scholarly journals Kinetics of aqueous extraction of phenolic compounds from processed yerba mate leaves

2021 ◽  
pp. 39-53
Author(s):  
Gabriela G. López ◽  
María M. Brousse ◽  
María L. Vergara ◽  
Adriana M. Gonzalez ◽  
Nancy E. Cruz ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Equilibrium Concentration ◽  
Extraction Process ◽  
Second Order ◽  
Aqueous Extraction ◽  
Percentage Error ◽  
Yerba Mate ◽  
Order Kinetic ◽  
Diffusive Model ◽  
Kinetics Of

In this study, the kinetics of aqueous extraction of phenolic compounds from the yerba mate leaves were analyzed. A temperature range between 40°C and 70°C and a ratio of 25 g of mate leaves in 200 mL of water were used. The extraction kinetic was studied adjustment of the kinetics models of first order, second order kinetic model and the second order diffusive model. The goodness of the fit was controlled by the magnitude of the coefficient of determination (R2), the percentage error (EP %) and the square root of the mean square error (RMSE).The second order kinetic models adequately described the extraction process, achieving the best fit with the second order diffusive model (EP%= 0,81 to 2,9; EP%= 11,24 to 14,99 and 4,72 and 6,92) that provided important information about the initial extraction process and the mechanism that occurs in the final extraction stage. The temperature influenced the kinetic parameters; however, the final equilibrium concentration of phenolic compounds was not affected by it. The results of this study allow us to obtain better overall knowledge of the times and temperatures for improved extraction rates and energy consumption for the industrialization of these compounds.

scholarly journals Kinetics of scandium recovery by TVEX-TBP from the solution formed after the salt chlorinator cake leaching

2020 ◽  
Vol 168 ◽  
pp. 00050
Author(s):  
Vadym Korovin ◽  
Yurii Pohorielov ◽  
Yurii Shestak ◽  
Oleksandr Valiaiev ◽  
Jose Luis Cortina
Keyword(s):  
Chemical Interaction ◽  
Extraction Process ◽  
Second Order ◽  
Order Kinetic ◽  
Order Model ◽  
Elovich Equation ◽  
Diffusion Phase ◽  
Leaching Solution ◽  
Pseudo Second Order ◽  
Kinetics Of

Kinetics of scandium recovery by TVEX containing tributyl phosphate was studied from the clarified leaching solution of salt chlorinator cake. To assess the contribution of each diffusion phase, experimental data were analyzed using a graphic method. To define the contribution of chemical interaction into the scandium extraction process, recovery kinetics was quantitatively described using pseudo-first order, pseudo-second order kinetic models and Elovich equation in linearized form. It was established that recovery kinetics was most accurately described with the pseudo-second-order model.

scholarly journals Kinetics of Phenolic Compounds Modification during Maize Flour Fermentation

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6702
Author(s):  
Oluwafemi Ayodeji Adebo ◽  
Ajibola Bamikole Oyedeji ◽  
Janet Adeyinka Adebiyi ◽  
Chiemela Enyinnaya Chinma ◽  
Samson Adeoye Oyeyinka ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Phenolic Acids ◽  
Kinetic Models ◽  
Titratable Acidity ◽  
Second Order ◽  
Soluble Solids ◽  
Maize Flour ◽  
First Order ◽  
Compound Modification ◽  
Kinetics Of

This study aimed to investigate the kinetics of phenolic compound modification during the fermentation of maize flour at different times. Maize was spontaneously fermented into sourdough at varying times (24, 48, 72, 96, and 120 h) and, at each point, the pH, titratable acidity (TTA), total soluble solids (TSS), phenolic compounds (flavonoids such as apigenin, kaempferol, luteolin, quercetin, and taxifolin) and phenolic acids (caffeic, gallic, ferulic, p-coumaric, sinapic, and vanillic acids) were investigated. Three kinetic models (zero-, first-, and second-order equations) were used to determine the kinetics of phenolic modification during the fermentation. Results obtained showed that fermentation significantly reduced pH, with a corresponding increase in TTA and TSS. All the investigated flavonoids were significantly reduced after fermentation, while phenolic acids gradually increased during fermentation. Among the kinetic models adopted, first-order (R2 = 0.45–0.96) and zero-order (R2 = 0.20–0.82) equations best described the time-dependent modifications of free and bound flavonoids, respectively. On the other hand, first-order (R2 = 0.46–0.69) and second-order (R2 = 0.005–0.28) equations were best suited to explain the degradation of bound and free phenolic acids, respectively. This study shows that the modification of phenolic compounds during fermentation is compound-specific and that their rates of change may be largely dependent on their forms of existence in the fermented products.

