Single-Step Green Synthesis of Iron Nanoparticles in the Aqueous Phase for Catalytic Application in Degradation of Malachite Green

2021 ◽  
pp. 16-29
Author(s):  
Ajay Rathore ◽  
Vijay Devra
Keyword(s):  
Malachite Green ◽  
Iron Nanoparticles ◽  
Degradation Kinetics ◽  
Activation Parameters ◽  
Single Step ◽  
Oxidation Potential ◽  
Catalytic Application ◽  
First Order Kinetics ◽  
Optimum Reaction ◽  
Instrumental Approaches

The goal of the research was to devise a simple and environment-friendly approach to synthesize iron nanoparticles (FeNPs) and evaluate the catalytic activity of biosynthesized FeNPs for the degradation of the cationic dye Malachite Green (MG) in the presence of Peroxomonosulphate (PMS). Different instrumental approaches were used to characterize green produced FeNPs, and the results show that the NPs are spherical and 48 nm in size. Increasing the concentrations of nanoparticles (0.5 × 10-8 - 2.0 × 10-8 mol/dm3), Peroxomonosulphate (1.0 × 10-4 - 5.0 × 10-4 mol/dm3), dye (1.0 × 10-5 - 5.0 × 10-5 mol/dm3), pH (5), and high temperature (25-35 °C) enhanced the degradation kinetics of Pseudo-first-order kinetics were used to describe the degradation of MG in the FeNPs/PMS system, and activation parameters were derived. The maximum MG degrading efficiency for the FeNPs/PMS system was 88% in 60 minutes under optimum reaction conditions. The structure of intermediates formed by MG degradation by FeNPs/PMS was determined using UV-vis spectrum analysis. The application of synthesized FeNPs to improve Peroxomonosulphate oxidation potential for MG degradation is a unique, efficient, promising, and eco-friendly technology because it does not require any expensive reagents.  

scholarly journals KINETICS OF REACTION BETWEEN MALACHITE GREEN AND HYDROXYL ION IN THE PRESENCE OF REDUCING SUGARS

2015 ◽  
Vol 23 (23) ◽  
pp. 61-72
Author(s):  
Dayo Felix Latona ◽  
Adewumi Oluwasogo Dada
Keyword(s):  
Malachite Green ◽  
Activation Parameters ◽  
Cell Compartment ◽  
First Order ◽  
Rate Determining Step ◽  
First Order Kinetics ◽  
Hydroxyl Ion ◽  
Kinetics Of Reaction ◽  
Kinetics Of ◽  
Sphere Mechanism

The reaction was studied via pseudo-first-order kinetics using a UV-1800 Shimadzu spectrophotometer with a thermostated cell compartment and interfaced with a computer. The reaction showed first order with respect to malachite green and sugar and hydroxyl ion concentrations. However, the reaction was independent of ionic strength and showed no dependence on the salt effect, indicating an inner sphere mechanism for the reaction. There was no polymerization of the reaction mixture with acrylonitrile, indicating the absence of radicals in the course of the reaction. Michaelis-Menten plot indicated the presence of a reaction intermediate in the rate-determining step. The activation parameters of the reaction have been calculated and products were elucidated by FTIR spectroscopy. The stoichiometry of the reaction is 1:1. A mechanism consistent with the above facts has been suggested.

Kinetics and Mechanism of Oxidation of Aliphatic Secondary Alcohols by Benzimidazolium Fluorochromate in Dimethyl Sulphoxide Solvent

2021 ◽  
Vol 37 (3) ◽  
pp. 626-633
Author(s):  
Bhawana Arora ◽  
Jitendra Ojha ◽  
Pallavi Mishra
Keyword(s):  
Activation Parameters ◽  
Sigmatropic Rearrangement ◽  
Dimethyl Sulphoxide ◽  
Secondary Alcohols ◽  
Hydrogen Ions ◽  
Reaction Conditions ◽  
First Order Kinetics ◽  
Aqueous Solvent ◽  
Ester Formation ◽  
Different Temperatures

Oxidation of secondary alcohols is an important part of synthetic organic chemistry. Various studies are carried out at different reaction conditions to determine the best mechanistic pathways. In our study, oxidation of different secondary alcohols was done by using Benzimidazolium Fluorochromate in Dimethyl Sulphoxide, which is a non-aqueous solvent. Oxidation resulted in the formation of ketonic compounds. The reaction showed first order kinetics both in BIFC and in the alcohols. Hydrogen ions were used to catalyze the reaction. We selected four different temperatures to carry out our study. The correlation within the activation parameters like enthalpies and entropies was in accordance with the Exnerʼs criterion. The deuterated benzhydrol (PhCDOHPh) oxidation exhibited an important primary kinetic isotopic effect (kH / kD = 5.76) at 298 K. The solvent effect was studied using the multiparametric equations of Taft and Swain. There was no effect of addition of acrylonitrile on the oxidation rate. The mechanism involved sigmatropic rearrangement with the transfer of hydrogen ion taking place from alcohol to the oxidant via a cyclic chromate ester formation.

