Specific Sorption Database

As to the knowledge of the author, there is no digital thermodynamic database for surface complexation equilibria existing world-wide, despite the vast amount of available data. This induces several severe drawbacks  

Therefore, a prototype of a digitized version of a thermodynamic sorption database has been implemented as a relational database with MS Access RES T -Rossendorf Expert System for Surface and Sorption Thermodynamics . It is mineral-specific and can therefore also be used for additive models of more complex solid phases such as rocks or soils. An integrated user interface helps users to access selected mineral and sorption data, to extract internally consistent data sets for sorption modelling, and to export them into formats suitable for other modelling software. 

For any value the used experimental method is stored, together with the respective ionic strength, the background media, and other information necessary to evaluate the data or derive other values. If published, errors for numerical data are included as a prerequisite for sensitivity and uncertainty analysis. 

In addition to such hard data items an extensive bibliography is provided with both original citations and secondary literature references. The cited literature comprises also model evaluations with respect to theoretical limitations, thermodynamic consistency and parameter sensitivity. Moreover, it covers questions of experimental methods (design, error ranges and application areas) and interpretation of results from sorption experiments. All this means a transition from a pure data collection towards a smart database, that finally will turn into a sorption expert system. This is supported by a broad variety of offered user interactions  

As of April 2002, the database contains 355 specific surface area values, 489 surface site property data sets, and 1168 records for surface complexation reactions for a total of 77 solid phases. 

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Brendler, V., Richter, A., Nebelung, C., and Vahle, A. (2004). Development of a Mineral-Specific Sorption Database for Surface Complexation Modeling. Part I, Final Report. Part n. Manual, Project PtWt+E 02E9471, EZ Rossendorf, Dresden, Germany. 

The paper summarizes eiforts started to deliver a profound chemical base for risk assessment, namely to properly take into account the physico-chemical phenomena governing the contamination source term development in time and space. One major aspect there is the substitution of conventional distribution coefficients (IQ values) for the empirical description of sorption processes by surface complexation models, in combination with other thermodynamic concepts. Thus, the framework of a Smart Kd is developed for complex scenarios with a detailed explanation of the underl3dng assumptions and theories. It helps to identify essential processes and the associated most critical parameters, easing further refinement studies. The presented case studies cover a broad spectrum of contamination cases and successfully demonstrate the applicability of the methodology. The necessity to create a mineral-specific sorption database to support the Smart IQ approach is derived and a first prototype for such a digital database introduced, combining numeric data with a knowledge base about the relevant theories, experimental methods, and structural information. 

The approach of research institutes AGLARG [9] was used for an operative estimation of gas sorption capacity for carbon sorbents. According to it micropore volume and the specific surface area have been chosen as determining parameters. To obtain the function approximating dependence of hydrogen sorption capacity on carbon materials from value of a specific surface area (at pressure 0.1 MPa and temperature 77 K), we used our experimental data (Table 1) and an experimental database (Table 2) of group of institutes - Inorganic Chemistry and Catalysis, Debye Institute, Utrecht University [10],... 

The Rossendorf expert system for surface and sorption thermodynamics, RES T (Brendler et al., 2003, 2004), is a mineral-specific digitized thermodynamic database that contains mineral properties, specific surface areas, ion sorption data, surface complexation reactions, and bibliographic information based... 

Generation of a database of GCMC sorption isotherms with respect to a specific adsorbate for a set of pore widths, pressures and temperatures. 

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