Melissa Setz (Georgia) coauthored a paper entitled "Lithium Extraction to Determine Ammonium in the Exchange Complex of Bentonite" that was published in the Geotechnical Testing Journal in Volume 42, Issue 1 on August 16, 2018.
Her coauthors were Craig H. Benson, Sabrina L. Bradshaw, and Kuo Tian.
Melissa is a Geotechnical Engineer based in Georgia focused on characterization and remedial investigations; geotechnical engineering quality control practices; and implementation and compliance. Her professional experience includes a broad range of expertise in geotechnical engineering on projects for commercial, industrial, and federal clients.
The purpose of the Geotechnical Testing Journal is (1) to provide a high-quality publication that informs the profession of new developments in soil and rock testing and related fields; (2) to provide a forum for the exchange of information, particularly that which leads to the development of new test procedures; and (3) to stimulate active participation of the profession in the work of American Society for Testing and Materials (ASTM) International Committee D18 on Soil and Rock and related information.
ASTM D7503, Standard Test Method for Measuring the Exchange Complex and Cation Exchange Capacity of Inorganic Fine-Grained Soils, is used to determine soluble and bound cation concentrations as well as the cation exchange capacity of fine-grained soils used in barrier systems for waste containment, including bentonite in geosynthetic clay liners (GCLs). ASTM D7503 prescribes the use of 1 M ammonium acetate (NH4OAc) as an extraction liquid for bound cations, which masks ammonium (NH4+) that may be in the exchange complex in bentonite in contact with municipal solid waste (MSW) leachate. A 1 M lithium bromide (LiBr) extraction liquid is proposed as an alternative to the 1 M NH4OAc in ASTM D7503 so that NH4+ in the exchange complex can be quantified without interfering with measurement of other bound cations of interest for waste containment. Nearly the same distribution of bound major cations was obtained using the method in ASTM D7503 and the proposed alternative using 1 M LiBr for two bentonites from two new GCLs (not permeated). Using the 1 M LiBr method revealed substantial NH4+ bound to eight bentonites obtained from GCLs that had been permeated with different MSW leachates. The bound NH4+ concentration varied directly with NH4+ concentration in the leachates, and this variance explained a charge imbalance obtained from tests conducted on the bentonites using the standard method in ASTM D7503.
Learn more about the paper at: Lithium Extraction to Determine Ammonium in the Exchange Complex of Bentonite.
Learn more about Melissa at: https://www.linkedin.com/in/missysetz/