Chemistry Seminar: Microplastics and Atmospheric Aerosols (2 MS Thesis Proposals)

Double Feature of MS Student Thesis Proposals!

Register Here for Zoom Link

Presentation #1:
The Changes of Microplastics caused by Environmental Aging

Mechelle Cureaux
Chemistry MS Candidate
School of Chemistry and Materials Science, RIT

Mechelle will present a thesis proposal talk about microplastics degradation over time in the environment.

Abstract:
Microplastics are known pollutants of aquatic systems causing harm to the surrounding ecosystem and health of living organisms. Microplastics are tiny fragments of the plastics that break down into 5mm or smaller over time by environmental effects. Environmental effects age the larger plastics by degrading their structures with UV lights, winds, wave action, etc. Many plastics have additives to prolong their properties by making them more flexible, UV resistance, and to add color. Dense plastics will sink quickly, and some will sink eventually due to weathering and biofouling. While in an aquatic environment, the chemical additives will leach into the water column. The bottom feeder benthos ingest the microplastics as well as the released additives. These aging effects of microplastics do make an impact on the life cycle of the aquatic organisms, and they die or have health issues. I will study the leaching of additives from six different types of plastic that are being aged in four different locations in and around the city of Rochester. There will be sampled three times over the course of 12 months. I will also conduct a controlled laboratory experiment for analysis of leaching of additives to understand the process. In addition, I will study how aging of plastics in different aquatic environments alters the physical and chemical structure of the polymers.

Speaker Bio:
Mechelle R. Cureaux was born and raised in New Orleans, Louisiana. She graduated from Loyola University New Orleans in 2015 with a Bachelor degree of Science in Chemistry on Forensic Science track . She was the first intern for the coroner’s office and assisted with 13 autopsies. She has worked at a toxicology lab as DOT certificated Lab Technician II for over 2 years in the Extraction department . She is currently a first year graduate student in the Chemistry MS Program, and a scholar for Rochester Bridges to the Doctorate Program for a PhD program in Toxicology at UR.

Presentation #2:
Liquid-Liquid Phase Separation of Atmospheric Aerosols and the Effects of Oxygen to Carbon Ratios

Jillian Denison
Chemistry MS Candidate
School of Chemistry and Materials Science, RIT

Jillian will present a thesis proposal talk about the dynamics of partitioning of inorganic acids during liquid-liquid phase separation (LLPS).

Abstract:
Secondary organic aerosols (SOA) are formed in the atmosphere and are a mixture of organic and inorganic compounds. SOAs undergo liquid-liquid phase separation (LLPS) as relative humidity decreases, separating into a core and shell. This happens because of the salting out effects of electrolytes. Current literature shows that LLPS occurs only if the ratio of oxygens to carbons (O:C) of the organics is between ~0.56 and ~0.71. Majority of studies look at systems of one organic and inorganic component, and those which study multiple organic components focus on the average O:C ratio of the system to determine if LLPS occurs. Using optical and Raman microscopy, I am studying how the O:C ratio of individual organic compounds influences where it resides during LLPS of mixed organic systems. We hypothesis that while average O:C ratio will determine if LLPS occurs, the O:C ratio of individual compounds will determine where it will reside during LLPS. In addition, I will be studying the dynamics of partitioning of inorganic acids during LLPS.

Speaker Bio:
Jillian Denison is from Garden City, Michigan. She started at RIT in 2017 and shortly after, began working with Dr. Eddingsaas on the liquid-liquid phase separation project. During the summer of 2018, she had and REU at Washington State University working with biochar to reduce emissions from compost. She was awarded the Emerson Summer Research Fellowship in 2019 to work on the LLPS project. She is set to receive her Bachelor’s in Chemistry in December 2020 and her Master’s in Chemistry in December 2021.

Intended Audience:
Undergraduates, graduates, and experts. Those with interest in the topic.