Parameters Describing the Available Surface

According to Dzombak and Morel (1990) only one type of surface site is necessary to model the anion adsorption onto the surface of amorphous iron hydroxide. The input parameters specifying the availability of these sites are total amount of sites (moles/L), specific area (m /g) and mass (g/L). 

The site density for anion adsorption onto the amorphous iron hydroxide surface ranges mainly between 0.1 and 0.3 mol sites/mol Fe(goii(i) (see data collection of Dzombak and Morel, 1990). Dzombak and Morel used 0.2 mol sites/mol Fe(goiid) as an approximate value and assumed a specific area of 600 m /g when deriving the complexation constants from the collected experimental batch test data. 

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