Kinetics of metribuzin degradation by colloidal manganese dioxide in absence and presence of surfactants

2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Qamruzzaman ◽  
Abu Nasar
Keyword(s):  
Sodium Dodecyl ◽  
Oxidative Degradation ◽  
Activation Parameters ◽  
Water Soluble ◽  
Ionic Surfactant ◽  
Ammonium Bromide ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Colloidal Mno2 ◽  
Kinetics Of

AbstractThe kinetics of the degradation of metribuzin by water-soluble colloidal MnO2 in acidic medium (HClO4) were studied spectrophotometrically in the absence and presence of surfactants. The experiments were performed under pseudo-first-order reaction conditions in respect of MnO2. The degradation was observed to be of the first order in respect of MnO2 while of fractional order for both metribuzin and HClO4. The rate constant for the degradation of metribuzin was observed to decrease as the concentration of MnO2 increased. The anionic surfactant, sodium dodecyl sulphate (SDS), was observed to be ineffective whereas the non-ionic surfactant, Triton X-100 (TX-100), accelerated the reaction rate. However, the cationic surfactant, cetyltrimethyl ammonium bromide (CTAB), caused flocculation with oppositely-charged colloidal MnO2; hence further study was not possible. The catalytic effect of TX-100 was discussed in the light of the available mathematical model. The kinetic data were exploited to generate the various activation parameters for the oxidative degradation of metribuzin by colloidal MnO2 in the absence as well as the presence of the non-ionic surfactant, TX-100.

Oxidative Degradation and Kinetics of Trichloroethylene by Thermally Activated Persulfate

2014 ◽  
Vol 675-677 ◽  
pp. 547-550
Author(s):  
Jun Jie Yue ◽  
Xiao Qiao Zhu ◽  
Yu Ting Wang ◽  
Yu Qin Zhang ◽  
Li Zhao ◽  
...  
Keyword(s):  
Oxidative Degradation ◽  
Chemical Oxidation ◽  
Molar Ratio ◽  
Pseudo First Order Reaction ◽  
In Situ Chemical Oxidation ◽  
First Order ◽  
Molar Ratios ◽  
Thermally Activated ◽  
Kinetics Of

In situ chemical oxidation with persulfate (PS) anion (S2O82-) is a viable technique for remediation of groundwater contaminants such as trichloroethylene (TCE). This laboratory study investigated the use of the oxidant sodium PS for the chemical oxidation of TCE at different conditions to determine the influence of temperature, pH, and the PS/TCE molar ratio. Experiments revealed that higher temperatures, lower pH, and higher PS/TCE molar ratios were to the benefit of TCE oxidation by PS. By investigating the reaction kinetics, the degradations of contaminant can be described by use of pseudo-first-order reaction. At the temperatures ranging from 25°C to 40°C, the activation energy for the degradation of TCE was determined to be 85.04 KJ/mol.

scholarly journals Kinetics of Micellar Effect of Non-Ionic Surfactant on Oxidative Degradation of Ciprofloxacin

2019 ◽  
Vol 32 (2) ◽  
pp. 359-368
Author(s):  
Ajaya Kumar Singh ◽  
Alpa Shrivastava ◽  
Dilip R. Shrivastava ◽  
Rajmani Patel ◽  
Neerja Sachdev
Keyword(s):  
Degradation Kinetics ◽  
Oxidative Degradation ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Degradation Process ◽  
Oxidation Products ◽  
Ionic Surfactant ◽  
Reaction Conditions ◽  
Chloramine T ◽  
Kinetics Of

Oxidative degradation kinetics of leading fluoroquinolone family drug ciprofloxacin (CIP) by chloramine-T (CAT) in TX-100 micelle media was studied spectrophotometrically at 275 nm and 298 K. In pseudo-first-order conditions the rate constant (kobs) decreased regularly with increasing [TX-100]. To understand the self-organizing activities of TX-100, CMC values in varying reaction conditions had been evaluated. The role of non-ionic surfactant in the oxidative degradation process of ciprofloxacin by chlorinating agent chloramine-T is explained in terms of mathematical model explained by Menger-Portnoy. The reaction showed first to zero order dependence on [CAT] and fractional order on [CIP]. Increasing [H+] decreased the rate of reaction. The effect of ionic strength and solvent polarity of the medium in reaction conditions were studied. The effects of added salts [HSO4Na], [KCl], [KNO3] and [K2SO4] had also been studied. The stoichiometry of the reaction determined was 1:2 and the oxidation products were identified by LC-EI-MS. The analysis of degradation product of ciprofloxacin evidently reveals that the piperazine moiety is active site for oxidation in the reaction. Activation parameters were studied to propose appropriate mechanism for the reaction.