scholarly journals KINETICS OF OZONE REACTIONS WITH ADENINE AND CYTOSINE IN AQUEOUS SOLUTIONS

2020 ◽  
Vol 63 (10) ◽  
pp. 17-22
Author(s):  
Aigul A. Maksyutova ◽  
Elvina R. Khaynasova ◽  
Yuriy S. Zimin
Keyword(s):  
Aqueous Solutions ◽  
Rate Constants ◽  
Correlation Coefficients ◽  
Activation Parameters ◽  
Second Order ◽  
Order Kinetic ◽  
Temperature Dependences ◽  
Ozone Reactivity ◽  
Kinetics Of ◽  
Ozone Reactions

The ultraviolet spectroscopy method has been applied to study the kinetics of the ozone reactions with nitrogenous bases (NB), namely adenine and cytosine in aqueous solutions. At the first research stage, the range of NB working concentrations has been determined. It was found that linear dependences between optical densities and concentrations of nitrogenous bases aqueous solutions are quite reliable, with correlation coefficients r ≥ 0.998, are satisfied up to [NB] = 2.3 ∙ 10–4 mol/l. According to the Bouguer-Lambert-Beer law, adenine and cytosine extinction coefficients in aqueous solutions were determined and subsequently used to calculate their residual concentrations. At the next stage, the kinetics of nitrogenous bases ozonized oxidation was studied with equal initial concentrations of the starting substances ([NB]0 = [О3]0). The results revealed that the kinetic consumption curves of the starting reagents are fairly well linearized (r ≥ 0.996) in the second-order reaction equation coordinates. As found with the bubbling installation, 1 mol of the absorbed ozone falls on 1 mol of the used NB. Thus, the reactions of ozone with adenine and cytosine explicitly proceed according to the second-order kinetic laws (the first – according to О3 and the first – according to NB). The rate constants were calculated by the integral reaction equations, the values of which indicate a higher ozone reactivity in relation to nitrogen bases. The temperature dependences of the second-order rate constants was studied ranging 285-309 K, and the activation parameters (pre-exponential factors and activation energies) of the ozone reactions with adenine and cytosine in aqueous solutions were determined.

Adsorption Kinetics of Reactive Dyes on Silk with Octyl Butyl Dimethyl Ammonium Bromide as Accelerant

2012 ◽  
Vol 549 ◽  
pp. 278-282 ◽  
Author(s):  
Cheng Chen ◽  
Guang Xian Zhang ◽  
Feng Xiu Zhang ◽  
Hui Zheng
Keyword(s):  
Adsorption Kinetics ◽  
Dye Adsorption ◽  
Reactive Dyes ◽  
Second Order ◽  
Ammonium Bromide ◽  
Order Kinetic ◽  
Dye Uptake ◽  
Dimethyl Ammonium ◽  
Adsorption Rates ◽  
Kinetics Of

With octyl butyl dimethyl ammonium bromide (OBDAB) as accelerant, adsorption kinetics of dyeing silk with three reactive dyes was studied in this paper. As concentration of OBDAB increased, the dye-uptake rate increased. The highest dye-uptake rates of three reactive dyes could reach to 89.40%~98.98% and the concentration of OBDAB was only 6-8g/L. This showed OBDAB was an effective accelerant. Pseudo first- and second-order kinetic models were used to analyze the adsorption kinetic data. The experimental data were found to follow the second-order kinetic model. Meanwhile, the initial dye adsorption rates of reactive red dye B-3BF, reactive yellow dye B-4RFN and reactive orange dye B-2RLN increased as temperature increased, and the activation energy of them were found respectively to be 28.42,13.14,32.90 kJ/mol.The positive values of and obtained indicated that reactive dyes adsorption with OBDAB as accelerant was an endothermic process. The conclusion showed OBDAB was a potential accelerant.

scholarly journals Preliminary Study: Kinetics of Oil Extraction from Sandalwood by Microwave-assisted Hydrodistillation

