The aims of this investigation were to estimate the kinetic rate and yield of iron dissolution as a function of pH from the Na-montmorillonite (SWy) clay mineral. Clay minerals, a crystal structure of aluminum silicates, represent the largest component of atmospheric aerosols, ~45 % of the total aerosol load. It is expected that these aerosols will dissolve into tropospheric (atmospheric) water, influencing the chemical balance of the atmosphere and other biogeochemical cycles, most importantly carbon. Mineral dust is one of the primary sources of iron for the ocean. This trace metal is important for phytoplankton growth, influencing the uptake of CO2 from the atmosphere thus changing the pH in ocean waters and in the troposphere.
This experiment incorporates mineral dust aerosols from the SWy clay mineral into an environmentally relevant and controlled aqueous reactor in order to study iron dissolution. Iron was analyzed through bulk dissolution experiments, which simulated the atmospheric conditions at which atmospheric particles are exposed before they are deposited into the ocean. The resulting soluble iron species – Fe2+, Fe3+ and total Fe – were quantified colorimetrically. To the best of our knowledge this is the first study of iron speciation dissolution from clay mineral aerosols as a function of pH.
Level of Honors
Juan G. Navea
Perez, Beatriz, "Iron Dissolution from Clay Mineral Aerosols in Acidic Media" (2013). Lawrence University Honors Projects. Paper 41.