Complexation between Cr6+ and surface functional group

[ili]

Hello everyone!!

I am a beginner phreeqc user. Currently, I am working on adsorption of Cr6+ using agricultural waste. I would like to know the possibility of complexation reaction between Cr6+ and surface functional group in agricultural waste such as carboxylic acid. Is it possible to use phreeqc? Which database should I use? Any suggestion? 

[dlparkhurst]

Minteq.dat and minteq.v4.dat have data for aqueous complexation of Cr with various organic ligands (SOLUTION_MASTER_SPECIES and SOLUTION_SPECIES definitions). So these databases could give some guidance for aqueous Cr-ligand aqueous complexation.

However, all of the surface complexation definitions (SURFACE_MASTER_SPECIES and SURFACE_SPECIES) for all of the databases are related to hydrous ferric oxides (Hfo). So you would need to develop an entire surface complexation model for your agricultural medium.

[Charlie]

This may be helpful to you:

http://phreeqcusers.org/index.php/topic,358.0.html