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Florida International University

1. Jiang, Ping. Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches.

Degree: PhD, Chemistry, 2016, Florida International University

Mercury (Hg) is a global contaminant of ecosystems and human health risk, with complicated biogeochemical processes. Mercury sulfide (HgS) dissolution has been suggested as a key process in Hg cycling, as it could potentially increase the pool of inorganic Hg (iHg) for the production of methylmercury (MeHg). Despite previous sporadic observations of enhanced HgS dissolution under certain conditions, much remains unclear on mechanisms of HgS dissolution. The objective of my research was to advance the mechanistic understanding of HgS dissolution, concerning re-adsorption of released Hg, effects of thiol-ligands, and Hg speciation. Considering the lack of feasible techniques to differentiate dissolution and re-adsorption processes, I first developed an efficient method using isotope tracer and isotope dilution techniques to investigate the re-adsorption of released Hg during HgS dissolution. The HgS dissolution rate with consideration of re-adsorption was two times the rate calculated from detecting Hg alone in the presence of O2, indicating the importance of Hg re-adsorption during HgS dissolution. I further examined the role of Hg-ligand complexation in HgS dissolution and Hg(II) re-adsorption using a thermodynamic adsorption method, selecting L-cysteine (Cys) as a model compound for low molecular weight ligands and Waskish fulvic acid (FA) for natural dissolved organic matter (DOM). My results suggest that the presence of Cys enhanced HgS dissolution through the decreased re-adsorption of Hg-Cys complex, whereas Waskish FA inhibited HgS dissolution, possibly because of the adsorption of FA on HgS surface that covered dissolution sites. I further employed a geochemical modeling method to study Hg speciation and the relation of iHg speciation to MeHg, aiming to provide a methodological example for potentially evaluating the implications of Hg species distribution during HgS dissolution on MeHg production. I applied geochemical model PHREEQC to the Florida Everglades, a well-studied wetland with model input parameters available, to determine the distribution of iHg in surface water at different sites. The modeling results suggest that sulfide and DOM govern iHg speciation, and the Hg-sulfide and Hg-DOM species are related to MeHg in environmental media but not fish, suggesting the importance of iHg speciation in MeHg production and the complexity of Hg bioaccumulation. Advisors/Committee Members: Yong Cai, Rudolf Jaffé, Bruce McCord, Martin Quirke, Georgio Tachiev.

Subjects/Keywords: Mercury sulfide; Dissolution; Re-adsorption; Isotope tracer technique; Dissolved organic matter; Everglades; Hg speciation; PHREEQC; Hg methylation; Analytical Chemistry; Environmental Chemistry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Jiang, P. (2016). Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches. (Doctoral Dissertation). Florida International University. Retrieved from http://digitalcommons.fiu.edu/etd/3027 ; 10.25148/etd.FIDC001206 ; FIDC001206

Chicago Manual of Style (16th Edition):

Jiang, Ping. “Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches.” 2016. Doctoral Dissertation, Florida International University. Accessed November 16, 2019. http://digitalcommons.fiu.edu/etd/3027 ; 10.25148/etd.FIDC001206 ; FIDC001206.

MLA Handbook (7th Edition):

Jiang, Ping. “Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches.” 2016. Web. 16 Nov 2019.

Vancouver:

Jiang P. Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches. [Internet] [Doctoral dissertation]. Florida International University; 2016. [cited 2019 Nov 16]. Available from: http://digitalcommons.fiu.edu/etd/3027 ; 10.25148/etd.FIDC001206 ; FIDC001206.

