Generalized solution to multi-dimensional multi-species transport equations coupled with a first-order reaction network involving distinct retardation factors

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

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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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Complete monotonicity of entropy production in chemical reaction

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810452 ◽

1981 ◽

Vol 46 (2) ◽

pp. 452-456

Author(s):

Milan Šolc

Keyword(s):

Entropy Production ◽

Equilibrium Constant ◽

Chemical Reaction ◽

Relative Entropy ◽

Order Reaction ◽

Complete Monotonicity ◽

First Order Reaction ◽

First Order ◽

Completely Monotonic ◽

Derivatives Of

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.

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