J. Rynkowski - Academia.edu (original) (raw)
Papers by J. Rynkowski
Portugaliae Electrochimica Acta, 2022
Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylen... more Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylenediamine (THPrED) are used relatively often in galvanic processes. Tetra-substituted derivatives, such as N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine, (THEtED) are quite biologically stable and hardly degradable. In recent years, much attention has been devoted to electrochemical oxidation, using anodes with a high over-potential of O2 evolution, such as the boron-doped diamond (BDD). DETA and THPrED electrochemical treatment using a BDD anode was herein studied. The degradation efficiency of the amines was evaluated under different current intensities and reaction times. To determine the products formed in the oxidation process, ion chromatography (IC) was used. A high decrease in the current between the first and the second CV scan indicated the polymer film formation on the BDD electrode surface. Hydroxyl radicals formed at a potential of about 2 V and higher caused further oxidation of the electrode reaction products. It was found that NH4 + , CH3-COOH, N2, EDA, CO2 and NO3-were formed in a short reaction time, and at low current intensity. The mineralization occurred during substrates electrolysis, due to rapid DETA and THPrED decomposition. After 180 min of reaction, αTOC and αN values for DETA were 94% and 18%, respectively. For THPrED, αTOC was 98.6% and αN was 43.6%. Therefore, the electrochemical approach was considered a very promising method in practical application for the treatment of wastewater containing amines.
Studies in Surface Science and Catalysis, 1999
ABSTRACT
Radiation Physics and Chemistry, 2013
We determined the minimum hydrotrope concentration (MHC) for SCS. c We analyzed the SCS reactions... more We determined the minimum hydrotrope concentration (MHC) for SCS. c We analyzed the SCS reactions with oxidizing and reducing species. c The rate constants for the oxidation and reduction of SCS were given.
Kinetics and Catalysis, 2007
Hydrogenation of crotonaldehyde in a gas phase over Pt/α-GeO2 catalysts was investigated. The sys... more Hydrogenation of crotonaldehyde in a gas phase over Pt/α-GeO2 catalysts was investigated. The systems were characterized by BET, XRD, TPR, TEM, ToF-SIMS, and FTIR methods. The optimum pretreatment parameters were studied. The best catalytic performance shows the catalyst 5 wt % Pt/α-GeO2 (69% selectivity to crotyl alcohol at 200 μmol s−1 g Pt −1 activity and 10% conversion of crotonaldehyde).
Journal of Electroanalytical Chemistry, 2014
Electroreduction behavior of acetylsalicylic acid (ASA) was investigated at platinum electrode us... more Electroreduction behavior of acetylsalicylic acid (ASA) was investigated at platinum electrode using the cyclic voltammetry method. An effect of scan rate, ASA concentration and pH on electrode reaction was determined. The process is diffusion-controlled. Parameters of ASA electroreduction, i.e., rate constant, charge transfer coefficient and diffusion coefficient, were calculated. The ASA electroreduction is quasireversible and proceeds in two steps. This process is preceded by substrate hydrolysis resulting in the formation of salicylic (SA) and acetic (AA) acid. Hydrolysis products are electrochemically reduced. In the first and second step, electroreduction of SA and AA proceeds, respectively. Possible mechanism of ASA electroreduction was proposed.
Electrochimica Acta, 2013
ABSTRACT
Catalysis Today, 2006
The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts... more The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts was investigated for supports containing 50wt.% of MCM-41. A series of catalysts was characterized by different techniques (SBET, TPD-NH3, TPR, SEM, XPS) and tested in dibenzothiophene (DBT) conversion. On the surface of the catalysts containing mesoporous materials, agglomerations of the Mo oxo-species were observed.