The kinetics and the mechanism of oxidative decarboxylation of benzilic acid by acidic permanganate (stopped-flow technique) — An autocatalytic study

2004 ◽  
Vol 82 (9) ◽  
pp. 1372-1380 ◽  
Author(s):  
Sairabanu A Farokhi ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Activation Parameters ◽  
Oxidative Decarboxylation ◽  
Two Stage ◽  
First Order ◽  
First Order Kinetics ◽  
Stage Process ◽  
Benzilic Acid ◽  
Reaction Constants ◽  
Kinetics Of ◽  
Good Agreement

The kinetics of the oxidation of benzilic acid by potassium permanganate in an acidic medium were studied spectrophotometrically. The reaction followed a two-stage process, wherein both stages of the reaction followed first-order kinetics with respect to permanganate ion and benzilic acid. The rate of the reaction increased with an increase in acid concentration. Autocatalysis was observed by one of the products, i.e., manganese(II). A composite mechanism involving autocatalysis has been proposed. The activation parameters of the reaction were calculated and discussed and the reaction constants involved in the mechanisms were calculated. There is a good agreement between the observed and calculated rate constants under different experimental conditions.Key words: oxidation, autocatalysis, benzilic acid, two-stage kinetics.

scholarly journals PERSISTENCIA DEL ENDOSULFÁN EN MEDIO ACUOSO ESTÁTICO

2001 ◽  
Vol 11 ◽  
Author(s):  
ARGELIA M. L. LENARDÓN ◽  
PATRICIA M. DE LA SIERRA ◽  
FERNANDA MARINO
Keyword(s):  
River Water ◽  
Degradation Kinetics ◽  
Water Type ◽  
Ultrapure Water ◽  
First Order ◽  
First Order Kinetics ◽  
Predominant Factor ◽  
Two Temperatures ◽  
In The Beginning ◽  
Kinetics Of

Estudou-se a cinética de degradação da mistura dos isômeros alfa e beta Endosulfan em diferentes condições de trabalho. Os compostos foram adicionados em água ultrapura, água do rio, água de rio filtrada e água ultrapura com sais (salinidade similar à agua do rio utilizada). As condições de degradação escolhidas foram: escuridão e duas temperaturas (14+1 ºC e 26+1 ºC). As amostragens foram programadas de modo a se obter dados periódicos mais freqüentes no início da experiência e posteriormente mais espaçados até o seu final (230 dias). As amostras foram submetidas à microextração e analisadas por cromatografia em fase gasosa com detector de Ni63 e coluna Megabore DB-5. A degradação foi descrita de acordo com a cinética de primeira ordem, determinando-se os tempos de meia vida (t1/2) e as energias de ativação (Ea). Os dados obtidos evidenciaram que a temperatura é o fator preponderante, sendo possível deduzir que o alfaendosulfan, exceto para água ultrapura (AU), é mais influenciado pela temperatura do que o beta-endosulfan. O segundo efeito mais importante refere-se ao tipo de água utilizada como matriz, devido à influência da salinidade. PERSISTANCE OF ENDOSULFAN IN STATIC AQUEOUS MEDIUM Abstract Degradation kinetics of a mixture of alpha- and beta-Endosulfan isomers was studied under different conditions. The compounds were spiked in ultrapure water, river water, filtered water and ultrapure water with salts (similar salinity condition to that of the river water used). The degradation conditions chosen were: darkness, two temperatures (14+1 ºC e 26+1 ºC). Samplings were programmed in order to obtain more frequent periodical data in the beginning of the experience and after more spaced until its end (230 days). The samples were submitted to microextraction and then analyzed by gas chromatography through a Ni63 detector equipped with a Megabore DB-5 column. Degradation was described using first-order kinetics to determine half-life times (t1/2) and activation energies (Ea). The data obtained evidenced that temperature is the predominant factor, it can possibly be inferred that alfa-endosulfan is much more influenced than beta-endosulfan except for ultrapure water (UW). The second important effect is the water type used as matrix, due to the influence of salinity.

