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3 results on '"SO 4 2"'

1. Effect of Solution Stoichiometry on BaSO4 Crystallization from Turbidity Measurements and Modeling

Author

European Research Council, Junta de Andalucía, Peters, V. F. D., Baken, A., Seepma, S. Y. M. H., Koskamp, J. A., Fernandez-Martinez, A., Van Driessche, Alexander E. S., Wolthers, M., European Research Council, Junta de Andalucía, Peters, V. F. D., Baken, A., Seepma, S. Y. M. H., Koskamp, J. A., Fernandez-Martinez, A., Van Driessche, Alexander E. S., and Wolthers, M.

Abstract

The impact of solution stoichiometry on the nucleation and growth of BaSO was studied by measuring solution transmittance and subsequent fitting to a crystallization model. Our results show that a large excess of either Ba or SO ions inhibits both the nucleation and growth of BaSO. However, for a small excess of Ba, the growth is enhanced. The dependence of nucleation and growth rates on supersaturation and solution stoichiometry was captured by a semiempirical rate model. Hence, the solution stoichiometry is a highly relevant parameter while studying all aspects of BaSO crystallization, and it could be worthwhile to examine other minerals similarly.

Published
2024

2. Transport of carbon-bearing dusts from Iraq to Japan during Iraq's War

Author

Koshirou Miyata, Kazuhiro Sato, Ichiro Saji, Yusuke Otani, Yukiya Minami, Rie Kato, Tomoko Watanabe, Ryuji Asada, Kazue Tazaki, Tomoaki Morishita, S. Khodijah Chaerun, Hiroki Imanishi, Guoping Zhou, Hiromi Segawa, Rie Wakimoto, and Masayoshi Yamamoto

Subjects
Atmospheric Science, Air pollution, Transportation, medicine.disease_cause, Rainwater harvesting, Atmosphere, Soot, Oil field, NH 4 +, Depleted uranium, medicine, Electrical conductivity, Precipitation, General Environmental Science, Hydrology, SO 4 2, Asian Dust, Burning, Japan sea coast, Aerosol, NO 3, West wind, Acid rain, Iraq's war, Geology
Abstract

Rainwater collected during the period of February-April, 2003 in Kanazawa University and Hakui, Ishikawa Prefecture, Japan, was investigated by ion chromatography of the dissolved ions, and Scanning electron microscopy equipped with energy dispersive analyzer (SEM-EDX), electron microprobe analyzer (EPMA), transmission electron microscopy, and X-ray powder diffraction (XRD) analyses of the filtered samples. The pH, Eh, EC, dissolved oxygen (DO) and depleted U (DU) of the rainwater were also measured. The results show a rare case with low pH value of rain and high value of electrical conductivity (EC) in the rainwater during certain period. The NO 3 -, SO 4 2- and NH 4 + concentrations on 26th March, show quite high values after oil field fires on 21st March 2003. The powdery dust and carbon-bearing nm sized particles contained in the rainwater have characteristics different from that of the Asian dust (Kosa). Since 21 March, 2003 the Iraq plunged into the war, the 9 oil field fires were reported on 25 March, 2003 in Rumaylah oil field near the borderline of Kuwait. The first precipitation was caught in Kanazawa on 24 March, 2003. The pH value of the rainwater indicated a strong acid rain (pH 3.6) with black powdery dusts. The acid rain on 27th March to 2nd April (pH 3.4-4.3; 5-17mm) associated with WNW wind (2.7-4.1m/s) has continued to the first 10 days of April in Kanazawa, during the 9 oil fields were burning in Iraq. The EC in rainwater collected from 24 March to 15 April, 2003, shows high concentrations of ions, suggesting high contents of water soluble-carbon particles and soot. In the meantime, it was the highest season of sandstorms at bare dried land in Iraq from the end of March to the beginning of April. Westerly wind blew around 5500m high, and the sandstorm with 2000m wide was transported by strong wind to Zagros 3000m high mountains. The hot wind hit the Zagros Mountains and easily to join and rise to Westerly wind high by a rising air current. The 234U/ 238U activity (around 0.2) in typical depleted uranium (DU) is quite low compared with that (around 1.0) in natural uranium. The contamination of DU from the Iraq conflict may be, if any, negligibly small on undetectable level. On the other hand, the powdery dusts and carbon-bearing particles of rainwater have been produced by combustion of oil field in Iraq and they are directly cycling in our planet by Westerly wind. Black carbon particles are a product of incomplete combustion, and are the principal light-absorbing atmospheric aerosol. The result reminds us of the scientific values of short-term atmospheric environment records during Iraq's War. This has consequences for primary production of powdery dusts coming from Iraq to the atmosphere over half the globe away. © 2004 Elsevier Ltd. All rights reserved.

Published
2004

3. Changing sources of impurities to the Greenland ice sheet over the last 250 years

Author

Laj, Paolo, Palais, Julie M., Sigurdsson, Haraldur, Laj, Paolo, Palais, Julie M., and Sigurdsson, Haraldur

Abstract

Because the composition of precipitation reflects the composition of the atmosphere, polar ice cores provide a useful way of investigating past and present atmospheres. We have measured concentrations of major ions in nine sections of a central Greenland ice core and we found that concentrations of both SO42- and NO3- have increased dramatically over the last 250 years, up to three to four times the 18th century levels. Large changes have also occurred in the average concentrations of several other chemical species, such as NH4+, excess Cl, and Ca2+. We used a principal-component analysis to characterize variations of the season of maximum deposition rate of HNO3 and H2SO4 to the snow. We found that source fluctuations of H2SO4 are faithfully recorded in the Greenland snow and appear to switch their preferential time of deposition in the snow from summer to winter early in the 20th century. On the other hand, HNO3 is deposited preferentially during summer throughout the core, emphasizing the role of photochemistry in understanding nitrogen cycling in the Arctic. Anthropogenic inputs have clearly modified the behavior of several chemical compounds in the atmosphere. © 1992.

Published
1992

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