Sorption and Desorption of 17a-ethinylestradiol (EE2) and b-estradiol (E2) Onto Montmorillonite Clay and Nylon Microparticles
Title: Sorption and Desorption of 17a-ethinylestradiol (EE2) and b-estradiol (E2) Onto Montmorillonite Clay and Nylon Microparticles by Christian Manuelli
Advisor: Dr. Shuowei Cai, Research Advisor, Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth
Committee members:
- Dr. Catherine Neto, Committee Member, Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth
- Dr. Chen-Lu Yang, Committee Member, Environmental Health & Safety Technician, University of Massachusetts Dartmouth
Abstract:
There is growing concern of the adverse effects of endocrine disrupting chemicals (EDCs) on the environment, wildlife, and human beings. EDCs, which consist of poly-chlorinated biphenyls, perfluoroalkyl substances, hormones, among others, enter the environment in multiple ways and have been linked to a wide variety of adverse health effects. One synthetic estrogen hormone used in contraceptives, 17a-ethinylestradiol (EE2), is of particular concern due to high estrogenic activity and high environmental stability. To better understand the transportation and fate of EDCs in the environment and investigate better sorbents for more efficient removal, it’s important to study the solid-liquid interactions of these compounds with common substrates. In this study, the sorption and desorption of estrogens EE2 and its natural counterpart b-estradiol (E2) to montmorillonite clay, a major mineral component in surface aquifers, and nylon microparticles, a common plastic pollutant, was investigated in aqueous solutions. To further study the degradation of estrogens in mixed aqueous environments, the photodegradation of EE2 and E2 in the presence of montmorillonite clay was also investigated. The effect of pH, salinity, and background ionic strength to sorption and desorption was also studied. A novel methodology using fluorescence detection was developed and used as a more efficient alternative to chromatographic determination. Equilibrium between the aqueous phase and clay concentrations was reached after 72 hours, compared to 24 hours with nylon concentrations. The adsorption capacity for nylon microparticles was higher for both estrogens than for montmorillonite, with EE2 displaying stronger interactions to both. Four different models were fitted to the sorption kinetics of both estrogens. Sorption of estrogens to montmorillonite fit only the Freundlich isotherm, while sorption to nylon fit both the Langmuir and Freundlich models well, with R2 values both over 0.95. The proposed mechanism for sorption to nylon was hydrophobic interactions, while mixed effects influenced sorption to montmorillonite clay. Desorption of E2 from clay was slightly stronger than EE2, while desorption from nylon was insignificant for both estrogens after 24 hours. The photodegradation of both estrogens was not significantly affected by the presence of montmorillonite clay.
Event will be held in person and by Zoom
Zoom Meeting ID: 942 7655 3890
Passcode: 181855
SENG 311
Heather Blaser
508-999-8587
Hblaser@umassd.edu
https://umassd.zoom.us/j/94276553890?pwd=S2wW3Tmb0nbxyYRGYywIPxGzaIK07A.1