A sensitive fluorescence method for monitoring the kinetics of microemulsion polymerization

2010 ◽  
Vol 88 (3) ◽  
pp. 185-191 ◽  
Author(s):  
Haike Feng ◽  
Yi Dan ◽  
Yue Zhao
Keyword(s):  
Induction Period ◽  
Sodium Dodecyl ◽  
Fluorescence Emission ◽  
Fluorescence Method ◽  
Water Soluble ◽  
Polymerization Process ◽  
Ionic Surfactant ◽  
Microemulsion Polymerization ◽  
Measurement Results ◽  
Kinetics Of

We present a fluorescence method that allows one to monitor the kinetics of microemulsion polymerization of very low monomer contents (water-to-monomer ratio can readily be superior to 1000). The microemulsion polymerization of methyl methacrylate (MMA) was investigated using N-(2-anthracene)methacrylamide (AnMA) as the probe whose fluorescence emission intensity was proportional to the conversion of MMA into the polymer. The real-time-measurement results show that in the regime of very low monomer contents, the surfactant exerted a profound effect on the kinetic process. In a microemulsion containing 0.1 wt% of MMA with respect to water, with the anionic surfactant of sodium dodecyl sulfate (SDS), the fast polymerization was preceded by an induction period whose length increased with reducing the concentration of the water-soluble initiator of potassium persulfate (KPS). By contrast, with the non-ionic surfactant of polyoxyethylene (20) oleyl ether (Brij98), the induction period was short and the decrease in the KPS concentration mainly resulted in a decrease of the reaction rate. The unprecedented sensitivity of this fluorescence method made it possible to access kinetic data of microemulsion polymerization with very low monomer contents for the first time, providing new insight into the effects of surfactant and initiator on this heterophase polymerization process.

Metallomicellar Hydrolytic Catalysts Containing Ligand Surfactants Derived from Alkyl Pyridin-2-yl Ketoxime

1997 ◽  
Vol 62 (8) ◽  
pp. 1342-1354 ◽  
Author(s):  
Radek Cibulka ◽  
David Dvořák ◽  
František Hampl ◽  
František Liška
Keyword(s):  
Metal Ion ◽  
Transition Metal Ions ◽  
Water Soluble ◽  
Hexadecyltrimethylammonium Bromide ◽  
Pseudo First Order Reaction ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
First Order ◽  
Substrate Cleavage ◽  
Kinetics Of

N-Hexyl- (2a), N-octyl- (2b), N-decyl- (2c) and N-dodecyl-N-[2-(hydroxyimino)-2-(pyridin-2-yl)ethyl]dimethylammonium (2d) nitrates were synthesized as water-soluble cationic ligand surfactants. Three types of micellar catalytic systems employing salts 2 were prepared: homomicellar water solutions of salts 2, comicellar solutions of salts 2 with an inert cationic tenside hexadecyltrimethylammonium bromide (CTAB) and comicellar systems consisting of complexes of ligand surfactants 2 with transition metal ions (Co(II), Ni(II), Cu(II) and Zn(II)) and CTAB. Hydrolytic efficiency of all micellar and metallomicellar systems was tested by measuring the kinetics of the model substrate cleavage under pseudo-first-order reaction conditions. Of the above-mentioned catalysts, comicellar systems of salts 2 comicellized with CTAB were most efficient. In all cases, with the exception of Zn(II), coordination of a metal ion decreased the hydrolytic efficiency of salts 2.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

scholarly journals Oxidative degradation of gentamicin present in water by an electro-Fenton process and biodegradability improvement

2019 ◽  
Vol 17 (1) ◽  
pp. 1017-1025
Author(s):  
Mohamed Réda Arhoutane ◽  
Muna Shueai Yahya ◽  
Miloud El Karbane ◽  
Kacem El Kacemi
Keyword(s):  
Chemical Oxygen Demand ◽  
Biological Process ◽  
Oxidative Degradation ◽  
Oxygen Demand ◽  
Polluted Water ◽  
Applied Current ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Appropriate Treatment ◽  
By Products