Medical science monitor : international medical journal of experimental and clinical research, 2010
Studies suggest dopamine nervous systems are involved in the pathogenesis of autistic disorder. Q... more Studies suggest dopamine nervous systems are involved in the pathogenesis of autistic disorder. Quantification of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) can be a very important tool in the study of disorders of dopamine metabolism in autistic children. The urine specimens were collected from 20 autistic children and 36 neurologically normal children. Urinary HVA and VMA were simultaneously analyzed by gas chromatography-mass spectrometry. The method involves extraction of HVA and VMA from urinary samples and derivatization to N,O-bis(trimethylsilyl)trifluoroacetamide derivatives. The detection limits are 0.15 microg/mL and 0.23 microg/mL for VMA and HVA, respectively. The levels of HVA and VMA were higher in the urine of autistic children (28.8+/-15.5 micromol/mmol creatinine and 22.2+/-13.0 micromol/mmol creatinine, respectively) compared with those of the generally healthy children (4.6+/-0.7 micromol/mmol creatinine for HVA and 3.8+/-0.6 micromol/mmol cre...
Catalysts, 2020
A goal of this work was to investigate the influence of the preparation procedure and activation ... more A goal of this work was to investigate the influence of the preparation procedure and activation conditions (reduction temperature and reducing medium: pure hydrogen (100% H2) or hydrogen-argon mixture (5% H2-95% Ar)) on the activity of Co-containing BEA zeolites in Fischer–Tropsch synthesis. Therefore, a series of CoBEA zeolites were obtained by a conventional wet impregnation (Co5.0AlBEA) and a two-step postsynthesis preparation procedure involving dealumination and impregnation steps (Co5.0SiBEA). Both types of zeolites were calcined in air at 500 °C for 3 h and then reduced at 500, 800 and 900 °C for 1 h in 100 % H2 and in 5% H2–95% Ar mixture flow. The obtained Red-C-Co5.0AlBEA and Red-C-Co5.0SiBEA catalysts with various physicochemical properties were tested in Fischer–Tropsch reaction. Among the studied catalysts, Red-C-Co5.0SiBEA reduced at 500 °C in pure hydrogen was the most active, presenting selectivity to liquid products of 91% containing mainly C7–C16 n-alkanes and iso...
Portugaliae Electrochimica Acta, 2022
Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylen... more Ethylenediamine (EDA), diethylenetriamine (DETA) and N,N,N',N'-tetrakis (2-hydroxypropyl) ethylenediamine (THPrED) are used relatively often in galvanic processes. Tetra-substituted derivatives, such as N, N, N ', N'-tetrakis (2-hydroxyethyl) ethylenediamine, (THEtED) are quite biologically stable and hardly degradable. In recent years, much attention has been devoted to electrochemical oxidation, using anodes with a high over-potential of O2 evolution, such as the boron-doped diamond (BDD). DETA and THPrED electrochemical treatment using a BDD anode was herein studied. The degradation efficiency of the amines was evaluated under different current intensities and reaction times. To determine the products formed in the oxidation process, ion chromatography (IC) was used. A high decrease in the current between the first and the second CV scan indicated the polymer film formation on the BDD electrode surface. Hydroxyl radicals formed at a potential of about 2 V and higher caused further oxidation of the electrode reaction products. It was found that NH4 + , CH3-COOH, N2, EDA, CO2 and NO3-were formed in a short reaction time, and at low current intensity. The mineralization occurred during substrates electrolysis, due to rapid DETA and THPrED decomposition. After 180 min of reaction, αTOC and αN values for DETA were 94% and 18%, respectively. For THPrED, αTOC was 98.6% and αN was 43.6%. Therefore, the electrochemical approach was considered a very promising method in practical application for the treatment of wastewater containing amines.
Studies in Surface Science and Catalysis, 1999
ABSTRACT
Radiation Physics and Chemistry, 2013
We determined the minimum hydrotrope concentration (MHC) for SCS. c We analyzed the SCS reactions... more We determined the minimum hydrotrope concentration (MHC) for SCS. c We analyzed the SCS reactions with oxidizing and reducing species. c The rate constants for the oxidation and reduction of SCS were given.
