Organisation of the Analytical, Stoichiometric, and Thermodynamic Information for water Chemistry Calculations

Földényi, Rita and Marton, Aurél (2015) Organisation of the Analytical, Stoichiometric, and Thermodynamic Information for water Chemistry Calculations. HUNGARIAN JOURNAL OF INDUSTRY AND CHEMISTRY, 43 (1). pp. 33-38. ISSN 0133-0276


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A common feature of the chemical processes of the hydrosphere and water treatment plants is that essentially the same types of chemical equilibrium reactions occur in both fields. These equilibria could be acid/base, complexation, redox, precipitation, and interfacial processes. Since these reactions may also occur in combination, the aqueous environments are unavoidably multispecies systems. Due to multiple equilibria, the state of aggregation, the state of oxidation, as well as the electric charge of the species may changedramatically. Calculation of the equilibrium concentration of the species is facilitated by the availability of analytical, stoichiometric, and thermodynamic information that are consistently organised into an ASTI matrix. The matrix makes it possible to apply a uniform algebraic treatment for all occurring equilibria even, if later on, further reactions have to be included in the chemical model. The use of the ASTI matrix enables us to set up the necessary mass balance equations and equilibrium relationships, which together form a non-linear system of equations (NLSE). The goal of our paper is to show that the use of the ASTI matrix approach in cooperation with the powerful engineering calculation software, MATHCAD14, results in fast and easy handling of the NLSE-s and, consequently, the calculations of speciation in aqueous systems. The paper demonstrates the method of application in three examples: the calculation of the pH dependence of the solubility of calcite in closed and open systems, the calculation of the pH and pε in a system where acid/base reactions, complexation equilibria, and redox equilibria occur, and a study of adsorption of lead ions on aluminium oxide.

Item Type: Article
Additional Information:
Uncontrolled Keywords: adsorption of lead; redox calculation; solubility of calcite; ASTI matrix method; multiple solution equilibria
Subjects: Q Science / természettudomány > QD Chemistry / kémia
T Technology / alkalmazott, műszaki tudományok > TD Environmental technology. Sanitary engineering / környezetvédelem, hulladékkezelés, egészségügyi mérnöki technika (ivóvízellátási és szennyvízkezelési technika)
Depositing User: MTMT SWORD
Date Deposited: 23 Jul 2015 05:54
Last Modified: 23 Jul 2015 05:54

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