (FF), aqueous two-phase extraction (ATPE), membrane techniques (UF) and fast protein liquid chromatography (FPLC). Each of the tested methods can be used separately; however, from a practical and economic point of view, a three-stage purification system (FF, FPLC and UF) was proposed. The purity ratio of the final C-PC was about 3.9, which allows it to be classified as a reactive grade. To improve the profitability of 3G biorefinery, the solid This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the version of record. Please cite this article as
Biodegradacja odcieków z wysypiska odpadów komunalnych "Lublinek" w Łodzi, wspomagana metodami pogłębionego utleniania
Wykorzystanie procesów pogłębionego utleniania do rozkładu niejonowego środka powierzchniowo czynnego Triton X-114
Przemysl Chemiczny, 2001
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Papers by Stanislaw Ledakowicz