Effect of the concentration of 5,5'-dithiobis(2-nitrobenzoic acid) on parameters of the kinetics of its chemisorption on thiol derivatives of cellulose

1986 ◽  
Vol 51 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Albert Breier ◽  
Peter Gemeiner ◽  
Milan J. Beneš
Keyword(s):  
Ethyl Cellulose ◽  
Chemical Structure ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Cellulose Derivatives ◽  
Experimental Conditions ◽  
Nitrobenzoic Acid ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Sorbate Concentration

Equations describing the dependence of parameters of sorption kinetics on the sorbate concentration have been determined. The validity of the equations has been verified for the chemisorption of 5,5'-dithiobis(2-nitrobenzoic acid) on bead O-(2-mercaptoethyl)-, O-(3-mercapto-2-hydroxy-propyl)- and O-[2-(4-mercaptophenylsulfonyl)ethyl]cellulose. Isothermic constants obtained from the equations can be calculated also under experimental conditions unfavourable for their determination. These constants may be utilized for characterizing relations between the chemical structure of cellulose derivatives and the sorption process. The equation which provides a complete time-concentration description of sorption is suggested.

Sorption and Sorption Kinetics of Ethylbenzene in MFI-Type Zeolites Studied by a Barometric Technique

1999 ◽  
Vol 64 (3) ◽  
pp. 483-494 ◽  
Author(s):  
Richard Schumacher ◽  
Hellmut G. Karge
Keyword(s):  
Critical Concentration ◽  
Sharp Decrease ◽  
Isosteric Heat ◽  
Critical Value ◽  
Sorption Kinetics ◽  
Experimental Conditions ◽  
Heats Of Adsorption ◽  
The Relationship ◽  
Kinetics Of ◽  
Sorbate Concentration

The sorption and sorption kinetics of ethylbenzene in H-ZSM-5 zeolites was studied varying the experimental conditions over a broad range of temperature and concentration. Isotherms and heats of adsorption as well as intracrystalline diffusivities have been determined. The isosteric heat of adsorption decreases with increasing sorbate loading due to repulsive sorbate-sorbate interaction. The diffusivity remains independent of sorbate concentration at loadings lower than a critical value of about four molecules per unit cell, while a sharp decrease is observed at higher loadings. The critical concentration slightly depends on the temperature. The relationship between diffusivity, concentration and temperature can be tentatively interpreted in terms of a complex sorbate-sorbent interaction.

scholarly journals Synthesis of New Antibiotics Derivatives by the Photocatalytic Method: A Screening Research

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1102
Author(s):  
Wojciech Baran ◽  
Ewa Masternak ◽  
Dominika Sapińska ◽  
Andrzej Sobczak ◽  
Ewa Adamek
Keyword(s):  
Quantum Yield ◽  
Biologically Active ◽  
Quantum Yields ◽  
Photocatalytic Process ◽  
Experimental Conditions ◽  
New Antibiotics ◽  
Photocatalytic Reactions ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Uva Radiation

The aim of our study was to assess the possibility of using the photocatalytic process conducted in the presence of TiO2 to obtain new stable derivatives of antibacterial drugs. The possibility of introducing hydroxyl, chlorine, or bromide groups into antibiotics molecules was investigated. The experiments were conducted in aqueous solutions in the presence of TiO2-P25 as a photocatalyst, Cl− and Br- ions, and antibiotics belonging to eight different chemical classes. All experiments were initiated by UVa radiation. The kinetics of photocatalytic reactions and their quantum yield were determined, and the stable products were identified. All of the antibiotics used in the experiments underwent a photocatalytic transformation, and the quantum yields were in the range from 0.63 to 22.3%. The presence of Br- or FeCl3 significantly increased the efficiency of the photocatalytic process performed in the presence of TiO2, although Br- ion also acted as an inhibitor. Potentially biologically active chlorine derivatives from Trimethoprim, Metronidazole, Chloramphenicol, and bromine derivatives from Trimethoprim, Amoxicillin were obtained under experimental conditions. The potentially inactive halogen derivatives of Sulfamethoxazole and hydroxyl derivatives described in the literature were also identified.

scholarly journals Effect of Additives on the Sorption Kinetics of a Silica Gel Bed in Adsorption Chiller

