| Surface and adsorptive properties of wood char particles in soil |
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| 作者姓名： | Joseph J. Pignatello Dongqiang ZHU Michael Sander Seokjoon Kwon Washington Braida |
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| 作者单位： | Soil and Water, Connecticut Agricultural Experiment Station, New Haven, CT, USA |
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| 摘 要： | Char and soot （black carbon, BC） are highly surface-active materials that can play an important role in contaminant fate and bioavailability in soils and sediments. This report summarizes our research on the influence of adsorbate structure and BC properties on adsorption of organic compounds, and the possible attenuation of BC surface activity by humic substances in the environment. The BC was a maple wood char formed at 400 ℃ in air and under other conditions. The solutes were polar and apolar aromatic compounds. The following points will be discussed. （1） By comparing adsorption to nonporous graphite, it was shown that molecular sieving effects （steric restriction） in the char micropore system occur in the order of increasing substitution on the benzene ring and in the order of increasing fused ring size. （2） By accounting for hydrophobic and steric effects it was shown that aromatic rings substituted with strongly pi-electron-accepting functional groups, such as nitro, undergo pi-pi electron donor-acceptor （EDA） interactions with the pi-donor polyaromatic （graphene） surface of the char. The free energy of adsorption due to pi-pi EDA interactions correlated with the free energy of molecular complexation in chloroform with model compounds representing the graphene surface （napthalene, phenanthrene, pyrene）. （3） A series of chars were prepared of different polarity （O content） but similar surface area and pore size distribution by varying temperature and atmosphere. Single- and bi-solute experiments showed that polar interactions with surface O are not a significant driving force for adsorption of polar compounds. Rather, surface O attracts water molecule clusters that inhibit adsorption of both polar and nonpolar compounds by competition. （4） Aging of char particles in a soil-water suspension strongly reduced char SA and sorption of added benzene. Studies were conducted with dissolved humic （HA） acid, HA-char co-precipitates, Ala＋-HA-char co-flocculates, and soybean oil representing humic lipid components.
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| 关 键 词： | 土壤污染 污染化学 吸附作用 腐殖质 颗粒 |
Surface and adsorptive properties of wood char particles in soil |
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| Joseph J. Pignatello Dongqiang ZHU Michael Sander Seokjoon Kwon Washington Braida.Surface and adsorptive properties of wood char particles in soil[J].Chinese Journal of Geochemistry,2006,25(B08):260-261. |
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| Abstract: | |
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| Keywords: | sorption pollutant black carbon humic substance |
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