Evidence in support of first-order dissolution kinetics of calcite in seawater

AbstractThe kinetics of dissolution of Amazonian metakaolin in hydrochloric acid (HCl) was studied using the ‘Shrinking Core Model’ for spherical and ‘flat plate’ particles of constant size. The Amazonian kaolin was calcined at 700°C for 2 h. The calcined samples (metakaolins) were leached in an HCl solution with 5% excess at 70, 80 and 95 ± 3°C for 3 h. Samples were collected every 15 min and subjected to Al analysis by the EDTA titrimetric method. Experimental data showed that the spherical morphology produced a better fit with respect to the regression coefficients. The activation energy of the reaction was 90.6 kJ/mol. The chemical process is a first-order leaching reaction. The results of the present study are consistent with those from previous research on this topic, which used HCl with an excess of >90%.

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Comparison of different models for describing gypsum dissolution kinetics in different aqueous salt solutions

Soil Research ◽

10.1071/sr9900947 ◽

1990 ◽

Vol 28 (6) ◽

pp. 947 ◽

Cited By ~ 6

Author(s):

H Singh ◽

MS Bajwa

Keyword(s):

Dissolution Kinetics ◽

Sodium Adsorption Ratio ◽

Standard Errors ◽

Salt Solutions ◽

Order Model ◽

Gypsum Dissolution ◽

First Order ◽

Aqueous Salt Solutions ◽

Elovich Equation ◽

Kinetics Of

Gypsum dissolution as a function of time was measured in solutions having a sodium adsorption ratio (SAR) of 7.5, 14 and 27 (mmol(+) kg-1)1/2 and an electrical conductivity (EC) of 1 5 and 3.1 dS m-1. The amount of gypsum dissolved increased with increases in the SAR and EC values of the different equilibrating solutions. The rate of gypsum dissolution was higher initially but declined with increasing time of equilibration. Of the total amount of gypsum dissolved in 40 h, about 60-70% dissolution occurred during the first 5 min. Comparisons of coefficients of determination (r2) and standard errors of estimate indicated that, in addition to the most widely used linear form of the first-order model, other models such as the power function, empirical (modified from first-order) and the Elovich equation, can also be used to describe the kinetics of gypsum dissolution in aqueous solutions varying in SAR and EC.

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Dissolution kinetics of Amazonian metakaolin in nitric acid

Cerâmica ◽

10.1590/0366-69132018643692179 ◽

2018 ◽

Vol 64 (369) ◽

pp. 86-90 ◽

Cited By ~ 3

Author(s):

P. E. A. Lima ◽

R. S. Angélica ◽

R. F. Neves

Keyword(s):

Nitric Acid ◽

Flat Plate ◽

Acid Leaching ◽

Dissolution Kinetics ◽

Regression Coefficients ◽

First Order ◽

Constant Size ◽

Shrinking Core ◽

Leaching Reaction ◽

Kinetics Of

Abstract The kinetic study of Amazon metakaolin dissolution was performed with the application of the shrinking core model for spherical and ‘flat plate’ particles with constant size. The Amazon kaolin was calcinated at 700 ºC in order to produce metakaolin. This metakaolin was leached with 5% excess nitric acid at 70, 80 and 95±3 ºC for 3 h. Samples were collected every 15 min and subjected to aluminum analysis. The acid leaching was a chemically controlled process. The spherical morphology showed better fit than the flat plate particles when taking into account the regression coefficients. 91.58 kJ/mol of activation energy was found as well as an aluminum leaching reaction of the first order. The results found in this work using 5% excess acid and Amazon kaolin were consistent with previous research results using excess acid above 50% and standard kaolin.

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Growth and dissolution kinetics of tetragonal lysozyme

10.2514/6.1993-717 ◽

1993 ◽

Author(s):

L. MONACO ◽

F. ROSENBERGER

Keyword(s):

Dissolution Kinetics ◽

Kinetics Of

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Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

10.31221/osf.io/m9g7p ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Methyl Orange ◽

Solution Ph ◽

Vanadium Concentration ◽

Limiting Behavior ◽

First Order ◽

First Order Kinetics ◽

Ph Range ◽

Kinetic Pattern ◽

Triton X ◽

Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

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The Kinetics of Glucose Decomposition with Sulfate Reduction in the Anaerobic Fluidized Bed Reactor