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1083
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Łukasz Mika ◽  
Agata Mlonka-Medrala ◽  
Marcin Sowa ◽  
...  
Keyword(s):  
Silica Gel ◽  
Adsorbed Water ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Experimental Results ◽  
Process Time ◽  
Vapor Sorption ◽  
Dynamic Vapor Sorption ◽  
Adsorption Chiller ◽  
Kinetics Of

The article presents experimental results of the metal-based and carbon nanotube additives influence on sorption kinetics of a silica-gel-based adsorption bed in an adsorption chiller. The purpose of the doping is to improve the efficiency of sorption processes within the bed by use of metallic and non-metallic additives characterized by higher thermal diffusivity than basic adsorption material. The higher the thermal conductivity of the bed, the faster the sorption processes take place, which directly translates into greater efficiency of the refrigerator. In this study, sorption kinetics of pure silica gel sorbent doped with a given amount of aluminum (Al) and copper (Cu) powders and carbon nanotubes (CNT) were analyzed. The tests were performed on DVS Dynamic Gravimetric Vapor Sorption System apparatus used for dynamic vapor sorption measurements. A decrease in the amount of adsorbed water was observed with an increase in the mass share of the additives in the performed studies. Experimental results show that, CNTs seems to be the most promising additive as the sorption process time was reduced with the smallest decrease in water uptake. Any significant reduction of adsorption time was noted in case of the Al addition. Whereas, in case of Cu doping, delamination of the mixture was observed.

scholarly journals Uptake Capacity of Pb2+ by Sulphonated Biomass of Cicer arietinum: Batch Studies

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
A. A. Kale
Keyword(s):  
Cicer Arietinum ◽  
Sorption Process ◽  
Order Model ◽  
Experimental Conditions ◽  
Batch Mode ◽  
Batch Studies ◽  
Intraparticle Diffusion Model ◽  
Pseudo Second Order ◽  
Modeling Data ◽  
Kinetics Of

Fundamental investigation on the removal of heavy metal Pb2+ from aqueous solutions by sulphonated biomass (S-III) of Cicer arietinum is conducted in batch mode. The effect of different parameters such as contact time, sorbent dose, pH and temperature has been studied. Adsorption kinetic modeling data were found. The kinetics of biosorption results shows that sorption process is well explained by pseudo-second-order model with determination coefficients 0.998 for S-III under all experimental conditions. The sorption mechanism was determined by Weber and Morris intraparticle diffusion model. Thermodynamic parameters, namely, KD and ΔG,have also been calculated to determine the spontaneity of the process.

Sorption and desorption kinetics of Np(V) on magnetite and hematite

2000 ◽  
Vol 88 (8) ◽  
Author(s):  
K. Nakata ◽  
S. Nagasaki ◽  
S. Tanaka ◽  
Y. Sakamoto ◽  
T. Tanaka ◽  
...  
Keyword(s):  
Crystalline Phase ◽  
Acidic Solution ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Chemical Form ◽  
Alkaline Solutions ◽  
Desorption Kinetics ◽  
Chemical Forms ◽  
Kinetics Of ◽  
Desorption Method

Sorption kinetics of Np(V) on magnetite and hematite were investigated, and a sequential desorption method was applied to investigate changes in the chemical form of Np sorbed according to the amount of time they were in contact with the Np solution. It was found that the sorption process consists of fast sorption and slow sorption which reaches equilibrium in 1 h. According to the desorption results, it was conjectured (i) that fast sorption is attributable to sorption on/into the surface and non-crystalline phases of iron oxides for magnetite and hematite in both acidic and alkaline solutions, (ii) that sorption on/into the crystalline phase also contributes to fast sorption for hematite in an alkaline solution, and (iii) that slow sorption represents sorption into the crystalline phase of magnetite in both acidic and alkaline solutions and that of hematite in an acidic solution. From the results of sorption and desorption kinetics, it was concluded that the equilibrium between various chemical forms of sorbed Np was achieved in about 1 week, although the amount of sorbed Np reached an equilibrium in only 1 h.

scholarly journals Equilibrium and Kinetic Study of Ammonium Sorption by Raphia farinifera

