Partitioning of Metal Species during an Enriched Fuel Combustion Experiment. Speciation in the Gaseous and Particulate Phases

Abstract

Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb. The resulting mixture was burnt in a pilot-scale fuel combustion boiler under controlled conditions. After filtration of the particles, the gaseous species were sampled in the stack through a heated sampling tube simultaneously by standardized washing bottles-based sampling techniques and cryogenically. The cryogenic samples were collected at -80 degrees C for further speciation analysis by LT/GC-ICPMS. Three species of selenium and two of mercury were evidenced as volatile species in the flue gas. Thermodynamic predictions and experiments suggest the following volatile metal species to be present in the flue gas: H2Se, CSSe, CSe2, SeCl2, Hg(0), and HgCl2. Quantification of volatile metal species in comparison between cryogenic techniques and the washing bottles-based sampling method is also discussed. Concerning metal partitioning, the results indicated that under these conditions, at least 60% (by weight) of the elements Pb, Sn, Cu, Co, Tl, Mn, V, Cr, Ni, Zn, Cd, and Sb mixed to the fuel were found in the particulate matter. For As and Se, 37 and 17%, respectively, were detected in the particles, and no particulate mercury was found. Direct metal speciation in particles was performed by XPS allowing the determination of the oxidation state of the following elements: Sb(V), Tl(III), Mn(IV), Cd(II), Zn(II), Cr(III), Ni(II), Co(II), V(V), and Cu(II). Water soluble species of inorganic Cr, As, and Se in particulate matter were determined by HPLC/ICP-MS and identified in the oxidation state Cr(III), As(V), and Se(IV).

Investigation of hexadecanethiol self-assembled monolayers on cadmium tin oxide thin films

“…3A shows the XPS spectra of cadmium 3d 5/2,3/2 of bare cadmium tin oxide (dotted line) and an adlayer of 1-hexadecanethiol (solid line) on CTO. The positions of the cadmium (405.5, 412.3 eV) correspond to Cd 2+ oxidation state [39,40]. The figure shows an attenuation of approximately 41% of the signal indicative of adlayer formation.…”

Trace Metal Speciation with ICP‐MS Detection

“…Pecheyran et al developed an interface connecting packed column cryo-GC with an Elan 6000 ICP-MS for the measurement of volatile species, sampled by cryotrapping and refocused on the head of the packed column. 26,171,172 A 1 m Teflon tube (1 mm i.d.) was inserted into a 4 mm copper tubing and heated resistively to about 120 • C. The Teflon tubing was connected to the packed column (a support-filled, 8 mm o.d.…”

“…organolead in urban air, 26 volatile metal species in stack gas 171 and fuel burning processes, 172 or volatile selenium and mercury species purged and trapped from seawater. 173,174 Another set-up was used for the determination of butyltin hydrides thermodesorbed from a packed column GC, giving satisfactory peak shape for MBT and DBT, but considerable peak tailing for the least volatile species, TBT.…”

“…Volatile metal species (VMCs) have been investigated in the natural atmosphere, 20,205 special environments like landfill or sewage gases, 169,170 in flue gas from combustion processes 171,172 and in workplace air. 26 Which VMCs are of interest mainly depends on the environment analysed.…”

Nickel Carcinogenicity in Relation to the Health Risks from Residual Oil Fly Ash

“…XAFS analysis showed that the ROFAs contained 2 to 3 wt% NiSO 4 and 1.1 to 4.5 wt% NiO or a nickel-containing oxide-spinel compound not likely to be bioavailable. Supporting evidence that nickel species produced during fuel combustion should be in NiSO 4 and/or NiO forms comes from XPS (X-ray photoelectron spectroscopy) analysis of the oxidation state and binding energy of nickel during metals-enriched fuel combustion (Pavageau et al 2004).…”