GEOC 131 |
| Because of its toxicity at low concentrations, arsenic has received increasing worldwide attention. While considerable research has been achieved understanding the interaction of arsenic and iron oxides via adsorption, information on arsenic desorption is limited. In our studies, the adsorption and desorption of arsenate from magnetite nanoparticles were examined under controlled conditions, regarding adsorption kinetics, desorption kinetics, and the pH effect on adsorption and desorption. Arsenate adsorption decreased with increasing pH. The equilibrium pH is important to determine the maximum arsenic adsorption capacities. Arsenate desorption was irreversible when arsenate adsorption was conducted at pH 4 followed by desorption with arsenic-free electrolyte at pH 10. Increasing desorption time resulted in more arsenate desorption. Arsenate adsorption at a given pH (i.e., pH 4 and 10) increased up to 24 h; arsenate desorption slightly occurred over a longer period of time (i.e., 120 h). |
|
The Structure and Reactivity of Nanoparticles in the Environment
9:00 AM-12:00 PM, Thursday, 14 September 2006 Moscone Center -- Room 262, Oral
Sci-Mix
Division of Geochemistry |