2016 ◽  
Vol 15 (2) ◽  
pp. 62 ◽  
Author(s):  
Heri Septya Kusuma ◽  
Mahfud Mahfud
Keyword(s):  
Rate Constant ◽  
Extraction Process ◽  
Oil Extraction ◽  
Second Order ◽  
Extraction Rate ◽  
Coefficient Of Determination ◽  
Extraction Capacity ◽  
Microwave Assisted ◽  
Kinetics Of ◽  
Initial Extraction

Sandalwood and its oil, is one of the oldest known perfume materials and has a long history (more than 4000 years) of use as mentioned in Sanskrit manuscripts. Sandalwood oil plays an important role as an export commodity in many countries and its widely used in the food, perfumery and pharmaceuticals industries. The aim of this study is to know and verify the kinetics and mechanism of microwave-assisted hydrodistillation of sandalwood based on a second-order model. In this study, microwave-assisted hydrodistillation is used to extract essential oils from sandalwood. The extraction was carried out in ten extraction cycles of 15 min to 2.5 hours. The initial extraction rate, the extraction capacity and the second-order extraction rate constant were calculated using the model. Kinetics of oil extraction from sandalwood by microwave-assisted hydrodistillation proved that the extraction process was based on the second-order extraction model as the experimentally done in three different steps. The initial extraction rate, h, was 0.0232 g L-1 min-1, the extraction capacity, CS, was 0.6015 g L-1, the second-order extraction rate constant, k, was 0.0642 L g-1 min-1 and coefficient of determination, R2, was 0.9597.

Kinetics Study Using Solvent-Free Microwave Extraction of Essential Oil from Allium sativum L.

2020 ◽  
Vol 840 ◽  
pp. 186-192
Author(s):  
Yeni Variyana ◽  
Mahfud Mahfud
Keyword(s):  
Essential Oil ◽  
Allium Sativum ◽  
Extraction Process ◽  
Second Order ◽  
Solvent Free ◽  
Order Kinetic ◽  
Microwave Extraction ◽  
Order Model ◽  
First Order ◽  
Best Fit

Extraction of Allium sativum L. using Solvent-Free Microwave Extraction (SFME) without the addition of solvents in the process has been carried out. SFME is an alternative technique and method to produce essential oil and it has several advantages in terms of product quality. In this study, the essential oil was extracted from Allium sativum used extraction time from 10 to 90 min and microwave power in the range of 300-600 W. The result showed that SFME could produce the highest yield of 0.2636 g oil/100 g fresh garlic at 450 W and 90 min. In addition, the kinetic study of SFME model appears to be the best fit to explain with second-order than first-order model. It was proved by a good correlation between the experimental data and model achieved (R2>0.99) and (RMSE=0.0021). Based on the results obtained, second-order kinetic models could actually describe the kinetics model of extraction process from Allium sativum L. using SFME.

Experimental Investigation on Adsorptive Removal of Phenolic Compounds from Aqueous Solution by Cr-Bentonite

2010 ◽  
Vol 160-162 ◽  
pp. 163-170
Author(s):  
Hong Zheng ◽  
Yang Wang ◽  
Peng Liang ◽  
Hong Bin Qi
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Phenolic Compounds ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Synthetic Wastewater ◽  
Order Kinetic ◽  
Sorption Data ◽  
Adsorptive Removal ◽  
Pseudo Second Order

The ability of Cr-bentonite prepared using synthetic wastewater containing chromium was investigated for adsorptive removal of 4-aminophenol and 4-chlorophenol from aqueous solution in a batch system at 25 °C. The physic-chemical parameters including pH value of solution and contact time were studied. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of sorption. The equilibrium sorption data for 4-aminophenol and 4-chlorophenol were well fitted to Langmuir adsorption isotherm and the monolayer sorption capacity was found to be 26.53 and 23.81 mg/g at 25 °C, respectively. The sorption energy calculated from Dubinin-Redushkevich (D-R) isotherm are 8.31 and 8.20 kJ/mol for the uptake of 4-aminophenol and 4-chlorophenol respectively which indicates that both the sorption processes are chemical in nature. The kinetic data were analyzed using pseudo-first order, pseudo-second order kinetic equation and intraparticle diffusion model. The experimental data fit very well the pseudo-second order kinetic model. Intraparticle diffusion affects 4-aminophenol and 4-chlorophenol uptake. Sorption studies carried out using industrial wastewater samples containing phenolic compounds show that there is significant potential for Cr-bentonite as an adsorbent material for phenollic compounds removal from aqueous solutions.

