Harmful algal blooms (HABs) pose significant threats to industries such as fisheries and tourism and also impact public health through the production of cyanobacterial toxins. To address the escalating concerns associated with HABs, we have developed novel calcium alginate hydrogel composites seeded with various minerals to effectively remove and recover phosphorus (P) and nitrogen (N). In this talk, I will present three distinct mineral–hydrogel composites designed to tackle nutrient-enriched wastewater, particularly from municipal sources. First, calcium alginate (Ca-Alg) combined with calcium phosphate (CaP) effectively captures P. Second, composites incorporating both CaP and calcium silicate-based mineral seeds (Ca-Alg/CaP+Wollastonite (CaSiO3)) show enhanced P removal and recovery even under low saturation conditions. Third, composites seeded with nanoscale struvite minerals (Ca-Alg /CaP+Struvite (NH4MgPO4·6H2O)) simultaneously mitigate P and N (ammonia) levels in water. The inclusion of nanoscale mineral seeds reduces the nucleation energy barrier and promotes heterogeneous nucleation, leading to increased mineral formation and nutrient recovery. The hydrogel matrix creates locally higher saturation conditions for CaP and struvite, enabling nucleation even under undersaturated bulk water conditions. These innovative mineral-hydrogel composites offer sustainable nutrient cycling by concurrently removing NH4+ and phosphate from waste to maintain safer nutrient concentrations in aquatic systems. Furthermore, they provide exciting opportunities to upcycle the high-purity heterogeneously formed struvite and CaP as valuable resources for plant and algae growth.
Speaker Bio:
Dr. Young-Shin Jun is a Professor of Energy, Environmental & Chemical Engineering at Washington University. She received her bachelor’s and master’s degrees from Ewha Womans University, holds master’s and PhD degrees at Harvard University, and conducted postdoctoral research at the University of California-Berkeley/Lawrence Berkeley National Laboratory. Dr. Jun advances the understanding of nanoscale interfacial chemistry and solid nucleation to tackle key challenges in energy and the environment. She currently focuses on three critical areas: CO2 chemical systems for clean energy; novel technologies to recover critical elements, nutrients and valuable salts from unconventional resources; and nanomaterials synthesis and nanotechnologies for improving the quality of water and soil. Professor Jun has received numerous awards, including the 2008 Ralph E. Powe Junior Faculty Award, the 2011 U.S. NSF CAREER award, the 2020 James Lee Award, the 2022 Jackson Award, a 2022 AEESP Distinguished Service Award, and an IUPAC 2025 Distinguished Women in Chemistry or Chemical Engineering Award. She was named a 2015 Kavli Fellow by the U.S. National Academy of Sciences, a 2016 Frontier of Engineering Fellow by the U.S. National Academy of Engineering, a 2018 Fellow of the Royal Society of Chemistry, a 2019 Fellow of the American Chemical Society (ACS), and a 2024 Fellow of the American Association for the Advancement of Science (AAAS). Dr. Jun is an Editorial Board Member of ACS ES&T: Engineering, RSC Advances, and Current Opinion in Chemical Engineering.