AbstractIn the context of environmental protection, where there is a need to develop effective operations for carrying out appropriate treatment of polluted water by pharmaceuticals. Therefore, the present study aims at evaluating the degradation for gentamicin through electro-Fenton (EF) operation, through taking into consideration the effect of several parameters of experimental in the process, namely, the concentration of initial gentamicin, the applied current and the Fe+2 (II) quantities. The (EF) operation employed involves a carbon-felt as cathode and platinum as anode at pH 3. Studies for the gentamicin kinetics is monitored by HPLC giving a pseudo-first order reaction following by a chemical oxygen demand, with a reached degree of mineralization 96% after of four hours of treatment through current 100 mA/cm2 with 0.1 mM of Fe+2. We find that the degradation for molecule of gentamicin is accompanied by an augmentation of the biodegradability, assesse through the Biochemical Oxygen Demand (BOD5) on chemical oxygen demand (COD) ratio, that augmentation from 0 to 0.41 before treatment after 30 min for EF treatment, showing that there is potential for conjugation of the EF process and the biological process. Furthermore, the by-products have been identified on the basis of HPLC-MS/MS results.

Mobility of DR1 Molecules Embedded in Nanostructured PMMA Films

2009 ◽  
Vol 5 ◽  
pp. 135-142
Author(s):  
Jorge A. García-Macedo ◽  
A. Franco ◽  
Guadalupe Valverde-Aguilar ◽  
M.A. Ríos-Enríquez
Keyword(s):  
Second Harmonic ◽  
Sodium Dodecyl ◽  
Orientation Distribution ◽  
Decay Rates ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Poling Field ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Kinetics Of

The kinetics of the orientation of Disperse Red 1 (DR1) molecules embedded in nanostructured Polymethylmetacrylate (PMMA) films was studied under the effect of an intense constant electric poling field. The changes in the orientation distribution of the DR1 molecules were followed by Second Harmonic Generation (SHG) measurements. The SHG signal was recorded as function of time at three different temperatures. We focused on both, the signal increases under the presence of the poling field and the signal decays without the poling field. The studied PMMA films were nanostructured by the incorporation of ionic surfactants as the Sodium Dodecyl Sulfate (SDS) and the Cetyl Trimethyl Ammonium Bromide (CTAB) during their preparation. The kinds of nanostructures obtained in the films were determined by means of X-ray diffraction (XRD) measurements. Substantial differences in signal intensity and in growth and decay rates between amorphous and nanostructured films were found.

scholarly journals Reactivity of Phenol and Aniline towards Quinolinium Chloro Chromate: A Comparative Oxidation Kinetic Study

2015 ◽  
Vol 59 ◽  
pp. 81-92
Author(s):  
Seplapatty Kalimuthu Periyasamy ◽  
H. Satham Hussain ◽  
R. Manikandan
Keyword(s):  
Oxidation Kinetic ◽  
Activation Parameters ◽  
Dipole Interaction ◽  
Reaction Rates ◽  
Hydrogen Ion ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
First Order ◽  
Different Temperatures ◽  
Kinetics Of

The kinetics of Oxidation of Phenol and aniline by quinolinium Chlorochromate (QCC) in aqueous acetic acid medium leads to the formation of quinone and azobenzene respectively. The reactions are first order with respect to both Phenol and aniline. The reaction is first order with respect to quinolinium chlorochromate (QCC) and is catalyzed by hydrogen ion. The hydrogen-ion dependence has the form: kobs = a+b [H+]. The rate of oxidation decreases with increasing dielectric constant of solvent, indicating the presence of an ion-dipole interaction. The reaction does not induced the polymerization of acrylonitrile. The retardation of the rate by the addition of Mn2+ ions confirms that a two electron transfer process is involved in the reaction. The reaction rates have been determined at different temperatures and the activation parameters have been calculated. From the above observations kinetic results a probable mechanism have been proposed.

scholarly journals Notizen: Kinetics of the Oxidation of Acetaldehyde by Manganese(III) Sulphate

1974 ◽  
Vol 29 (9-10) ◽  
pp. 691-693 ◽  
Author(s):  
M. S. Murdia ◽  
R. Shanker ◽  
G. V. Bakore
Keyword(s):  
Activation Parameters ◽  
First Order ◽  
Kinetics Of ◽  
Direct Attack

Oxidation of acetaldehyde with manganese(III)- sulphate is first order with respect to acetaldehyde and the oxidant. The rate is independent of acidity (2.0 > [H+] < 5.0 ᴍ and initial [Mn(II)]. Formaldehyde is one of the products of oxidation. Activation parameters for the reaction have been evaluated. The rate of enolisation under similar conditions is less than the rate of oxidation. A mechanism involving a direct attack on the aldehyde by Mn(III) has been suggested.

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