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Iron and aluminum hydroxide nanopart...

Bazilevskaya, Ekaterina.

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Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes./
作者:	Bazilevskaya, Ekaterina.
面頁冊數:	187 p.
附註:	Source: Dissertation Abstracts International, Volume: 71-03, Section: B, page: 1420.
Contained By:	Dissertation Abstracts International71-03B.
標題:	Agriculture, Soil Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3399627
ISBN:	9781109659955

Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes.
Bazilevskaya, Ekaterina.

Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes. - 187 p.

Source: Dissertation Abstracts International, Volume: 71-03, Section: B, page: 1420.

Thesis (Ph.D.)--The Pennsylvania State University, 2009.

The objective of this doctoral research was to increase scientific understanding of the behavior of Fe and Al hydroxide nanoparticles in soils. These particles are of great environmental importance due to their ability to retain and transport nutrients and contaminants. Three studies were undertaken at different scales, which are documented in three manuscripts included in this dissertation.

ISBN: 9781109659955Subjects--Topical Terms:

1017824
Agriculture, Soil Science.

Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes.
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245 1 0 $a Iron and aluminum hydroxide nanoparticles in the environment: from nano-scale to the field processes.
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500 $a Source: Dissertation Abstracts International, Volume: 71-03, Section: B, page: 1420.
500 $a Adviser: Carmen Enid Martinez.
502 $a Thesis (Ph.D.)--The Pennsylvania State University, 2009.
520 $a The objective of this doctoral research was to increase scientific understanding of the behavior of Fe and Al hydroxide nanoparticles in soils. These particles are of great environmental importance due to their ability to retain and transport nutrients and contaminants. Three studies were undertaken at different scales, which are documented in three manuscripts included in this dissertation.
520 $a The first study examined the rate constants for goethite (alpha-FeOOH) crystallization from nano-particulate Fe hydroxide suspensions in the absence (0% Al) and presence (2% Al) of aluminum. One of the merits of this study was the application of a multivariate curve resolution analysis (MCR) of infrared spectra to environmentally important mixed Fe-Al hydroxide colloids in order to quantify goethite content in poorly-crystalline mixtures. Obtained rate constants were found to be equal to (7.64+/-0.67)x10-7 s-1 for 0% Al and (4.5+/-0.21) x10-7 s-1 for 2% Al hydroxides. Dissolution-precipitation mechanism was dominant in the process of goethite transformation to ferrihydrite. Further growth of goethite crystals took place either by aggregation mechanism to form polycrystalline agglomerates or alternatively by Oswald ripening to form large single crystals. The presence of aqueous Al species "poisoned" goethite's surface by disrupting the formation of hydrogen bonds thus increasing the number of non-stoichiometric hydroxyls.
520 $a The second study addressed changes of mineral composition in mixed Fe-Al hydroxide nanoparticles as a function of Al-substitution and reaction time. It was found that low Al concentrations (2-8 mol. %) lead to formation of moderately crystalline Al-goethite upon ageing, while at medium Al concentrations (10-20%) colloidal suspensions remained stable for the duration of the whole experiment (54 days), goethite formation was completely retarded, and less crystalline intermediate structure were formed. At 25% Al substitution, gibbsite Al(OH)3 microcrystalline structures appeared within the first days of experiment. In addition, to understand the mechanism of Al substitution in goethite, we explored the most energetically favorable arrangement of Al atoms within goethite by ab initio periodic density functional theory (DFT) calculations. These calculations showed that Al may form Al-O-Al clusters as opposed to evenly distributed isolated Al atoms (Al-O-Fe) in goethite structure.
520 $a The third study was conducted to investigate the relative importance of Fe and Al hydroxide nanoparticles in migration and accumulation of these elements in soils. I approached this goal by studying soil water and coatings on mineral grains from Spodosol soil, which is characterized by intensive leaching of Fe, Al, and organic matter (OM) and their accumulation in Spodosol profile. While Fe, Al and Si were mostly transported as inorganic colloids, Al also showed close association with organic matter. Fe, Al, and Si have the highest mobility in organic-rich A and Bh horizons of the spodosol profile, which suggests that the presence of organic matter facilitates transport of these elements by stabilizing the inorganic colloids. The two major mechanisms of immobilization of Fe, Al, Si and OM are (1) polymerization of metal-OM complexes and (2) surface charge neutralization of OM-inorganic colloidal aggregates. Both of these processes presumably occur when the (Fe+Al) to C ratios in the colloidal fraction increase in Bh horizon.
520 $a The presented research findings contribute to our understanding of the fundamental properties of mixed Fe- and Al-hydroxide nanoparticles and also help to predict the interactions and environmental fate of natural nanocolloids in soil profile.
590 $a School code: 0176.
650 4 $a Agriculture, Soil Science. $3 1017824
650 4 $a Nanoscience. $3 587832
650 4 $a Geochemistry. $3 539092
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690 $a 0996
710 2 $a The Pennsylvania State University. $3 699896
773 0 $t Dissertation Abstracts International $g 71-03B.
790 1 0 $a Martinez, Carmen Enid, $e advisor
790 $a 0176
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3399627