{"id":{"repo_id":"unlv","oai_identifier":"oai:oasis.library.unlv.edu:rtds-2036"},"canonical_url":"https://search.dev.ndltd.org/etd/unlv/oai:oasis.library.unlv.edu:rtds-2036","repository":{"repo_id":"unlv","name":"University of Nevada - Las Vegas","base_url":"https://oasis.library.unlv.edu/do/oai/"},"display":{"title":"Sorption and desorption of selenium in cement formulations","abstract":"Twenty-seven cementitious formulations containing three levels of water/solids (45%, 50%, 55%), three weight percentages of silica fume (0%, 10%, 20%), and three weight percentages of clay (0%, 3%, 5%) were evaluated for their ability to effectively sorb selenium at three pH levels (5.9, 8.7, 12.4). A Type V Portland cement was utilized. Distribution coefficients (K{dollar}\\sb{\\rm d}{dollar} values) determined for each cement formulation ranged from 250-1600 L kg{dollar}\\sp{-1}{dollar}. Findings suggest that increased water/solids ratios tend to maximize selenium sorption while adding silica fume or 5% clay appears to decrease sorption. A sorption/desorption study was conducted on cementitious formulations containing three levels of w/s ratios (45%, 50%, 55%) and three weight percentages of clay (0%, 3%, 5%) at several concentrations of selenium (6.5 ppb, 26 ppb, 53 ppb, 126 ppb, 784 ppb, 1510 ppb) with sodium selenite added to vary the concentrations as needed. Freundlich isotherms fitted to the data indicate irreversible sorption by selenium.","abstract_html":"Twenty-seven cementitious formulations containing three levels of water/solids (45%, 50%, 55%), three weight percentages of silica fume (0%, 10%, 20%), and three weight percentages of clay (0%, 3%, 5%) were evaluated for their ability to effectively sorb selenium at three pH levels (5.9, 8.7, 12.4). A Type V Portland cement was utilized. Distribution coefficients (K{dollar}\\sb{\\rm d}{dollar} values) determined for each cement formulation ranged from 250-1600 L kg{dollar}\\sp{-1}{dollar}. Findings suggest that increased water/solids ratios tend to maximize selenium sorption while adding silica fume or 5% clay appears to decrease sorption. A sorption/desorption study was conducted on cementitious formulations containing three levels of w/s ratios (45%, 50%, 55%) and three weight percentages of clay (0%, 3%, 5%) at several concentrations of selenium (6.5 ppb, 26 ppb, 53 ppb, 126 ppb, 784 ppb, 1510 ppb) with sodium selenite added to vary the concentrations as needed. Freundlich isotherms fitted to the data indicate irreversible sorption by selenium.","abstract_has_math":false,"creators":["Johnson, Elizabeth Ann"],"institution":"University of Nevada, Las Vegas","degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Health Physics and Diagnostic Sciences","degree_department":null,"school":null,"contributors":["Mark J. Rudin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1999,"date_issued":"1999-01-01T08:00:00Z","date_published":"1999-01-01T08:00:00Z","updated_at":"2026-07-24T05:25:04Z","subjects":[],"languages":["English"],"rights":["IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://oasis.library.unlv.edu/rtds/1037"],"render_values":[{"text":"https://oasis.library.unlv.edu/rtds/1037","href":"https://oasis.library.unlv.edu/rtds/1037","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.25669/1rxo-v25a","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mark J. 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For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10.25669/1rxo-v25a","https://oasis.library.unlv.edu/rtds/1037","https://oasis.library.unlv.edu/context/rtds/article/2036/viewcontent/uc.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Twenty-seven cementitious formulations containing three levels of water/solids (45%, 50%, 55%), three weight percentages of silica fume (0%, 10%, 20%), and three weight percentages of clay (0%, 3%, 5%) were evaluated for their ability to effectively sorb selenium at three pH levels (5.9, 8.7, 12.4). A Type V Portland cement was utilized. Distribution coefficients (K{dollar}\\sb{\\rm d}{dollar} values) determined for each cement formulation ranged from 250-1600 L kg{dollar}\\sp{-1}{dollar}. Findings suggest that increased water/solids ratios tend to maximize selenium sorption while adding silica fume or 5% clay appears to decrease sorption. A sorption/desorption study was conducted on cementitious formulations containing three levels of w/s ratios (45%, 50%, 55%) and three weight percentages of clay (0%, 3%, 5%) at several concentrations of selenium (6.5 ppb, 26 ppb, 53 ppb, 126 ppb, 784 ppb, 1510 ppb) with sodium selenite added to vary the concentrations as needed. Freundlich isotherms fitted to the data indicate irreversible sorption by selenium."]},{"key":"dc:format","label":"Dc Format","values":["pdf"]},{"key":"dc:title","label":"Title","values":["Sorption and desorption of selenium in cement formulations"]}]}],"canonical_facts":{"dc:contributor":["Mark J. Rudin"],"dc:creator":["Johnson, Elizabeth Ann"],"dc:description.abstract":["Twenty-seven cementitious formulations containing three levels of water/solids (45%, 50%, 55%), three weight percentages of silica fume (0%, 10%, 20%), and three weight percentages of clay (0%, 3%, 5%) were evaluated for their ability to effectively sorb selenium at three pH levels (5.9, 8.7, 12.4). A Type V Portland cement was utilized. Distribution coefficients (K{dollar}\\sb{\\rm d}{dollar} values) determined for each cement formulation ranged from 250-1600 L kg{dollar}\\sp{-1}{dollar}. Findings suggest that increased water/solids ratios tend to maximize selenium sorption while adding silica fume or 5% clay appears to decrease sorption. A sorption/desorption study was conducted on cementitious formulations containing three levels of w/s ratios (45%, 50%, 55%) and three weight percentages of clay (0%, 3%, 5%) at several concentrations of selenium (6.5 ppb, 26 ppb, 53 ppb, 126 ppb, 784 ppb, 1510 ppb) with sodium selenite added to vary the concentrations as needed. Freundlich isotherms fitted to the data indicate irreversible sorption by selenium."],"dc:format":["pdf"],"dc:identifier":["10.25669/1rxo-v25a","https://oasis.library.unlv.edu/rtds/1037","https://oasis.library.unlv.edu/context/rtds/article/2036/viewcontent/uc.pdf"],"dc:language":["English"],"dc:publisher":["University of Nevada, Las Vegas"],"dc:rights":["IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Sorption and desorption of selenium in cement formulations"],"dc:type":["Text"],"thesis:degree_discipline":["Health Physics and Diagnostic Sciences"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:25:04Z"}