{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/22008"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/22008","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The precipitation of uniform silica particles through the controlled hydrolysis of silicon alkoxides","abstract":"The formation of uniform silica particles by the alkoxide route has been investigated. Rates of chemical reactions involved in the precipitation are reported and linked to particle growth rates. Seeded growth experiments indicate that reactions between soluble species occur at rates that are independent of the size and number density of the seed particles. Estimates of hydrolyzed alkoxide concentrations based on solution conductivity suggest that the soluble silica concentration is above that required for nucleation until late in the reaction. These results are consistent with a particle growth mechanism whereby reactions occurring in solution proceed independently of the presence of particles, resulting in the formation of silica nuclei, which aggregate to form larger particles. This hypothesis has been further checked by carrying out precipitations at different electrolyte concentrations. While rates of hydrolysis and condensation are not substantially affected by NaCl concentrations up to 10$\\sp{\\rm -2}$ M, final particle size increases drastically.","abstract_html":"The formation of uniform silica particles by the alkoxide route has been investigated. Rates of chemical reactions involved in the precipitation are reported and linked to particle growth rates. Seeded growth experiments indicate that reactions between soluble species occur at rates that are independent of the size and number density of the seed particles. Estimates of hydrolyzed alkoxide concentrations based on solution conductivity suggest that the soluble silica concentration is above that required for nucleation until late in the reaction. These results are consistent with a particle growth mechanism whereby reactions occurring in solution proceed independently of the presence of particles, resulting in the formation of silica nuclei, which aggregate to form larger particles. This hypothesis has been further checked by carrying out precipitations at different electrolyte concentrations. While rates of hydrolysis and condensation are not substantially affected by NaCl concentrations up to 10$\\sp{\\rm -2}$ M, final particle size increases drastically.","abstract_has_math":true,"creators":["Bogush, Gregory Harry"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Chemical Engineering","degree_department":null,"school":null,"contributors":["Zukoski, Charles F."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:26:00Z","date_published":"2011-05-07T13:26:00Z","updated_at":"2026-07-22T22:25:19Z","subjects":["Engineering, Chemical"],"languages":["eng"],"rights":["Copyright 1990 Bogush, Gregory Harry"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9114178","(UMI)AAI9114178"],"render_values":[{"text":"AAI9114178","href":null,"code":true},{"text":"(UMI)AAI9114178","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/22008","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Zukoski, Charles F."]},{"key":"dc:creator","label":"Author","values":["Bogush, Gregory Harry"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:26:00Z","10000-01-01","1990"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Chemical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Chemical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1990 Bogush, Gregory Harry"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9114178","(UMI)AAI9114178","http://hdl.handle.net/2142/22008"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The formation of uniform silica particles by the alkoxide route has been investigated. Rates of chemical reactions involved in the precipitation are reported and linked to particle growth rates. Seeded growth experiments indicate that reactions between soluble species occur at rates that are independent of the size and number density of the seed particles. Estimates of hydrolyzed alkoxide concentrations based on solution conductivity suggest that the soluble silica concentration is above that required for nucleation until late in the reaction. These results are consistent with a particle growth mechanism whereby reactions occurring in solution proceed independently of the presence of particles, resulting in the formation of silica nuclei, which aggregate to form larger particles. This hypothesis has been further checked by carrying out precipitations at different electrolyte concentrations. While rates of hydrolysis and condensation are not substantially affected by NaCl concentrations up to 10$\\sp{\\rm -2}$ M, final particle size increases drastically.","An aggregative growth model has been developed and tested with rate and particle size distribution data gathered under various reaction conditions. Smoluchowski population balance equations with a source term were solved for conditions applicable to the precipitations studied. Size dependant aggregation rate constants were determined from estimates of particle properties. By assuming that particles grow solely by aggregation, the model provides good estimates of final particle size distribution parameters from measured reaction rates.","Made available in DSpace on 2011-05-07T13:26:00Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9114178.pdf: 5462041 bytes, checksum: 162fba749954ef255d19d09b7ec80f8a (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:54:42Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:25:26-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["The precipitation of uniform silica particles through the controlled hydrolysis of silicon alkoxides"]}]}],"canonical_facts":{"dc:contributor":["Zukoski, Charles F."],"dc:creator":["Bogush, Gregory Harry"],"dc:date":["2011-05-07T13:26:00Z","10000-01-01","1990"],"dc:description":["The formation of uniform silica particles by the alkoxide route has been investigated. Rates of chemical reactions involved in the precipitation are reported and linked to particle growth rates. Seeded growth experiments indicate that reactions between soluble species occur at rates that are independent of the size and number density of the seed particles. Estimates of hydrolyzed alkoxide concentrations based on solution conductivity suggest that the soluble silica concentration is above that required for nucleation until late in the reaction. These results are consistent with a particle growth mechanism whereby reactions occurring in solution proceed independently of the presence of particles, resulting in the formation of silica nuclei, which aggregate to form larger particles. This hypothesis has been further checked by carrying out precipitations at different electrolyte concentrations. While rates of hydrolysis and condensation are not substantially affected by NaCl concentrations up to 10$\\sp{\\rm -2}$ M, final particle size increases drastically.","An aggregative growth model has been developed and tested with rate and particle size distribution data gathered under various reaction conditions. Smoluchowski population balance equations with a source term were solved for conditions applicable to the precipitations studied. Size dependant aggregation rate constants were determined from estimates of particle properties. By assuming that particles grow solely by aggregation, the model provides good estimates of final particle size distribution parameters from measured reaction rates.","Made available in DSpace on 2011-05-07T13:26:00Z (GMT). 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