Research
Plastic recycling
Plastics have greatly enriched human life. Yet, because of their high utility and biological stability, 300 million tons of plastics are discarded every year, threatening the survival of humanity.
Our lab focuses on synthesizing nanocatalysts with various compositions, sizes, and shapes, applying them to plastic depolymerization. Through this, we seek to optimize depolymerization conditions for PET and other polymers. By minimizing the thermal energy and separation steps needed for polymer depolymerization, we aim to cut down the cost of chemically recycled polymers. Additionally, we are developing efficient pretreatment technologies, including magnetic nanocatalyst-mediated dye removal and the separation of blended fibers.
1. Nanoparticle Synthesis
Design of functional nanoparticles through controlled composition, size, and surface chemistry
Precise control of nanoparticle structure is essential for developing efficient catalytic and purification systems. Our lab synthesizes uniform metal oxide nanoparticles, such as ZnFe₂O₄ and Fe₃O₄, using heat-up and thermal decomposition methods. By tuning the particle composition, crystal structure, and surface ligands, we control their dispersibility, catalytic activity, adsorption behavior, and magnetic recovery. These nanoparticle platforms are used to study how nanoscale structure affects chemical recycling and separation processes.
Kim et al. ACS Sustain. Chem. Eng. published
H. Hwang et al., Nanoscale, 17, 2025
2. Chemical Recycling
Development of catalytic systems for converting PET waste into reusable monomers
Chemical recycling is a promising strategy for converting PET waste into high-value monomers without degrading material quality. Our lab develops ZnFe₂O₄@citrate inorganic/organic hybrid magnetic nanocatalysts for PET glycolysis. In this system, Lewis acid sites on the ZnFe₂O₄ surface and Lewis base sites from citrate ligands cooperatively promote the depolymerization of PET into BHET. This catalyst enables PET glycolysis under relatively mild conditions and can be easily recovered using an external magnet, supporting an energy-efficient closed-loop recycling process.
Kim et al. ACS Sustain. Chem. Eng. published
3. Pre- and Post-Treatment
Development of treatment processes for high-quality textile and plastic recycling
Real waste recycling requires additional treatment steps because textile waste often contains blended fibers, dyes, and other impurities. Our lab develops NMMO-based pretreatment to selectively dissolve cotton components from PET/cotton blended textiles while preserving the structure and mechanical properties of PET fibers. After depolymerization, ligand-controlled Fe₃O₄ magnetic nanoadsorbents are used to remove residual disperse dyes from recycled monomer solutions. These pre- and post-treatment strategies help improve monomer purity and enable high-quality recycling of colored or blended polyester waste.
H. Hwang et al., Nanoscale, 17, 2025
S. Lee et al., Text. Sci. Eng., 63, 2026