The variability in iron speciation in size fractionated residual oil fly ash particulate matter (ROFA PM).

Ambient particulate matter (PM) containing iron can catalyze Fenton reaction leading to the production of reactive oxygen species in cells. It can also catalyze atmospheric redox reaction. These reactions are governed by the physicochemical characteristics of iron in ambient PM.

On the removal of hexavalent chromium from a Class F fly ash.

Coarse and fine samples of a Class F fly ash obtained from commercial combustion of Illinois bituminous coal have been exposed to two long-term leaching tests designed to simulate conditions in waste impoundments. ICP-AES analysis indicated that the coarse and fine fly ash samples contained 135 and 171mg/kg Cr, respectively. Measurements by XAFS spectroscopy showed that the ash samples originally contained 5 and 8% of the chromium, respectively, in the hexavalent oxidation state, Cr(VI).

Nitrite reactivity with magnetite.

Under Fe(3+)-reducing conditions, soil Fe(2+) oxidation has been shown to be coupled with nitrate (NO3(-)) reduction. One possible secondary reaction is the involvement of NO3(-) and nitrite (NO2(-)) with magnetite, a mixed valence Fe(2+)/Fe(3+) mineral found in many natural environments. Currently, little information exists on NO3(-) and NO2(-) reactivity with magnetite.

Chemical speciation of Fe and Ni in residual oil fly ash fine particulate matter using X-ray absorption spectroscopy.

Epidemiological studies have linked residual oil fly ash fine particulate matter with aerodynamic diameter <2.5 μm (ROFA PM(2.5)) to morbidity and mortality from cardiovascular and respiratory illnesses.

Determination of nickel species in stack emissions from eight residual oil-fired utility steam-generating units.

XAFS spectroscopy has been used to determine the Ni species in particulate matter collected on quartz thimble filters in the stacks of eight residual (No. 6 fuel) oil-burning electric utility steam-generating units. Proper speciation of nickel in emitted particulate matter is necessary to correctly anticipate potential health risks.