The In Vitro Degradation Kinetics of Polyurethane Prodrug Materials

2011 ◽  
Vol 399-401 ◽  
pp. 1067-1070
Author(s):  
Chun Yan Li ◽  
Cong Cong Hu ◽  
Zhi Guo Wen ◽  
Sheng Xiong Dong
Keyword(s):  
Drug Release ◽  
High Performance ◽  
Degradation Kinetics ◽  
Hplc Method ◽  
In Vitro Degradation ◽  
Erosion Mechanism ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

The method of high performance liquid chromatography (HPLC) is established to determine the content of antibacterial agent — ciprofloxacin (CF) in the degradation solution of ciprofloxacin-polyurethane (CFPU) and investigate the in vitro degradation kinetics by plotting and fitting the cumulative release curves to inspect the effects of different medium and different concentrations on drug release. The results showed that the HPLC method is accurate, reliable and simple. The drug-release of CFPU was bioresponsive and could be accorded with first order kinetics. It was observed that CF was released from CFPU by a combination of diffusion and erosion mechanism, mainly in the manner of diffusion in the absence of infection while erosion mechanism in the presence of infection.

scholarly journals Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways

2018 ◽  
Vol 5 (2) ◽  
pp. 171372 ◽  
Author(s):  
Yuqing Tang ◽  
Xueting Shi ◽  
Yongze Liu ◽  
Li Feng ◽  
Liqiu Zhang
Keyword(s):  
Degradation Kinetics ◽  
Clofibric Acid ◽  
Basic Solution ◽  
Uv Photolysis ◽  
Chlorination Process ◽  
Chlorine Disinfection ◽  
First Order Kinetics ◽  
Disinfection Process ◽  
Acidic Conditions ◽  
Degradation Intermediates

As a potential endocrine disruptor, clofibric acid (CA) was investigated in this study for its degradation kinetics and pathways in UV/chlorine process. The results showed that CA in both UV photolysis and UV/chlorine processes could be degraded via pseudo-first-order kinetics, while it almost could not be degraded in the dark chlorination process. The observed rate constant ( k obs ) in UV photolysis was 0.0078 min −1, and increased to 0.0107 min −1 combining with 0.1 mM chlorine. The k obs increased to 0.0447 min −1 with further increasing the chlorine dosage from 0.1 to 1.0 mM, and reached a plateau at higher dosage (greater than 1.0 mM). The higher k obs was obtained at acid solution rather than basic solution. Moreover, the calculated contributions of radical species to k obs indicated that the HO• contributed significantly to CA degradation in acidic conditions, while the reactive chlorine species and UV direct photolysis dominated in neutral and basic solution. The degradation of CA was slightly inhibited in the presence of HC O 3 − (1 ∼ 50 mM), barely affected by the presence of Cl − (1 ∼ 200 mM) and greatly suppressed by humic acid (0 ∼ 5 mg l −1 ). Thirteen main degradation intermediates and three degradation pathways of CA were identified during UV/chlorine process.

Synthesis and Characterization of Green Tea Stabilized Iron Nanocatalysts for Brymothymol Blue (BTB) Degradation

2016 ◽  
Vol 42 ◽  
pp. 1-13
Author(s):  
David Mutuku Katithi ◽  
Immaculate N. Michira ◽  
Peterson M. Guto ◽  
Priscilla Gloria Lorraine Baker ◽  
Geoffrey N. Kamau ◽  
...  
Keyword(s):  
Green Tea ◽  
Dye Degradation ◽  
Degradation Kinetics ◽  
Environmental Pollutant ◽  
X Ray Diffraction ◽  
Tunneling Microscopy ◽  
X Ray ◽  
First Order Kinetics ◽  
Different Temperatures

Iron nanoparticles (FeNPs) were prepared from the green tea extracts at different temperatures through green synthesis procedure and characterized by various physicochemical techniques like UV-Visible spectroscopy, FTIR Spectroscopy, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and high resolution tunneling microscopy (HRTEM) and the results confirmed the synthesis of polydisperse and stable FeNPs by the tea extracts. The catalytic activity of FeNPs was investigated using a common environmental pollutant BTB often used in textile industries for dyeing purposes. In these tests, catalytic degradation of BTB with FeNPs at a 10 μL or 30 μL concentration was done in the presence of 2% hydrogen peroxide. Results show no BTB degradation in the absence of the FeNPs. However, a 38% and 68% degradation of BTB was realized in the presence of 10μL and 30 μL FeNPs respectively indicating that the iron nanocatalysts were responsible for the dye degradation. The BTB degradation kinetics was found to follow pseudo-first order kinetics with rate constants at the two catalyst concentrations being 0.023 min-1 and 0.063 min-1 respectively.

scholarly journals Kinetics of solvolysis in water of four secondary alkyl nitrates

