Bomb Calorimetry: A New Method of CEC Determination

A new method of determining the cation exchange capacity (CEC) of clay minerals was examined. This method involved exchanging the smectite clay with organic cations and using bomb calorimetry to measure the energy of combustion of the material. Because the clay is noncombustible, the energy is completely dependent on the amount of organic present, which is dependent on the CEC of the clay. Two organic cations, tetrapentylammonium and octadecyltrimethylammonium , with similar size but much different shape were used. For clays with lower CECs, using the more symmetric ion yielded better accuracy (4.24%), while for clays with higher CEC, using the straight chain organic yielded better accuracy (1.16%). Overall, the results indicate that using bomb calorimetry presents a viable option in the determination of cation exchange capacity

Longitudinal Study of Lanana Creek

A longitudinal study was done to collect data on the various conditions of LananaCreek in Nacogdoches, Texas over a seven week span from September 14 to November 2, 2018. The part of the creek studies is a 3.5 mile stretch from East Austin Street to Hoya Soccer Complex, mostly located on the campus of Stephen F. Austin State University. There were 6 different testing sites selected along this expanse. Collection of samples was performed by the General Chemistry I Honors class as part of the laboratory experience. Once collected, the samples were transported back to the lab for testing. The tests performed on the samples included determination of the pH, total solids, total dissolved solids, water hardness, anion concentration, and alkalinity. Each of these tests analyzes for a different parameter that is essential in evaluating the health of the ecosystem as a whole and gives a good reflection of the overall health of the creek’s surrounding environment. The results were compared to EPA standards. During the testing period, there were significant rain events generating variable results after each sampling, but the overall study shows that LananaCreek is healthy