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X-ray absorption spectroscopy is used to investigate the speciation of sorbed copper in heated fly ash. CuO and Cu(OH) 2 are determined to be the principal copper species in the Cu-sorbing fly ash heated at 500 °C for 2 h. Heating the Cu-sorbing fly ash to 900 °C or 1100 °C can result in the formation of CuSO 4 , representing 41% and 32% of the total copper, respectively. Ash sintering and/or co-melting at 900 and 1100 °C occur, thereby triggering chemical reaction between CuO/Cu(OH) 2 and sulfur compounds.

Speciation of titanium in the CuO/TiO 2 thin film (synthesized by radio frequency magnetron sputtering) during photocatalytic decomposition of CHCl 3 has been studied by in situ X-ray absorption near-edge structural (XANES) spectroscopy. Little perturbation was observed in the Ti K-edge XANES spectra of the CuO/TiO 2 during photocatalysis. However, by prolonging the UV/VIS radiation to 90 min, the copper K-edge white line absorbance was enhanced suggesting electron donation (from the encapsulated TiO 2 ) to surface CuO, which was also observed by electron spectroscopy for chemical analysis (ESCA) spectroscopy.

Nano size (o100 nm) pollutants have been controlled negligibly in traditional air pollution control devices. Phosphor particulates escaped from filtration systems (bag houses or electrostatic precipitators) of used TVs, monitors or FEDs disassembling processes are frequently found in nano or submicron sizes. Experimentally, in a very short contact time (o2 min), more than 90% of the nano phosphor particulates could be abstracted into room temperature ionic liquid (RTIL) (e.g., [C4min][PF6]). The least-square fitted X-ray absorption near edge structural (XANES) spectra show that nano ZnS (88%) and ZnO (12%) could be suspended in the RTIL for at least 10 days. r 2006 Elsevier Ltd. All rights reserved.

Fly ashes collected from waste heat boilers in the incineration process may possess representative chemical structure of toxic metals during incineration and their changes in the quench process at 1125–553 K and 503–493 K, respectively. Note that copper may play an important role in catalytic formation of dioxins during incineration. Speciation of copper in the fly ashes has, therefore, been studied by X-ray absorption spectroscopy in the present work. About 24% of nano copper in the fly ash was observed by least-squares-fitted XANES (X-ray absorption near edge structural) spectroscopy. Sintering of the fly ash at 1423 K for 30 min led to a reduction of the nano CuO content to 8%.

Speciation of chromium in swarf wastes pyrolyzed at 673–873 K has been studied by X-ray absorption spectroscopy in the present work. The least-square fitted X-ray absorption near edge structural (XANES) spectrum shows that Cr 3 C 2 (84%) was the main chromium species in the untreated swarf. A small amount of CrO 3 and Cr 2 O 3 was also found. During pyrolysis at 673–873 K, Cr (35%) and FeCr 2 O 4 (24%) were formed with disappearance of about 43% of Cr 3 C 2 in the swarf. By extended X-ray absorption fine structural (EXAFS) spectroscopy, we found that metallic Cr (with Cr Cr bond distances of 2.56–2.59 A) was formed during pyrolysis. At least two reaction paths might be involved during pyrolysis at 673–873 K: (1) reduction of Cr 3 C 2 to metallic Cr and (2) formation of FeCr 2 O 4 via reactions of chromium oxides and iron oxides.