Steric Effects of Alkyl Ammonium Salts on the Combustion of Exchanged Smectite Clays

<p>Bomb calorimetry was explored as a new method for determining the cation exchange capacity (CEC) of clays. Smectite clays were modified with several alkyl ammonium salts varying in number of carbons and the spatial orientation of the carbons about the central nitrogen atom. The clays used, standards purchased from the Source Clay Repository, have CECs of 44, 80, 88, and 120 meq/100 g. Theoretically, the combustion energy of the organo-clays should be approximately the same for each salt. Any differences in energy would be due to the different structures of the salts and how they are oriented in the interlamellar region of the clay. The number of alkyl ammonium salts that bind to the negatively charged sites in the clay layers would represent the CEC of the clay. The orientation of the organic cation in the interlamellar region was examined using x-ray powder diffraction, which provides the spacing between the clay layers. The combustion energy data collected using bomb calorimetry was used to calculate the CEC of the clay by comparing the energy from the pure salts to determine the number of salt molecules intercalated into the clay. Since the pure salt and the clay have a one-to-one charge ratio, the number of salt molecules will directly represent the number of negatively charged sites on the clay which is the CEC of the clay. </p>

Name thesis:degree_name

Master of Science - Natural Sciences

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

College of Science and Mathematics

Year dc:date.available

2018

Author dc:creator

• Keith, Celeste A.

Contributors dc:contributor

• Dr. Alyx Frantzen
• Dr. Russel J. Franks
• Dr. John Gary

• chemistry
• physical chemistry
• smectite clay
• alkyl ammonium
• combustion
• Analytical Chemistry
• Environmental Chemistry
• Inorganic Chemistry
• Organic Chemistry

Repository record dc:identifier

https://scholarworks.sfasu.edu/etds/198

OAI identifier oai:identifier

oai:scholarworks.sfasu.edu:etds-1212