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Contributions to the Development of Engineered Amorphous Carbons for Environmental Applications.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Contributions to the Development of Engineered Amorphous Carbons for Environmental Applications./
Author:	Apasiku, Michael Atogiba Ayiania.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
Description:	418 p.
Notes:	Source: Dissertations Abstracts International, Volume: 82-04, Section: B.
Contained By:	Dissertations Abstracts International82-04B.
Subject:	Natural resource management. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27737192
ISBN:	9798678104793

Contributions to the Development of Engineered Amorphous Carbons for Environmental Applications.
Apasiku, Michael Atogiba Ayiania.

Contributions to the Development of Engineered Amorphous Carbons for Environmental Applications. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 418 p.

Source: Dissertations Abstracts International, Volume: 82-04, Section: B.

Thesis (Ph.D.)--Washington State University, 2020.

This item must not be sold to any third party vendors.

Understanding the structural changes of biochars and the characterization of the active sites is very crucial in engineering efficient biochars for environmental services. In this dissertation we developed Raman and XPS spectra deconvolution schemes to characterize N-doped amorphous carbons. The information gathered from the computational spectra of model structures was used to guide the development of rational deconvolution schemes for Raman and XPS spectra of nitrogen-doped biochars.Density functional theory was used to study the thermodynamic stability of nitrogen functionalities in graphene structures as a function of temperature and pressure, providing atomistic insight into the most favorable functionalized configurations. The information gained with theoretical calculations was used to develop engineered biochars for environmental services. We report the production and use of a carbonaceous adsorbent from AD fibers for the removal of H2S from biogas and phosphate from aqueous effluents. The CO2 modified biochars did a good job at phosphate removal (37 mg/g). However, when the modification conditions were changed to ammonia and metal impregnation (Mg and Ca), to form N-Metal-doped biochars, the adsorption capacity increased by 9 folds (N-Mg-Char) compared to the CO2 modified biochar. The results demonstrate there is synergistic effect between nitrogen metal that renders the high capacity of the biochar. Our experimental and modeling studies confirm that the Mg can be in two forms: as part of porphyrin structures or in the edge of the graphene sheets. The results show that the stability of the Mg and Ca both increases with the number of nitrogen atoms resulting in the centered actives sites becoming more stable than the edge active sites. The data suggest that the phosphate diffuses from the aqueous phase to the surface of the biochar and interacts directly with the Ca and the Mg. The DFT calculation suggests the phosphate binds strongly to the centered sites than to the edge sites. The dissertation ends with a study of biochars derived from municipal solid wastes. High level of trace metals, such as arsenic, lead and mercury were found in the biochars. Hence biochar from a range of feedstock must be thoroughly characterized before recommending their application.

ISBN: 9798678104793Subjects--Topical Terms:

589570
Natural resource management.
Subjects--Index Terms:

Biochar

Contributions to the Development of Engineered Amorphous Carbons for Environmental Applications.
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260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2020
300 $a 418 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-04, Section: B.
500 $a Advisor: Garcia-Perez, Manuel;McEwen, Jean-Sabin.
502 $a Thesis (Ph.D.)--Washington State University, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a Understanding the structural changes of biochars and the characterization of the active sites is very crucial in engineering efficient biochars for environmental services. In this dissertation we developed Raman and XPS spectra deconvolution schemes to characterize N-doped amorphous carbons. The information gathered from the computational spectra of model structures was used to guide the development of rational deconvolution schemes for Raman and XPS spectra of nitrogen-doped biochars.Density functional theory was used to study the thermodynamic stability of nitrogen functionalities in graphene structures as a function of temperature and pressure, providing atomistic insight into the most favorable functionalized configurations. The information gained with theoretical calculations was used to develop engineered biochars for environmental services. We report the production and use of a carbonaceous adsorbent from AD fibers for the removal of H2S from biogas and phosphate from aqueous effluents. The CO2 modified biochars did a good job at phosphate removal (37 mg/g). However, when the modification conditions were changed to ammonia and metal impregnation (Mg and Ca), to form N-Metal-doped biochars, the adsorption capacity increased by 9 folds (N-Mg-Char) compared to the CO2 modified biochar. The results demonstrate there is synergistic effect between nitrogen metal that renders the high capacity of the biochar. Our experimental and modeling studies confirm that the Mg can be in two forms: as part of porphyrin structures or in the edge of the graphene sheets. The results show that the stability of the Mg and Ca both increases with the number of nitrogen atoms resulting in the centered actives sites becoming more stable than the edge active sites. The data suggest that the phosphate diffuses from the aqueous phase to the surface of the biochar and interacts directly with the Ca and the Mg. The DFT calculation suggests the phosphate binds strongly to the centered sites than to the edge sites. The dissertation ends with a study of biochars derived from municipal solid wastes. High level of trace metals, such as arsenic, lead and mercury were found in the biochars. Hence biochar from a range of feedstock must be thoroughly characterized before recommending their application.
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650 4 $a Soil sciences. $3 2122699
650 4 $a Thermodynamics. $3 517304
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650 4 $a Environmental engineering. $3 548583
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650 4 $a Organic chemistry. $3 523952
653 $a Biochar
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653 $a Engineered char
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653 $a Nitrogen-doped biochars
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