Kinetics and Catalysis, 2007
Hydrogenation of crotonaldehyde in a gas phase over Pt/α-GeO2 catalysts was investigated. The sys... more Hydrogenation of crotonaldehyde in a gas phase over Pt/α-GeO2 catalysts was investigated. The systems were characterized by BET, XRD, TPR, TEM, ToF-SIMS, and FTIR methods. The optimum pretreatment parameters were studied. The best catalytic performance shows the catalyst 5 wt % Pt/α-GeO2 (69% selectivity to crotyl alcohol at 200 μmol s−1 g Pt −1 activity and 10% conversion of crotonaldehyde).
Journal of Electroanalytical Chemistry, 2014
Electroreduction behavior of acetylsalicylic acid (ASA) was investigated at platinum electrode us... more Electroreduction behavior of acetylsalicylic acid (ASA) was investigated at platinum electrode using the cyclic voltammetry method. An effect of scan rate, ASA concentration and pH on electrode reaction was determined. The process is diffusion-controlled. Parameters of ASA electroreduction, i.e., rate constant, charge transfer coefficient and diffusion coefficient, were calculated. The ASA electroreduction is quasireversible and proceeds in two steps. This process is preceded by substrate hydrolysis resulting in the formation of salicylic (SA) and acetic (AA) acid. Hydrolysis products are electrochemically reduced. In the first and second step, electroreduction of SA and AA proceeds, respectively. Possible mechanism of ASA electroreduction was proposed.
Electrochimica Acta, 2013
ABSTRACT
Catalysis Today, 2006
The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts... more The influence of mesoporous materials on the properties and HDS activity of Mo and NiMo catalysts was investigated for supports containing 50wt.% of MCM-41. A series of catalysts was characterized by different techniques (SBET, TPD-NH3, TPR, SEM, XPS) and tested in dibenzothiophene (DBT) conversion. On the surface of the catalysts containing mesoporous materials, agglomerations of the Mo oxo-species were observed.
Medical science monitor : international medical journal of experimental and clinical research, 2010
Studies suggest dopamine nervous systems are involved in the pathogenesis of autistic disorder. Q... more Studies suggest dopamine nervous systems are involved in the pathogenesis of autistic disorder. Quantification of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) can be a very important tool in the study of disorders of dopamine metabolism in autistic children. The urine specimens were collected from 20 autistic children and 36 neurologically normal children. Urinary HVA and VMA were simultaneously analyzed by gas chromatography-mass spectrometry. The method involves extraction of HVA and VMA from urinary samples and derivatization to N,O-bis(trimethylsilyl)trifluoroacetamide derivatives. The detection limits are 0.15 microg/mL and 0.23 microg/mL for VMA and HVA, respectively. The levels of HVA and VMA were higher in the urine of autistic children (28.8+/-15.5 micromol/mmol creatinine and 22.2+/-13.0 micromol/mmol creatinine, respectively) compared with those of the generally healthy children (4.6+/-0.7 micromol/mmol creatinine for HVA and 3.8+/-0.6 micromol/mmol cre...
Catalysts, 2020
A goal of this work was to investigate the influence of the preparation procedure and activation ... more A goal of this work was to investigate the influence of the preparation procedure and activation conditions (reduction temperature and reducing medium: pure hydrogen (100% H2) or hydrogen-argon mixture (5% H2-95% Ar)) on the activity of Co-containing BEA zeolites in Fischer–Tropsch synthesis. Therefore, a series of CoBEA zeolites were obtained by a conventional wet impregnation (Co5.0AlBEA) and a two-step postsynthesis preparation procedure involving dealumination and impregnation steps (Co5.0SiBEA). Both types of zeolites were calcined in air at 500 °C for 3 h and then reduced at 500, 800 and 900 °C for 1 h in 100 % H2 and in 5% H2–95% Ar mixture flow. The obtained Red-C-Co5.0AlBEA and Red-C-Co5.0SiBEA catalysts with various physicochemical properties were tested in Fischer–Tropsch reaction. Among the studied catalysts, Red-C-Co5.0SiBEA reduced at 500 °C in pure hydrogen was the most active, presenting selectivity to liquid products of 91% containing mainly C7–C16 n-alkanes and iso...