1982 ◽  
Vol 60 (13) ◽  
pp. 1780-1785 ◽  
Author(s):  
Ross Elmore Robertson ◽  
Kalvelil Matthew Koshy ◽  
Adrianne Annessa ◽  
Jan N. Ong ◽  
John Marshall William Scott ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Rate Constant ◽  
Analytical Methods ◽  
Kinetic Data ◽  
Activation Parameters ◽  
Single Step ◽  
Alkyl Nitrates ◽  
Two Stage ◽  
Kinetics Of ◽  
Single Step Reaction

Kinetic data are reported for the solvolysis in water of propane-2-nitrate, butane-2-nitrate, cyclopentyl nitrate, and cyclohexyl nitrate. In each case, the dependence of rate constant on temperature is analysed in terms of two mechanisms for the solvolytic reaction. First it is assumed that the rate constant describes a single step reaction, the analysis leading to estimates of the heat capacity of activation ΔCp≠. Three different analytical methods are discussed in this regard. Second it is assumed that the rate constant describes a two stage mechanism, the first stage being reversible. In this case the explanation of the ΔCp≠ term calculated according to the first mechanism is quite different. We comment on the alternative explanations of trends in activation parameters.

scholarly journals Photocatalytic Degradation of Rhodamine B and Malachite Green by Cobalt Sulfide Nanoparticles

2022 ◽  
Vol 34 (2) ◽  
pp. 331-341
Author(s):  
Gunjan Chauhan ◽  
Manjeet Sharma
Keyword(s):  
Malachite Green ◽  
Rhodamine B ◽  
Degradation Rate ◽  
Uv Light ◽  
Average Particle Size ◽  
Single Step ◽  
Cobalt Sulfide ◽  
Cds Nanoparticles ◽  
Average Particle ◽  
Cobalt Sulphide

Present study reports the simple and cost effective thermolytic method for the synthesis of cobalt sulphide nanoparticles (CoS NPs). The PXRD spectrum of cobalt sulphide (CdS) nanoparticles exhibited four peaks indexed to (100), (101), (102) and (110) crystal planes. The average particle size observed from DLS and PXRD was in the range 4.81-12.20 nm. A blue shift in band gap was observed from UV-visible spectra. The FESEM and TEM studies revealed that cobalt sulfide nanoparticles are of cubic and rectangle shapes. FTIR spectra of hexadecylamine (HDA) capped CoS NPs exhibited ν(N-H) absorption around 3350-3240 cm–1. The stretching frequency due to ν(Co-S) appeared in the region 334-332 cm–1. Proton NMR (1H) spectra of CoS NPs showed signals at nearly same positions as in case of capping agent, suggesting its capping nature. ESI-MS analyses of cobalt sulphide nanoparticles displayed peak at m/z = 124.93 corresponding to the [CoS2]+ ion. Thermogravimetric curves showed single step decomposition corresponding to 84.28% weight loss and 15.72% as final residue due to cobalt oxide. The degradation rate of rhodamine B and malachite green dyes after irradiating with sunlight showed 92-94% degradation while irradiated with UV-light of 4.8 eV show much slower degradation rate.

Degradation of malachite green by a pulsed light/H2O2 process

2019 ◽  
Vol 79 (2) ◽  
pp. 260-269 ◽  
Author(s):  
Patricia Navarro ◽  
Jean Pier Zapata ◽  
Gemma Gotor ◽  
Rafael Gonzalez-Olmos ◽  
Vicente M. Gómez-López
Keyword(s):  
Light Source ◽  
Malachite Green ◽  
Hydroxyl Radicals ◽  
Degradation Rate ◽  
Dye Degradation ◽  
Degradation Pathway ◽  
Photochemical Reactions ◽  
Pulsed Light ◽  
Light Pulses ◽  
First Order Kinetics

Abstract Pulsed light (PL) is a type of photonic technology characterized by intense short light pulses that enhance the speed of photochemical reactions, and which might be useful as light source in advanced oxidation processes. This work aimed to test PL as light source for the degradation of the dye malachite green (MG) by combining PL with H2O2. To this end, the effect of dye and H2O2 concentrations and pH on the degradation rate of MG was studied and a degradation pathway was proposed. Dye degradation followed a pseudo-first order kinetics; it increased with low initial dye concentration, high H2O2 concentration and low pH. Complete decolourization was achieved after 35 light pulses (75 J/cm2), with a degradation rate of 0.0710 cm2/J. The degradation was initiated by the attack of hydroxyl radicals to the central carbon of MG generating 4-(dimethylamino)benzophenone (DLBP) followed by the addition of hydroxyl radicals to the non-amino aromatic ring of DLBP and the demethylation of the amino group. Results indicate that PL technology has potential to be implemented to decrease the environmental impact of dyeing industries.

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