Discipline: Chemistry and Chemical Sciences
Subcategory: Pollution/Toxic Substances/Waste
Room: Exhibit Hall
Kyla Smith - Lawson State Community College
Co-Author(s): Sarah Nealy, Daniel Inman, Veronika Kozlovskaya, Eugenia Kharlampieva, University of Alabama at Birmingham, Birmingham, Al
In this study, photocatalytic nanocomposites composed of a poly-(D,L- lactic acid) (PLA) polymer matrix with integrated titanium dioxide (TiO2, titania) were synthesized for UV-triggered degradation of organic contaminants in polluted water. PLA is a hydrophobic polyester that is tunably degradable, cost-effective, and biocompatible. Among the nanofillers employed, titania has emerged as the prevailing one as it is inexpensive, nontoxic, and highly stable with interesting defect chemistry. This research aims to demonstrate the fundamental relationship between matrix porosity and morphology on photoactivity and degradability of PLA/TiO2 microparticles. Fabrication of the microparticles was performed in an oil/water emulsion under mild synthetic conditions, which provided relatively monodisperse samples with average particles being ~20-40 mm in size. The concentration of the porogen, 2-methylpentane (2-MP), varied between 0-40 wt% to study the effects of porosity on microparticle size, morphology, and photocatalytic activity. It was hypothesized that the presence of 2-MP would impact the rate of microparticle degradation and photoactivity as porosity determines the available surface area on the microparticle for interactions with the model organic contaminant, rhodamine 6G (R6G) dye. The removal of R6G dye from aqueous solution by the PLA/TiO2 microparticles was achieved in the presence of UV light and quantified by UV/visible spectroscopy. We have demonstrated that the sorption capacity, dye degradability, and composite disintegration can be selectively tuned by controlling the microparticle porosity and distribution of incorporated titania nanoparticles. In addition to offering new approaches for environmental remediation, this study offers insight into the interactions at the PLA/TiO2 interface, providing an opportunity to advance strategies for synthesis of novel polymeric nanocomposites.
Funder Acknowledgement(s): Support was provided by National Science Foundation (Grant Number DMR # DMR 1754078)- Research Experiences for Undeergraduates (REU) award to UAB.
Faculty Advisor: Eugenia Kharlampieva, firstname.lastname@example.org
Role: The primary contribution, I made to the research consisted of handling solvents and solutes, including Ethanol, Polylactic acid (PLA), Titanium Tetraisopropoxide (TTIP), Polyvinyl Acetate (PVA), Dichloromethane, and 2-methyl pentane (2MP). With these chemicals, preparation of precursors and samples were made. Techniques including: Vortexing (shake for uniform distribution), was necessary for proper observation, which was completed by preparing samples to go under optical microscopy. Identification of a rough surface area, and particle enlargement was presented due to the increase of porogen that included in each sample. The progression continued, by using the samples and joining R6G dye to prepare for exposure to UV light and, withstand photodegradation. The UV light exposure to the samples, consisted of a 2-4 hr. period. Removal of the R6G dye was visible, which then concluded that contaminant removal is possible if there is an increase of porogenic material.