scholarly journals Catalytic and antimicrobial properties of α-amylase immobilised on the surface of metal oxide nanoparticles

2020 ◽  
Author(s):  
Olga Długosz ◽  
Julia Matysik ◽  
Wiktoria Matyjasik ◽  
Marcin Banach
Keyword(s):  
Reaction Rate ◽  
Metal Oxide Nanoparticles ◽  
Antimicrobial Properties ◽  
Reaction Rate Constant ◽  
High Catalytic Activity ◽  
Zno Nanoparticle ◽  
Effective Parameters ◽  
Maximum Reaction Rate ◽  
Kinetics Of Adsorption ◽  
Equilibrium And Kinetics

Abstract New methods of obtaining products containing enzymes reduce the costs associated with obtaining them, increase the efficiency of processes and stabilize the created biocatalytic systems. In the study a catalytic system containing the enzyme α-amylase immobilized on ZnO nanoparticle and Fe3O4 nanoparticles was created. The efficiency of the processes was obtained with variables: concentrations of enzymes, temperatures and times, to define the best conditions for running the process, for which were determined equilibrium and kinetics of adsorption. The most effective parameters of α-amylase immobilization on metal oxides were determined, obtaining 100.8 mg/g sorption capacity for ZnO and 102.9 mg/g for Fe3O4 nanoparticles. Base on the best parameters, ZnO-α-amylase was investigated as an antimicrobial agent and Fe3O4-α-amylase was tested as a catalyst in the process of starch hydrolysis. As a result of the conducted experiments, it was found that α-amylase immobilized on Fe3O4 nanoparticles maintained high catalytic activity (the reaction rate constant KM = 0.7799 [g/dm3] and the maximum reaction rate Vmax = 8.660 [g/(dm3min)]).

Basic Studies on Anaerobic Degradation of Glucose in Continuous Stirred Tank Reactors

1991 ◽  
Vol 24 (5) ◽  
pp. 141-147
Author(s):  
Michimasa Nakamura ◽  
Atsushi Sakai ◽  
Jun'ichiro Matsumoto
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acid ◽  
Reaction Rate ◽  
Ph Value ◽  
Reaction Rate Constant ◽  
The Other ◽  
Total Volatile ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Total Volatile Fatty Acid

The two series of the characteristics of anaerobic degradation of low glucose concentrations were investigated. In the first series, the pH value in each reactor was not controlled. In the second series, the pH value in each reactor was controlled in the range of 6.9–7.2, by adding sodium bicarbonate into each influent. The ORP value was depressed by controlling the pH value of each reactor from acid range to approximately neutral range. In the pH uncontrolled series, the pH value in outflow decreased with increasing glucose concentration. In the pH uncontrolled series, produced total volatile fatty acid was about 70 to 550 mg/l; on the other hand, in pH controlled series, produced total volatile fatty acid was about 50 mg/l to 350 mg/l. The highest concentrations of acids formed were acetic acids, the second highest formed were propionic acids, the last formed were butyric acids. In the pH uncontrolled series, the maximum reaction rate constant Vm was 0.749 gCOD/gVS · day and the saturation constant Ks = 0.435 g/l. On the other hand, in the pH controlled series, the maximum reaction rate constant Vm was 1.441 gCOD/gVS · day and the saturation constant Ks = 0.739 g/l. Thus by controlling the pH value of the reactor, the activities of the anaerobic bacteria were much enhanced.

Solid Phase Synthesis of S-Doped TiO2 Nanomaterials with Visible Light Degradation Property

2012 ◽  
Vol 509 ◽  
pp. 65-73 ◽  
Author(s):  
Ya Li Gao ◽  
Shao You Liu ◽  
Fei Zhang ◽  
Qing Ge Feng
Keyword(s):  
Visible Light ◽  
Reaction Rate ◽  
Ph Value ◽  
Solid Phase ◽  
Reaction Rate Constant ◽  
Pure Tio2 ◽  
High Catalytic Activity ◽  
Pseudo First Order Reaction ◽  
Tio2 Nanomaterials ◽  
Visible Light Degradation

S-doped TiO2 nanomaterials (S-TiO2) synthesized by solid state and liquid state reaction route were used for the visible light degradation of Rhodamine B. The results show that at 20°C，pH=5, the rule of pseudo-first-order reaction and high catalytic activity were found in the visible light degradation of RhB on the S-TiO2 nanomaterials and pure TiO2. Within 80 min, the visible light degradation ratio of RhB is 97.9%, which is 6.6 times for pure TiO2. The reaction conditions such as the initial concentration, pH value, the sorts of metal ions, and consumption of catalyst affect the reaction rate constant of S-TiO2 material. The addition of Cu2+ enhances the visible light degradation rate of 28.6%, but Cr3+ decreases greatly the reaction rate of RhB.

