東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Characterization of humic substances...

Wang, Kaijun.

FindBook

Google Book

Amazon

博客來

Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions./
作者:	Wang, Kaijun.
面頁冊數:	123 p.
附註:	Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5748.
Contained By:	Dissertation Abstracts International66-11B.
標題:	Agriculture, Soil Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3193955
ISBN:	9780542383755

Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions.
Wang, Kaijun.

Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions. - 123 p.

Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5748.

Thesis (Ph.D.)--University of Massachusetts Amherst, 2005.

Humic substances (HS) are major components of soil organic matter (SOM). Advances on characterization of HS and their interaction with minerals can provide a more fundamental understanding of HS functions in soils. The objectives of this research were to investigate potential fractionation of humic acid (HA) upon adsorption on minerals and to determine any variation on structure and sorption properties of humin extracted by different methods. Nuclear magnetic resonance (NMR) spectra, for the first time, provided direct evidence that HA was fractionated during adsorption on mineral surfaces. Aliphatic fractions of HA were preferentially adsorbed while aromatic fractions were more likely to be left in solution. The bound HA fractions had higher sorption linearity (N) and affinity (KOC) for phenanthrene than the source HA. For montmorillonite and kaolinite, the KOC values of adsorbed HA were up to several times higher than that of the source HA as a result of fractionation. Extraction procedures had substantial influences in structure and sorption characteristics of humin. Humin from 0.1 M NaOH exhaustive extraction and 6 M HF/HCl extraction at 60°C had relatively more aliphatic components as compared with 1 M HF extracted humin. The treatment of 6 M HF/HCl at 60°C reduced more than 50% carbohydrate components (50-108 ppm) and enriched amorphous poly(methylene) domains. The NaOH exhaustively extracted humin had the most nonlinear sorption isotherms and the HF extracted humin had the lowest KOC. We concluded that both NaOH and NaOH-HF procedures were appropriate approaches for humin extraction but the extraction with 6 M HF/HCl at 60 °C would be discouraged for use due to structural modifications of humin both chemically and physically. Segmental mobility of HA in solution was also explored by NMR relaxation. Proton spin-lattice relaxation time (T1) of HAs ranged from 0.3 to 0.8 s in d6-DMSO, and from 0.26 to 2.3 s in 0.5 M NaOD at 300 MHz. Proton correlation time of HA in solvents was in an order of 10-10 s. Carbohydrate was identified as the largest and the most immobile components while aliphatic and aromatic fragments were relatively smaller and more mobile in aqueous solution.

ISBN: 9780542383755Subjects--Topical Terms:

1017824
Agriculture, Soil Science.

Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions.
LDR:03182nmm 2200289 4500 001 1822909
005 20061127103239.5
008 130610s2005 eng d
020 $a 9780542383755
035 $a (UnM)AAI3193955
035 $a AAI3193955
040 $a UnM $c UnM
100 1 $a Wang, Kaijun. $3 1912037
245 1 0 $a Characterization of humic substances and non-ideal phenanthrene sorption as affected by clay-humic interactions.
300 $a 123 p.
500 $a Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5748.
500 $a Director: Baoshan Xing.
502 $a Thesis (Ph.D.)--University of Massachusetts Amherst, 2005.
520 $a Humic substances (HS) are major components of soil organic matter (SOM). Advances on characterization of HS and their interaction with minerals can provide a more fundamental understanding of HS functions in soils. The objectives of this research were to investigate potential fractionation of humic acid (HA) upon adsorption on minerals and to determine any variation on structure and sorption properties of humin extracted by different methods. Nuclear magnetic resonance (NMR) spectra, for the first time, provided direct evidence that HA was fractionated during adsorption on mineral surfaces. Aliphatic fractions of HA were preferentially adsorbed while aromatic fractions were more likely to be left in solution. The bound HA fractions had higher sorption linearity (N) and affinity (KOC) for phenanthrene than the source HA. For montmorillonite and kaolinite, the KOC values of adsorbed HA were up to several times higher than that of the source HA as a result of fractionation. Extraction procedures had substantial influences in structure and sorption characteristics of humin. Humin from 0.1 M NaOH exhaustive extraction and 6 M HF/HCl extraction at 60°C had relatively more aliphatic components as compared with 1 M HF extracted humin. The treatment of 6 M HF/HCl at 60°C reduced more than 50% carbohydrate components (50-108 ppm) and enriched amorphous poly(methylene) domains. The NaOH exhaustively extracted humin had the most nonlinear sorption isotherms and the HF extracted humin had the lowest KOC. We concluded that both NaOH and NaOH-HF procedures were appropriate approaches for humin extraction but the extraction with 6 M HF/HCl at 60 °C would be discouraged for use due to structural modifications of humin both chemically and physically. Segmental mobility of HA in solution was also explored by NMR relaxation. Proton spin-lattice relaxation time (T1) of HAs ranged from 0.3 to 0.8 s in d6-DMSO, and from 0.26 to 2.3 s in 0.5 M NaOD at 300 MHz. Proton correlation time of HA in solvents was in an order of 10-10 s. Carbohydrate was identified as the largest and the most immobile components while aliphatic and aromatic fragments were relatively smaller and more mobile in aqueous solution.
590 $a School code: 0118.
650 4 $a Agriculture, Soil Science. $3 1017824
650 4 $a Environmental Sciences. $3 676987
650 4 $a Geochemistry. $3 539092
690 $a 0481
690 $a 0768
690 $a 0996
710 2 0 $a University of Massachusetts Amherst. $3 1019433
773 0 $t Dissertation Abstracts International $g 66-11B.
790 1 0 $a Xing, Baoshan, $e advisor
790 $a 0118
791 $a Ph.D.
792 $a 2005
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3193955