HU JINYUAN

Ph.D. candidate

National University of Singapore

Ms Jinyuan Hu is a Ph.D. candidate in Environmental Engineering at National University of Singapore. She received a master of environmental science from Nanjing University where she focused on investigating the removal of arsenite and atenolol in water. Her work provided new ideas to control inorganic/pharmaceutical contamination and led her to publish two first-authored papers in Environ. Sci. Technol. and Chemosphere. Over the course of 3 years pursuing a Ph.D. degree, she enjoys exploring innovative treatment techniques for microplastics. Her projects including the aging/removal of microplastics by ozonation and UV irradiations funded by collaborative research with University of Toronto and Tokyo University respectively also led her to have one review paper under review in Water Res. and one research paper submitted to Sci. Total Environ. And she takes pride in participating in international conferences and thrives on sharing progress, like presenting in Water and Energy Solutions bilateral workshop. Her work provided a foundation to achieve efficient removal of microplastics. 

Aging/Removal of Microplastics by Ozonation and UV Irradiation

Microplastics (MPs) are ubiquitous in the environment, of which 94% undergo aging processes. Accelerated aging induced by advanced oxidation processes (AOPs) is significant in explaining the formation pathway of secondary MPs and allows mineralization to occur, among which UV irradiation and ozonation are of great significance considering UV and ozone are widely applied in water treatment plants. This study aims to evaluate the feasibility of ozonation (O3, O3/H2O2) and UV irradiation (UV365/H2O2) for the accelerated aging/mineralization of MPs (PE, PVC, and PS) commonly detected in natural water. Emphasis was laid on the alteration of MPs in physiochemical characteristics via multiple technologies including stereo microscope, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Mineralization was defined by simulating the conversion of CO2 through the detection of inorganic carbon (IC) generated in the off-gas. It was confirmed that fragmentation and formation of oxygen-containing functional groups occurred to MPs during photoaging and ozonation, and EEM analysis indicated that photoaging of PS promoted the release of leachate or generation of small molecular organics. Besides, it was suggested that 20 mM H2O2 accelerated the mineralization of PE MPs under ozonation by 1.48 times for facilitating the production of hydroxyl radical (OH•). The mineralization of PVC under ozonation (O3/H2O2) follows a zero-order kinetic model, where the relatively low dechlorination suggests PVC transformation is not bond cleavage with lower energy, but free radical sensitization. These results contribute to understanding the long-term aging behaviors of MPs and provide a foundation to achieve efficient mineralization and further mitigate microplastic pollution.