The Effect of Composition and Structure on the Dissolution Rates in Water of Alkali- Alkaline Earth Borate Glasses
Department
Materials Science and Engineering
Major
Ceramic Engineering
Research Advisor
Brow, Richard K.
Goetschius, Kathryn
Advisor's Department
Materials Science and Engineering
Funding Source
Center for Biomedical Science and Engineering
Abstract
Fifteen different borate glasses with molar compositions 10X2O·10RO·80 B2O3, 15X2O·15CaO·70B2O3, and 20X2O·20CaO·60B2O3 (where X =Li, Na or K and R =Mg, Ca or Sr) were characterized using NMR, FTIR, and Raman spectroscopies. The fractions of boron tetrahedra (B4) were determined; 0.45 of the borate units in glasses with 60 and 70 mole% B2O3 were tetrahedral, compared to 0.29 in glasses with 80 mole% B2O3. The dissolution rate in 37 °C water was determined from glass powders by measuring the boron release rate using ICP-OES. Dissolution rate constants were determined using a contracting volume model for spherical particles. Glasses with 80 mole% B2O3 (fewer B4 units) dissolved about an order of magnitude faster than glasses with more B4 units. Glasses with greater field strength alkali (Li < Na < K) and alkaline earth (Ca < Sr) ions dissolved 25-50% more slowly; Mg-containing glasses did not follow this field strength trend.
Biography
Michaela is a Senior in Ceramic Engineering from the St. Louis, Missouri area. She has been working with Dr. Brow’s glass research group for about a year and a half, and will be graduating in December. She is involved with Keramos (professional Ceramic Engineering fraternity), the Water Environment Federation (WEF), and Lambda Sigma Pi (women’s community service organization).
Research Category
Engineering
Presentation Type
Poster Presentation
Document Type
Poster
Award
Engineering poster session, First place
Location
Upper Atrium/Hall
Presentation Date
16 Apr 2014, 1:00 pm - 3:00 pm
The Effect of Composition and Structure on the Dissolution Rates in Water of Alkali- Alkaline Earth Borate Glasses
Upper Atrium/Hall
Fifteen different borate glasses with molar compositions 10X2O·10RO·80 B2O3, 15X2O·15CaO·70B2O3, and 20X2O·20CaO·60B2O3 (where X =Li, Na or K and R =Mg, Ca or Sr) were characterized using NMR, FTIR, and Raman spectroscopies. The fractions of boron tetrahedra (B4) were determined; 0.45 of the borate units in glasses with 60 and 70 mole% B2O3 were tetrahedral, compared to 0.29 in glasses with 80 mole% B2O3. The dissolution rate in 37 °C water was determined from glass powders by measuring the boron release rate using ICP-OES. Dissolution rate constants were determined using a contracting volume model for spherical particles. Glasses with 80 mole% B2O3 (fewer B4 units) dissolved about an order of magnitude faster than glasses with more B4 units. Glasses with greater field strength alkali (Li < Na < K) and alkaline earth (Ca < Sr) ions dissolved 25-50% more slowly; Mg-containing glasses did not follow this field strength trend.