Council of Science Editors:

Jiang P. Mercury Sulfide Dissolution in Environmental Conditions: Thermodynamic and Kinetic Approaches. [Doctoral Dissertation]. Florida International University; 2016. Available from: http://digitalcommons.fiu.edu/etd/3027 ; 10.25148/etd.FIDC001206 ; FIDC001206


Univerzitet u Beogradu

2. Karanac, Milica, 1983-. Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode.

Degree: Tehnološko-metalurški fakultet, 2018, Univerzitet u Beogradu

Tehničko-tehnološke nauke - Inženjerstvo zaštite životne sredine / Applied Science - Environmental Engineering

Cilj ove disertacije bio je ispitivanje mogućnosti primene modifikovanih oblika elektrofilterskog pepela sa kalcijum-hidroksidom (Ca(OH)2) i oksidima železa za efikasno uklanjanje jona metala iz otpadne vode. U okviru rada sintetizovani su novi adsorpcioni materijali i ispitana je ponovna upotreba iskorišćenog adsorbenta za proizvodnju građevinskog materijala (GM) čime se ostvaruje nova upotrebna vrednost i zaokružuje životni ciklus pepela. Prvi postupak modifikacije pepela (eng. Fly Ash, FA) bio je suvo mešanje sa Ca(OH)2, a drugi siteza u koloni sa železo(II, III)-oksidom (Fe3O4) u obliku magnetita (M) i železo(III)-hidroksidom (α–FeOOH) u obliku getita (G). Dobijeni adsorbenti ispitivani su i označeni kao: FA/Ca(OH)2MFA, FA/MFAM i FA/GFAG. Karakterizacija sirovih uzoraka pepela i dobijenih adsorbenata izvršena je primenom sledećih tehnika: granulometrijska i elementarna analiza, gama spektrometrija (eng. γSpectrometry), tačka nultog naelektrisanja (eng. The Point of Zero Charge, pHpzc), rendgenska difrakciona analiza (eng. XRay Difraction, XRD), metoda adsorpciono/desorpcione izoterme adsorpcije gasa (eng. Brunauer–Emmett–Teller, BET), skenirajuća elektronska mikroskopija (eng. Scanning Electron Microscopy, SEM), infracrvena spektrometrija sa Furijeovom transformacijom (eng. FourierTransform Infrared Spectroscopy, FTIR) i Mosbauerova spektroskopija (eng. Mössbauer Spectroscopy, MS). Ispitana je efikasnost uklanjanja Zn2+, Pb2+ i As(V) primenom MFA i As(V) primenom FAM i FAG adsorbenata. Efikasnost adsorpcije ispitivana je varijacijom mase adsorbenta, temperature, vremena trajanja procesa i pH vrednosti rastvora. Adsorpcija je ispitivana u laboratorijskim uslovima u šaržnom sistemu. Za pripremu adsorbenta za izradu GM adsorpcioni eksperimenti izvedeni su na poluindustrijskom postrojenju. Primenom metode odziva površina određeni su optimalni parametri primenjeni za sintezu adsorbenata i izvođenje adsorpcionih procesa. Maksimalni adsorpcioni kapacitet MFA za uklanjanje jona Zn2+, Pb2+ i As(V), izračunati primenom Lengmirovog (eng. Langmuir) modela, iznosili su 33,13, 26,06 i 29,71 mg g1, redom. ..

Advisors/Committee Members: Pavićević, Vladimir, 1960-.

Subjects/Keywords: fly ash; chemical activation; magnetite; goethite; heavy metals; arsenic; adsorption; (re)valorization of waste; construction material

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Karanac, Milica, 1. (2018). Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode. (Thesis). Univerzitet u Beogradu. Retrieved from https://fedorabg.bg.ac.rs/fedora/get/o:19001/bdef:Content/get

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Karanac, Milica, 1983-. “Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode.” 2018. Thesis, Univerzitet u Beogradu. Accessed November 16, 2019. https://fedorabg.bg.ac.rs/fedora/get/o:19001/bdef:Content/get.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Karanac, Milica, 1983-. “Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode.” 2018. Web. 16 Nov 2019.