Water Science & Technology ◽

10.2166/wst.1993.0092 ◽

1993 ◽

Vol 28 (2) ◽

pp. 135-144 ◽

Cited By ~ 3

Author(s):

S. Matsui ◽

R. Ikemoto Yamamoto ◽

Y. Tsuchiya ◽

B. Inanc

Keyword(s):

Sulfate Reduction ◽

Fluidized Bed ◽

Kinetic Equations ◽

Fluidized Bed Reactor ◽

Order Reaction ◽

First Order Reaction ◽

First Order ◽

Glucose Decomposition ◽

Reaction Equations ◽

Kinetics Of

Using a fluidized bed reactor, experiments on glucose decomposition with and without sulfate reduction were conducted. Glucose in the reactor was mainly decomposed into lactate and ethanol. Lactate was mainly decomposed into propionate and acetate, while ethanol was decomposed into propionate, acetate, and hydrogen. Sulfate reduction was not involved in the decomposition of glucose, lactate, and ethanol, but was related to propionate and acetate decomposition. The stepwise reactions were modeled using either a Monod expression or first order reaction kinetics in respect to the reactions. The coefficients of the kinetic equations were determined experimentally. The modified Monod and first order reaction equations were effective at predicting concentrations of glucose, lactate, ethanol, propionate, acetate, and sulfate along the beight of the reactor. With sulfate reduction, propionate was decomposed into acetate, while without sulfate reduction, accumulation of propionate was observed in the reactor. Sulfate reduction accelerated propionate conversion into acetate by decreasing the hydrogen concentration.

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Submerged upflow biotower operation and computer simulation

Water Science & Technology ◽

10.2166/wst.1994.0554 ◽

1994 ◽

Vol 30 (11) ◽

pp. 143-146

Author(s):

Ronald D. Neufeld ◽

Christopher A. Badali ◽

Dennis Powers ◽

Christopher Carson

Keyword(s):

Computer Simulation ◽

Benzoic Acid ◽

Computer Model ◽

Rate Constants ◽

Batch Mode ◽

Operational Conditions ◽

First Order ◽

Low Concentrations ◽

Biological Transformation ◽

Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

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Study of the kinetics of electrode processes by means of electrolysis with constant current. XI. Irreversible consecutive two-step reaction of first order

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19673987 ◽

1967 ◽

Vol 32 (11) ◽

pp. 3987-3997 ◽

Cited By ~ 4

Author(s):

O. Dračka

Keyword(s):

Constant Current ◽

First Order ◽

Electrode Processes ◽

Kinetics Of

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A general treatment for the kinetics of two consecutive irreversible first-order reactions. Determination of rate constants for the tin(II)-ion catalysed esterification of alkali metal carboxybenzenesulphonates with ethylene glycol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19781907 ◽

1978 ◽

Vol 43 (7) ◽

pp. 1907-1916 ◽

Cited By ~ 4

Author(s):

Lubomír Nondek ◽

Jaroslav Málek

Keyword(s):

Alkali Metal ◽

Ethylene Glycol ◽

Rate Constants ◽

General Treatment ◽

First Order ◽

Kinetics Of

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Iodoacetate inactivation of rape alcohol dehydrogenase

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19801601 ◽

1980 ◽

Vol 45 (5) ◽

pp. 1601-1607 ◽

Cited By ~ 1

Author(s):

Marie Stiborová ◽

Sylva Leblová

Keyword(s):

Alcohol Dehydrogenase ◽

Protein Molecule ◽

Sulfhydryl Groups ◽

Inactivation Rate ◽

First Order ◽

Ph Dependent ◽

Kinetics Of

Iodoacetate inactivates rape alcohol dehydrogenase (ADH, EC 1.1.1.1). The inactivation rate follows the kinetics of the first order, is pH-dependent, and decreases below pH 7.5. Besides irreversible alkylation of the sulfhydryl groups of the enzyme iodoacetate also forms a reversible complex with rape ADH. The coenzyme (NAD) and its analogs (ATP, ADP, AMP) competitively protect the enzyme against alkylation; o-phenanthroline also protects the enzyme against alkylation yet noncompetitively with respect to iodoacetate. Imidazole and o-phenanthroline compete with one another for binding to the protein molecule of rape ADH. Whereas o-phenanthroline decreases the inactivation rate imidazole increases the rate of iodoacetate inactivation.

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