Research Information

Development of Korean Hanji filter
  • ManageDepartment of Land, Water and Environment Research
  • Date2019-11-26
  • Hit0
ㅇ Overview
- Development of high added value new material for removing environmental pollutants by combining state-of-the-art science and technology with traditional Hanji cellulose fiber
- Addressing the social problem of major pollutants such as fine particulate matter and VOCs, and developing environmental material production technologies, thereby gaining a competitive edge over advanced economies

ㅇ Research Contents 
○ Development of Hanji filter and activated charcoal-infused Hanji filter
- Developed technology: Cellulose fiber is dispersed in a solvent by adding non-polar material such as tertiary butyl alcohol to prevent the wind-up phenomenon. Free-drying is used to evaporate the solvent to prepare a porous (porosity: 90%) Hanji filter with layered cellulose fibers. 
   A cation bonding agent is used to evenly and electrostatically bind powdered activated charcoal to the cellulose Hanji fiber, resulting in an activated charcoal-infused Hanji filter from which the powdered activated charcoal does not come loose and which is able to simultaneously remove fine particulate matter and VOCs.
○ Synthesis of porous aluminosilicate zeolite containing a regenerable iron component
- Developed technology: Ammonium iron citrate is chemically bound to an aluminosilicate frame to synthesize porous zeolite containing an iron component that is able to absorb and remove VOCs. VOCs adsorbed by zeolite are radiated with UV light, causing electrons to be released from the iron component within the porous material. This, in turn, causes oxidation (photo-fenton oxidation) of the VOCs. Absorption and oxidation (regeneration) can be carried out on-site, allowing infinite reuse.  

hanji filter
Porous Hanji Filter 

ㅇ Research Achievements
○ Technological value
 - The commercialized fine particulate matter removal technologies currently used worldwide involve electrical dust collection devices that are primarily for industrial use only. Dust filters produced by companies such as Samsung and LG for the removal of fine particulate matter in household environments use discontinuous fiber spinning (melting blown, electro spinning, etc.) technology. This technology is used to coat a non-woven fabric with synthetic fibers; the non-woven fabric is then folded into a metal enclosure through which air can freely pass. A widely used adsorbent for the removal of VOCs is activated charcoal; however, the greatest problem associated with activated charcoal is the high cost of facilities used for regeneration. The technologies currently used cause environmental pollution, and production has been migrated to developing economies such as China and India.
 -  A “porous Hanji filter” and “activated charcoal-infused porous Hanji filter” have been developed as part of this study. This technology, which is unique to Korea, involves the simultaneous removal of fine particulate matter and VOCs using a single flat sheet/filter. “Photo-fenton oxidation” technology using iron-containing zeolite and UV irradiation is a new concept in VOC removal and allows for absorption and filter absorbent regeneration. This newly developed technology is designed to replace many of the preexisting technologies developed by advanced economies.
 - The fine particulate matter (1 um – 10 um) removal efficiency of a single “activated charcoal-infused porous filter” is 99% at 1m/sec flux. Up to 99% BTEX removal is also possible. The “iron-containing zeolite + UV irradiation” technology is able to readily remove pollutants and is easy to regenerate, allowing for semi-permanent use. 

iron-containing zeolite + UV irradiation

○ Scientific value
 - Approximately 16 articles have been published in SCI(E) journals on the Hanji filter and its iron-containing zeolite technology, which serves as further proof of the scientific value of the technology. In particular, an article relating to iron-containing zeolite and UV irradiation was published in J. of Hazardous Materials (I/F:6.5). 
○ Social value
 - In recent times, fine particulate matter, volatile carcinogens, and new house & building syndrome have been keywords in some of the social issues in Korea. 
 - To remove fine particulate matter and VOCs using current technologies, a dual filter combining a non-woven fabric filter and an activated charcoal filter is necessary. However, using the activated charcoal-infused Hanji filter, both fine particulate matter and VOCs can be removed using a single filter. The iron-containing zeolite can be regenerated and reused. 
 - The technology developed through this study is significant in that it uses unique Korean traditional technology to provide a solution to problems experienced by our society, allowing it to replace technologies currently being used by other advanced countries.
○ Economic value (10)
 - The price of indoor dust filters, including non-woven fabric filters and activated charcoal filters, is approximately KRW 200,000 per set, but the price of a Hanji filter is KRW 10,000/filter, approximately 1/10 of conventional filters. Also, whereas activated charcoal filters require housings, no particular housing is required when using iron-containing zeolite. 

ㅇ Expected Effects 
○ Technological value 
 - Development of Korean Hanji filter able to simultaneously remove fine particulate matter and VOCs
 - Development of iron-containing absorbents capable of regeneration, replacing technologies used by advanced economies
○ Social benefits
 - Indoors: Can be used in the manufacture of air conditioner and air purifier filters (for simultaneous removal of fine particulate matter and VOCs)
 - Outdoors: Filters for HVAC system air intakes for public facilities such as schools and department stores