- Professor Seung Hwan Ko's research team at Seoul National University has developed a novel filter system utilizing water for comprehensive indoor air purification. Unlike conventional air purifiers, which require periodic filter replacement or cleaning, this innovative system employs microbubbles as an alternative to traditional filters, effectively removing both particulate matter (PM) and molecular pollutants, such as volatile organic compounds (VOCs), from indoor environments.

- With growing awareness around indoor air quality due to factors like fine dust and respiratory disease triggers such as COVID-19, there is an increased interest in air quality for prolonged indoor environments, such as vehicles, homes, and offices. Enclosed indoor spaces often suffer from oxygen (O₂) depletion and carbon dioxide (CO₂) accumulation, further exacerbated by pollutants like PM and VOCs, which compound air quality issues.

- Although ventilation by opening windows is effective, it poses risks due to external pollutants entering from the outside, highlighting the need for advanced purification methods. Current air purification systems rely on filter-based systems, facing challenges such as performance degradation from PM accumulation, difficulty in removing molecular pollutants like VOCs, and waste from disposable filters. This underscores the need for eco-friendly air purification technologies.

- Inspired by human respiratory and circulatory gas exchange, the research team developed a comprehensive air purification system designed to remove PM and expel accumulated CO₂ while replenishing deficient O₂ in enclosed spaces.

- In the human respiratory and circulatory systems, the lungs and peripheral blood vessels perform gas exchange, releasing CO₂ and supplying O₂, while blocking external particulate matter. This process enables gas exchange without direct exposure to the outdoor environment and removes waste through renal circulation.

- Drawing inspiration from these efficient physiological mechanisms, the research team proposed a new recirculating air purification system that integrates a microbubble-based gas exchange mechanism with a water circulation system, similar to alveoli, capillaries, and blood flow.

- By leveraging the dissolution of particulates and gas molecules (including O₂ and CO₂) at the water-air interface of microbubbles, a gas exchange device was implemented. The team achieved stable, small microbubble formation by utilizing elastomeric microporous filters created through laser processing. By circulating water with dissolved gases, the system balances the gas composition between two spaces, ensuring continuous CO₂ emission from enclosed spaces. This process demonstrated the system’s sustainable operation without requiring stoppage or replacement, thanks to its self-purifying function.

- Furthermore, the simple operating principle allows scalability, enabling the system to connect multiple indoor and outdoor environments, forming a network capable of building-level air purification, potentially replacing conventional HVAC systems.

- Professor Seung Hwan Ko said, “This environmentally friendly technology, which replaces traditional filters with a simple water-based mechanism, purifies both particulate and molecular pollutants without generating filter waste, providing a sustainable alternative to existing filtration systems.”

Concept and actual configuration of an air purification system inspired by the human circulatory and respiratory systems

[Reference] 

Jeong, Seongmin, et al., (2024) “Human Circulatory/Respiratory-Inspired Comprehensive Air Purification System”, Advanced Materials (2024), https://doi.org/10.1002/adma.202405568.

[Main Author] 

Seongmin Jeong (Seoul National University, SNU)

Jaeho Shin (Korea Institute of Science and Technology, KIST)

Jinmo Kim (Seoul National University, SNU)

Sukjoon Hong (Hanyang University)

Seung Hwan Ko (Seoul National University, SNU)

* Contact : Professor, Seung Hwan Ko (maxko@snu.ac.kr)