scholarly journals THE KINETICS OF SELECTIVE HYDRAZINOLYSIS OF MALEIC ACID ON THE ACID CATALYST

2021 ◽  
Vol 2 (446) ◽  
pp. 53-57
Author(s):  
S.A. Dzhumadullaeva ◽  
A.B. Bayeshov ◽  
A.V. Kolesnikov
Keyword(s):  
Hydrazine Hydrate ◽  
Maleic Acid ◽  
Reaction Rate ◽  
Cation Exchanger ◽  
Maleic Hydrazide ◽  
Acid Catalyst ◽  
Reaction Rate Constant ◽  
High Catalytic Activity ◽  
Static System ◽  
Probable Reaction

For the first time, kinetics and the mechanism of the reaction of hydrazinolysis of maleic acid in the presence of cation exchanger resin KU-2-8 in H-form have been studied. The experiments were carried out in a static system in a thermostat glass reactor. It was found that cation exchanger shows high catalytic activity in the studied process - maleic acid conversion was 93%, and maleic hydrazide yield was 90%. The conversion selectivity of maleic acid to maleic hydrazide was 97,8%. The reaction rate was determined from the accumulation of maleic hydrazide. The apparent reaction rate constant (k) was calculated from the second-order reaction rate equation. The effect of initial concentrations of maleic acid and hydrazine hydrate, the temperature on the reaction rate was studied. The first order of maleic acid and hydrazine hydrate is determined. Activation energy of the process found from the Arrhenius dependence is 32,1 kJ/mol. On the basis of kinetic and IR spectroscopic methods, a probable reaction mechanism involving polymer-bound hydrogen ions is proposed.

scholarly journals Determination of exothermic batch reactor specific model parameters

2019 ◽  
Vol 292 ◽  
pp. 01063
Author(s):  
Lubomír Macků
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Specific Model ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Model Parameters ◽  
Reactor Model ◽  
First Order

An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.

Performance of Photocatalytic Microfiltration with Hollow Fiber Membrane

2007 ◽  
Vol 544-545 ◽  
pp. 95-98 ◽  
Author(s):  
Jong Tae Jung ◽  
Jong Oh Kim ◽  
Won Youl Choi
Keyword(s):  
Heavy Metals ◽  
Humic Acid ◽  
Rate Constant ◽  
Hollow Fiber ◽  
Reaction Rate ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Reaction Rate Constant ◽  
Operational Parameters ◽  
Tio2 Particles

The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.

Reaction rate constant of SO3+ NH3in the gas phase

1990 ◽  
Vol 95 (D9) ◽  
pp. 13981 ◽  
Author(s):  
Gaunlin Shen ◽  
Masako Suto ◽  
L. C. Lee
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant

Photocatalytic Degradation of Methyl Orange by TiO2/Schorl Photocatalyst: Kinetics and Thermodynamics

2015 ◽  
Vol 713-715 ◽  
pp. 2789-2792
Author(s):  
Huan Yan Xu ◽  
Xue Li ◽  
Yan Li ◽  
Ping Li ◽  
Wei Chao Liu
Keyword(s):  
Methyl Orange ◽  
Reaction Rate ◽  
Reaction Kinetic ◽  
Kinetic Studies ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Solution Ph ◽  
Kinetics And Thermodynamics ◽  
Hoff Equation ◽  
Degradation Of Methyl Orange

An active dye, Methyl Orange (MO) was employed as the target pollutant to evaluate the photocatalytic activity of TiO2/schorl composite and the kinetics and thermodynamics of this process was emphasized in this work. Langmuir–Hinshelwood kinetic model was employed for the kinetic studies and the results revealed that the process of MO photocatalytic discoloration by TiO2/schorl composite followed one order reaction kinetic equation under different conditions. The reaction rate constant (k) increased with initial MO concentration decreasing. When the catalyst dosage or solution pH increased,kvalues increased and then decreased. The possible reasons for these phenomena were discussed. Finally, the thermodynamic parameters ΔG, ΔH, ΔSwere obtained by the classical Van't Hoff equation.

Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

2021 ◽  
Vol 21 (4) ◽  
pp. 2563-2567
Author(s):  
Nguyen Hoang Viet ◽  
Pham Ngoc Dieu Quynh ◽  
Nguyen Thi Hoang Oanh
Keyword(s):  
Reaction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Reaction Rate Constant ◽  
Reduction Degree ◽  
Furnace Temperature ◽  
Time Duration ◽  
Mill Scale ◽  
Fine Coal ◽  
Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

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