Zakar White - Virginia Polytechnic Institute and State University
Nanosized titanium dioxide (TiO2) is frequently found in cosmetics, food products, coatings, and other consumer products due to its exceptional stability and low toxicity. This nanomaterial is also a very effective photocatalyst which can be used for the degradation of various water contaminants. However, the potential release of TiO2 nanoparticles into the environment may cause unwanted exposure to humans and ecosystems. Uncertainty exists with regard to the human health and environmental risks associated with TiO2 photocatalytic activity. The present study seeks to evaluate the photocatalytic activity of different TiO2 nanoparticles using high-throughput analytical techniques. I examined the photocatalytic activity of various grades of TiO2 nanoparticles (food-grade, P20, P90, NIST SRM-1898, and Ag-coated P90) with two photosensitive organic compounds : methylene blue (MB), an indicator dye; and nicotinamide adenine dinucleotide (NADH), a biological coenzyme. I employed a high throughput technique of multiwall plate analysis to observe the degradation of the organic compounds under UV illumination. This technique involves the use of a UV transilluminator (310 nm), a UV/Vis spectrometer (650 nm), and a fluorescence microplate reader (excitation wavelength 240 nm, emission detection wavelength 460 nm) to quantify the disappearance of compounds as a function of time. The assumption of Langumir-Hinshelwood’s first order reaction rate was made for MB while a zero-order reaction rate was made for NADH. The results obtained by this experiment indicates similar trends among different TiO2 nanoparticles, different rate of reactions, and techniques similarities between MB and NADH. Future research involves further understanding of NADH photolysis and employing other techniques to examine relations with other organic compounds.
References: Lu, Max. Photocatalysis and water purification: from fundamentals to recent applications. Ed. Pierre Pichat. John Wiley & Sons, 2013: 1-45.
Huang, Xiaohua, et al. “Gold nanoparticles: Catalyst for the oxidation of NADH to NAD+.” Journal of Photochemistry and Photobiology B: Biology 81.2 (2005): 76-83.
Lee, No Ah, et al. “Development of multiplexed analysis for the photocatalytic activities of nanoparticles in aqueous suspension.” Photochemical & Photobiological Sciences 10.12 (2011): 1979-1982.
Funder Acknowledgement(s): National Science Foundation, Nano-Enabled Water Treatment
Faculty Advisor: Yuqiang Bi, firstname.lastname@example.org
Role: I prepared the solution, performed the tests with NADH and Methylene Blue,and analyzed the data obtained from the experiment.