2019 ◽  
Vol 230 (10) ◽  
Author(s):  
Paweł Staroń ◽  
Paulina Sorys ◽  
Jarosław Chwastowski
Keyword(s):  
Chemical Nature ◽  
Sorption Process ◽  
Sorption Kinetics ◽  
Second Order ◽  
Isotherm Models ◽  
Mechanism Analysis ◽  
Order Model ◽  
Sorption Model ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract The study investigated the sorption capacity of biosorbent-raphia sp. against ammonia. Raphia fibers were used without and with the modification of its surface with NaCl, NaNO3, and K2SO4. The data was analyzed in the state of equilibrium using four isotherm models such as Langmuir, Freudlich, Temkin, and Dubinin-Radushkevich. The equilibrium of ammonia sorption for all studied systems was best described by the Freudlich isotherm model. On its basis, it can be assumed that the studied process is of chemical nature, which results from the value of the coefficient 1/n < 1. In order to confirm the sorption mechanism, analysis of the kinetics of the ammonia sorption process on raphia fibers was performed. Four kinetic models of sorption were calculated: pseudo-first-order model, pseudo-second-order model, Elovich model, and Webber-Morris intermolecular diffusion model. The sorption kinetics of the modeled ammonia waste were carried out using unmodified palm fibers and all kinds of surface modification. This process was best described by the pseudo-second-order sorption model, which can be considered as a confirmation of the chemical nature of ammonia sorption on raphia sp. fibers.

scholarly journals Fragmentation of Chitosan by Acids

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammad Reza Kasaai ◽  
Joseph Arul ◽  
Gérard Charlet
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Kinetic Data ◽  
Chemical Structure ◽  
Size Exclusion ◽  
Experimental Conditions ◽  
First Order ◽  
H Nmr ◽  
Exclusion Chromatography ◽  
Kinetics Of

Fragmentation of chitosan in aqueous solution by hydrochloric acid was investigated. The kinetics of fragmentation, the number of chain scissions, and polydispersity of the fragments were followed by viscometry and size exclusion chromatography. The chemical structure and the degree of N-acetylation (DA) of the original chitosan and its fragments were examined by1H NMR spectroscopy and elemental analysis. The kinetic data indicates that the reaction was of first order. The results of polydispersity and the DA suggest that the selected experimental conditions (temperature and concentration of acid) were appropriate to obtain the fragments having the polydispersity and the DA similar to or slightly different from those of the original one. A procedure to estimate molecular weight of fragments as well as the number of chain scissions of the fragments under the experimental conditions was also proposed.

Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Rate ◽  
Kinetic Isotope ◽  
Acid Base Equilibrium ◽  
Mineral Acids ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Ph Scale ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.

scholarly journals Biosorption and Diffusion Modeling of Pb(II) by Malt Bagasse

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Klaiani B. Fontana ◽  
Giane Gonçalves Lenzi ◽  
Erica R. L. R. Watanabe ◽  
Ervin Kaminski Lenzi ◽  
Juliana A. M. T. Pietrobelli ◽  
...  
Keyword(s):  
Sorption Process ◽  
Isotherm Models ◽  
Diffusion Modeling ◽  
Biosorption Capacity ◽  
Kinetic And Thermodynamic Parameters ◽  
Pseudo Second Order ◽  
Ph Optimization ◽  
Kinetics Of ◽  
And Diffusion

The removal of Pb(II) from water by biosorption processes onto malt bagasse was investigated and the kinetic and thermodynamic parameters were obtained; additionally a diffusion modeling was proposed. The characterization of malt bagasse was performed by FTIR and SEM/EDS. The experiments were conducted in batch system and an experimental design based response surface methodology was applied for agitation speed and pH optimization. The kinetics of biosorption followed pseudo-second-order model and the temperature of the process affected the biosorption capacity. Isotherm models of Langmuir, Freundlich, and Elovich were applied and the Langmuir model showed better fit and the estimated biosorption capacity was 29.1 mg g−1. The negative values obtained for ΔG° and positive values of ΔH° confirm, respectively, the spontaneous and endothermic nature of the process. The diffusion modeling was performed based on experiments in the absence of agitation to investigate the influence of the biosorbent on the sorption process of Pb(II) ions.

Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Veniamin Zheleznov ◽  
Aleksey Golikov ◽  
Tatiana Sokolnitskaya ◽  
Sergey Ivannikov
Keyword(s):  
Nanostructured Materials ◽  
Sorption Kinetics ◽  
Uranyl Ion ◽  
Competitive Sorption ◽  
Hydroxyl Groups ◽  
Complex Ions ◽  
The Stability ◽  
Kinetics Of ◽  
Mesoporous Structures ◽  
Ionic Forms

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

Sign in / Sign up

Export Citation Format

Share Document