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Awual, M. R.; Yaita, Tsuyoshi; Okamoto, Yoshihiro
Sensors and Actuators B; Chemical, 203, p.71 - 80, 2014/11
Times Cited Count：177 Percentile：99.21(Chemistry, Analytical)Terada, Hiroaki; Ueda, Hiromasa*; Wang, Z.*
Atmospheric Environment, 36(3), p.503 - 509, 2002/01
Times Cited Count：49 Percentile：70.13(Environmental Sciences)Acid rain and its neutralization by yellow-sand in East Asia was investigated numerically by an Air Quality Prediction Modeling System (AQPMS). AQPMS consists of advection, diffusion, dry and wet deposition, gas- and liquid-phase chemistry. A new deflation module of the yellow-sand was designed to provide explicit information on the dust loading, and linked to the AQPMS. For model validation, the predicted pH values and sulfate- and nitrate-ion levels of precipitation, together with the surface concentrations of gaseous pollutants, were compared with measured values at atmospheric monitoring stations, and a reasonable agreement was obtained. Firstly, trend of the acid rain in East Asia due to the rapid increase of Chinese pollutants emission was investigated, and a remarkably rapid increase of acid rain area was predicted in the period from 1985 to 1995. Secondly, the simulation results of April 1995 exhibited a strong neutralization of the precipitation by the yellow-sand.
Sakuma, Hiroshi*; Tachi, Yukio; Yotsuji, Kenji; Kawamura, Katsuyuki*
no journal, ,
Clay minerals are good adsorbents of many toxic elements of molecules in natural environment, because of their large surface areas and their high affinity to organic and inorganic materials. The adsorption sites of ions and molecules on the basal planes can be estimated by experiments and computer simulations based on the simple surface structure. While the adsorption of ions and molecules on the edge planes of clay minerals is poorly understood due to the absence of established model of the edge structures. In this study, the edge structures of montmorillonite were examined by the first-principles calculations based on the density functional theory. The effect of isomorphous substitution, layer charge, and positions of interlayer cations was evaluated for four different edge planes by calculating the surface energy. The acidity constant of the edges were calculated by an empirical method. We will discuss possible adsorption sites of cations on these edges.
