About

Speciation mode

CHESS is a high-performance speciation model which can be used to evaluate the chemical state of static or semi-dynamic aquatic systems. These tools allow to simulate the speciation of complex, natural or industrial solutions including oxides, minerals, colloids, organics and gases.

JCHESS is a graphical front-end and helps to quickly visualize the predominant species of an element as a function of some variable quantity. The figure at our left shows the speciation of cadmium in presence of colloidal hydrous ferric oxide, as a function of pH. Graphs are created by the user interface JCHESS and can be adapted to fit most specific needs.

JCHESS allows to easily construct speciation diagrams, such as Pourbaix- or activity diagrams, solubility diagrams and Mosaic diagrams. Pourbaix diagrams are often used to quickly grab an idea of which species predominates at specific pH and Eh.

More generally, activity-activity diagrams provide an interpretation of a database for one or several species with imposed activities. The picture above shows the expected speciation of 0.1 mmolal of lead (Pb) as a function of pH and Eh, within the domain of H2O stability. the collored areas areas are mineral phases. Such a diagram or much more complex examples are obtained in a few clicks, as illustrated in one of the screenshots.

JCHESS is an easy-to-use and intuitive graphical interface for CHESS, written in Java in order to take advantage of the cross-platform compatibility of this programming language. JCHESS runs on most common (Java-enabled) platforms such as Windows 95/98/2000/NT, Linux and Solaris. Good news for Macintosh users: MacOS X finally includes a Java 2 interpreter, hence CHESS is available for MacOS as well (screenshots).