{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/122084"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/122084","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effects of pCO2 on hydroxyapatite formation and its stability: Implications for understanding phosphorus availability in calcareous soil","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","abstract_has_math":false,"creators":["Kalita, Shravani"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Natural Res & Env Sciences","degree_department":null,"school":null,"contributors":["Arai, Yuji"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-12","date_published":"2023-12","updated_at":"2026-07-22T22:25:00Z","subjects":["Hydroxyapatite","Calcareous Soils","Partial Pressure Of Carbon Dioxide","Carbonate Activity","Phosphorus Cycle"],"languages":["en","eng"],"rights":["Copyright 2023 Shravani Kalita"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/122084","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Arai, Yuji"]},{"key":"dc:creator","label":"Author","values":["Kalita, Shravani"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2023-12","2023-11-16"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Res & Env Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"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":["Hydroxyapatite","Calcareous Soils","Partial Pressure Of Carbon Dioxide","Carbonate Activity","Phosphorus Cycle"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2023 Shravani Kalita"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/122084"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","The student, Shravani Kalita, accepted the attached license on 2023-11-05 at 12:43.","The student, Shravani Kalita, submitted this Thesis for approval on 2023-11-05 at 17:17.","This Thesis was approved for publication on 2023-11-16 at 16:49.","DSpace SAF Submission Ingestion Package generated from Vireo submission #19367 on 2024-03-01 at 13:29:08","Hydroxyapatite is an important phosphorus (P) sink in calcareous soils. The activity of carbonate in soil pore water, however, is often underestimated because soil respiration and solution-calcite equilibria could elevate pCO2 much greater than 415 ppmv. Thus far, the role of pCO2 in hydroxyapatite formation in calcareous soils has not been extensively investigated. Accordingly, the effects of pCO2 (415 ppmv to 20,000 ppmv) and aging time (7 days to 1 month) on hydroxyapatite formation were investigated using experimental geochemistry and X-ray diffraction (XRD) analysis. X-ray diffraction (XRD) analyses showed a decrease in the quantity of hydroxyapatite with increasing pCO2. This is attributed to decreased calcium (Ca) activity and an increase in calcium carbonate formation. Scanning Electron microscopy (SEM) showed rounded particles of hydroxyapatite and zeta potential values of these particles remained positive (2-112 mV) at pH 8 in all samples regardless of pCO2 and aging times. Dissolution experiments showed that higher pCO2 values facilitated the release of P from hydroxyapatite, suggesting the carbonate ligand-promoted dissolution mechanism. Hydroxyapatite was stable at pH 6, but dissolution was enhanced by decreasing pH from 6 to 4. Hydroxyapatite prepared under higher pCO2 released more phosphate than that prepared under pCO2 = 415 ppmv, indirectly suggesting higher solubility in carbonate-substituted hydroxyapatite. The variability of pCO2(g) should be considered to better understand the P cycle in calcareous soils."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Effects of pCO2 on hydroxyapatite formation and its stability: Implications for understanding phosphorus availability in calcareous soil"]}]}],"canonical_facts":{"dc:contributor":["Arai, Yuji"],"dc:creator":["Kalita, Shravani"],"dc:date":["2023-12","2023-11-16"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","The student, Shravani Kalita, accepted the attached license on 2023-11-05 at 12:43.","The student, Shravani Kalita, submitted this Thesis for approval on 2023-11-05 at 17:17.","This Thesis was approved for publication on 2023-11-16 at 16:49.","DSpace SAF Submission Ingestion Package generated from Vireo submission #19367 on 2024-03-01 at 13:29:08","Hydroxyapatite is an important phosphorus (P) sink in calcareous soils. The activity of carbonate in soil pore water, however, is often underestimated because soil respiration and solution-calcite equilibria could elevate pCO2 much greater than 415 ppmv. Thus far, the role of pCO2 in hydroxyapatite formation in calcareous soils has not been extensively investigated. Accordingly, the effects of pCO2 (415 ppmv to 20,000 ppmv) and aging time (7 days to 1 month) on hydroxyapatite formation were investigated using experimental geochemistry and X-ray diffraction (XRD) analysis. X-ray diffraction (XRD) analyses showed a decrease in the quantity of hydroxyapatite with increasing pCO2. This is attributed to decreased calcium (Ca) activity and an increase in calcium carbonate formation. Scanning Electron microscopy (SEM) showed rounded particles of hydroxyapatite and zeta potential values of these particles remained positive (2-112 mV) at pH 8 in all samples regardless of pCO2 and aging times. Dissolution experiments showed that higher pCO2 values facilitated the release of P from hydroxyapatite, suggesting the carbonate ligand-promoted dissolution mechanism. Hydroxyapatite was stable at pH 6, but dissolution was enhanced by decreasing pH from 6 to 4. Hydroxyapatite prepared under higher pCO2 released more phosphate than that prepared under pCO2 = 415 ppmv, indirectly suggesting higher solubility in carbonate-substituted hydroxyapatite. The variability of pCO2(g) should be considered to better understand the P cycle in calcareous soils."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/122084"],"dc:language":["en","eng"],"dc:rights":["Copyright 2023 Shravani Kalita"],"dc:subject":["Hydroxyapatite","Calcareous Soils","Partial Pressure Of Carbon Dioxide","Carbonate Activity","Phosphorus Cycle"],"dc:title":["Effects of pCO2 on hydroxyapatite formation and its stability: Implications for understanding phosphorus availability in calcareous soil"],"dc:type":["text"],"thesis:degree_discipline":["Natural Res & Env Sciences"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:00Z"}