Vancouver:

Karanac, Milica 1. Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode. [Internet] [Thesis]. Univerzitet u Beogradu; 2018. [cited 2019 Nov 16]. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:19001/bdef:Content/get.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Karanac, Milica 1. Primena elektrofilterskog pepela modifikovanog kalcijum-hidroksidom i oksidima železa za uklanjanje jona teških metala iz vode. [Thesis]. Univerzitet u Beogradu; 2018. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:19001/bdef:Content/get

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Freie Universität Berlin

3. Pauls, Christian. Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface.

Degree: 2012, Freie Universität Berlin

The interaction of carbon monoxide and gold adsorbed on a rhenium single crystal surface under UHV conditions has been studied in the temperature range between 120 and 1100 K. In order to understand the coadsorption system the separate systems CO+Re and Au+Re have also been investigated in some detail. Depending on temperature competitive as well as cooperative adsorption of CO occurs. Above 300 K no CO-Au mixed phases exist and CO adsorption leads to segregation in gold and CO island. Therefore the coadsorption system above room temperature can be largely understood by the properties of the separate CO/Re(10-10) and Au/Re(10-10) systems. The adsorption of CO on the clean Re surface has been studied by TPD (temperature-programmed thermal desorption), LEED (low energy electron diffraction) and measurement of the work function change ΔΦ . TPD shows desorption from two types of binding states caused by dissociative (β) and intact (α) CO adsorption with binding energies of 188-207kJ/mol (β) and 95-118kJ/mol (α). Above 500 K the adsorbate consists entirely of dissociated CO with a maximum coverage of 0.25 ML and forms well- ordered superstructures with c(2x4) and p(1x2)-symmetry at the respective optimal coverages of 0.125 ML and 0.25 ML. The two ordered phases undergo an order-disorder transition with transition temperatures between 660 and 690 K. In both structures C and O atoms are randomly distributed on sites of the respective super lattices. The work function change ΔΦ upon adsorption of CO in the beta states is proportional to coverage and amounts to 400 mV at maximum coverage. From ΔΦ measurements adsorption isotherms were derived in the temperature range between 580-740 K. These can be described by a second- order Temkin model with isosteric heats of 180-185 kJ/mol at half coverage. The deposition of Au vapor at 800 K on the rhenium surface has been investigated by MEED (medium energy electron diffraction) and LEED-IV- measurements. The gold films grow in a Stranski-Krastanov mode, so that a first closed Au layer is formed before three dimensional growth sets in. A LEED-IV analysis of this closed layer with (1x1)-symmetry shows a pseudomorphic bilayer arrangement of the gold atoms with a coverage of 2 ML (1 ML = 0.81 x 1015atoms/cm2). At higher gold coverages up to 8 ML a (1x8)-LEED structure develops that can be attributed to a hexagonal reconstructed goldlayer on top of pseudomorphic hcp Au terraces. For coverages below the coverage of the bilayer a series of (1xn)-LEED patterns has been observed. Starting with a coverage of 0.28 ML islands with (1x3)-structure and a local coverage of 4/3 ML form. These islands coexist with a disordered dilute gold phase up to 1.33 ML. At higher coverages gold phases with increasing n (n = 4, 5, 6) and with corresponding local coverages of 6/4, 8/5, and 10/6 ML are formed until the (1x1) bilayer is reached at 2 ML. At intermediate coverages domains of two adjacent ordered phases coexist as shown by spot splitting and spot shifting in the associated LEED patterns. These ordered… Advisors/Committee Members: [email protected] (contact), m (gender), Prof. Dr. Thomas Risse (firstReferee), Prof. Dr. Klaus Christmann (furtherReferee).

Subjects/Keywords: spreading pressure; adsorption; CO; epitaxy; gold; bimetallic surface Re(10-10); twodimensional compression; 500 Naturwissenschaften und Mathematik::540 Chemie

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Pauls, C. (2012). Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface. (Thesis). Freie Universität Berlin. Retrieved from http://dx.doi.org/10.17169/refubium-11672

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Pauls, Christian. “Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface.” 2012. Thesis, Freie Universität Berlin. Accessed November 16, 2019. http://dx.doi.org/10.17169/refubium-11672.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Pauls, Christian. “Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface.” 2012. Web. 16 Nov 2019.

Vancouver:

Pauls C. Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface. [Internet] [Thesis]. Freie Universität Berlin; 2012. [cited 2019 Nov 16]. Available from: http://dx.doi.org/10.17169/refubium-11672.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pauls C. Two-dimensional compression of ultrathin goldfilms by adsorption of CO on a Re(10-10) surface. [Thesis]. Freie Universität Berlin; 2012. Available from: http://dx.doi.org/10.17169/refubium-11672

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.