Sorption of iron cyanide compounds onto clay minerals and manganese oxides

Cyanide is a carbon-nitrogen chemical unit that tends to react readily with many other chemical elements, producing a wide variety of cyanide complexes. Manufactured gas plant (MGP) wastes contain high concentrations of cyanide combined with iron compounds. At most MGP sites, the technique used to purify H₂S and HCN produced concentrations ranging from 500 to 1000 mL/cu m. Sorption characteristics of an iron cyanide complex, Prussian blue, were studied as a function of mineral types (kaolinite, montmorillonite, illite, birnessite, and cryptomelane) and pH (3.7-9.7). The sorption of Prussian blue onto clay increased as pH decreased. Illite had the highest sorption capacity among clay minerals at the same pH. However, no pH effect was observed on the sorption of iron cyanide to manganese oxides. Sorption of iron cyanide compounds was significantly affected by type of soil and pH. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).