scholarly journals Recombination of Poly(Acrylic Acid) Radicals in Acidic Aqueous Solutions: A Pulse Radiolysis Study

2021 ◽  
Vol 11 (21) ◽  
pp. 10142
Author(s):  
Małgorzata Matusiak ◽  
Sławomir Kadłubowski ◽  
Piotr Ulański
Keyword(s):  
Acrylic Acid ◽  
Aqueous Solutions ◽  
Ph Dependence ◽  
Polymer Concentration ◽  
Second Order ◽  
Order Kinetic ◽  
Initial Number ◽  
Linear Charge Density ◽  
Kinetics Of ◽  
Poly Acrylic Acid

Carbon-centered radicals have been randomly generated on the chains of poly(acrylic acid), PAA, the simplest synthetic anionic polyelectrolyte, by pulse-irradiating its dilute, oxygen-free aqueous solutions by 6 MeV electron beam. In some experiments, oligo(acrylic acid), OAA, and propionic acid, PA, were used as PAA models. Recombination kinetics of PAA radicals has been followed by fast spectrophotometry. A strong pH dependence of radical lifetime on pH, and thus on the linear charge density due to deprotonated carboxylate groups, has been confirmed, while a weaker amplitude of pH dependence was observed for OAA and PA. Decay kinetics of PAA radicals in the protonated state, at pH 2, have been studied in some detail. At moderate doses of ionizing radiation, resulting in a moderate average initial number of radicals per chain, ZR0, the decay can be satisfactorily described by a second-order kinetic model, but a somewhat better fit is obtained by using a dispersive kinetics approach. While for a constant polymer concentration the reciprocal half-lives are proportional to the initial radical concentrations, such a data series for different PAA concentrations do not overlap, indicating that the overall radical concentration is not the decisive factor controlling the kinetics. Arranging all data, in the form of second-order rate constants, as a function of the average initial number of radicals per chain allows one to obtain a common dependence. The latter seems to consist of two parts: a horizontal one at low ZR0 and another one of positive slope at higher ZR0. This is interpreted as two kinetic regimes where two distinct reactions dominate, intermolecular and intramolecular recombination, respectively. Comparison of the low ZR0 data with calculations based on the translational diffusion model indicate that the latter is not the rate-controlling process in intermolecular recombination of polymer radicals; segmental diffusion is the more likely candidate.

scholarly journals Potential Biosorbent Derived fromCalligonum polygonoidesfor Removal of Methylene Blue Dye from Aqueous Solution

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Asma Nasrullah ◽  
Hizbullah Khan ◽  
Amir Sada Khan ◽  
Zakaria Man ◽  
Nawshad Muhammad ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Particle Size ◽  
Second Order ◽  
Blue Dye ◽  
Order Kinetic ◽  
Particle Size Analyzer ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Kinetics Of

The ash ofC. polygonoides(locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R2) of 0.999. The study revealed thatC. polygonoidesash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution.

Kinetics of Monochloramine Decay in Model and Distribution System Waters

2011 ◽  
Vol 183-185 ◽  
pp. 834-838 ◽  
Author(s):  
Shao Gang Liu ◽  
Chen Feng Fan ◽  
Zhi Liang Zhu
Keyword(s):  
Decay Rate ◽  
Distribution System ◽  
Distribution Systems ◽  
Ph Value ◽  
Second Order ◽  
Order Kinetic ◽  
Nitrite Ion ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Kinetics Of

The model of second-order reaction kinetics has been used to stimulate the monochloramine decay in model and distribution system waters by nonlinear fit. Several factors were investigated, including pH, bromide, nitrite concentrations in this system. The results showed that pH value was an important factor on the monochloramine decay rate, especially when pH was below 7.0. Presence of bromide ions had different impact under experimental conditions However, when pH was above 7.60, 0.1 mg/L concentration of bromide affect hardly the decay rate of mononchloramine. The results demonstrated that the second-order kinetic model could fit well the experimental results of monochloramine decay reaction under the conditions of bromide, and nitrite ion. Finally, the work presented here validates and extends this model for use in distribution systems under realistic chloramination conditions.

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