(217ei) Controlled Release Inorganic Gel for Air and Surface Disinfections

Sim, V., The Hong Kong University of Science and Technology
Budihardjo, F. F., The Hong Kong University of Science and Technology
Han, W., The Hong Kong University of Science and Technology
Ching, W. K., The Hong Kong University of Science and Technology
Chan, C. K., The Hong Kong University of Science and Technology
Yeung, K. L., The Hong Kong University of Science and Technology

Indoor air quality is an important matter of concern within the closed residential and office environment. The recent low ventilated building structure, which reduces running cost of buildings by saving energy, is adversely subject to high build ups of air contaminants. Microbial contaminants are one of the key substances to improve indoor air quality because they can be pathogenic or cause an allergic reaction following inhalation. Additionally, contaminated surface by human activities is a main transmission route for infectious diseases. With regards to this, air disinfection technologies have been strongly driven to develop a brilliant solution for the improvement of indoor air quality. Conventional chemical disinfectants include vaporizing and spraying. However, these biocides have difficulty decomposing, resulting in harmful chemical residues that are hazardous to human health. High Efficiency Particulate Air (HEPA) filter can also be employed to remove bioaerosols but HEPA does not cover the virus scale of micro-organism as well as microbes captured by filters. In a recent research, Ozone technologies were introduced to disinfect air since ozone has a superior property to kill microorganisms without leaving any harmful by-products, but conversely, it is too powerful a disinfectant and an oxidizer to deal with. Ozone treatments, without appropriate measures like deozonation, pose a danger to human health.

In the research, essential oils extracted from natural plants, were employed as disinfection materials since their bactericidal characteristics are well established. A new alcogel containing essential oil for air and surface disinfection was developed using a two step sol-gel process. Prior to the preparation of inorganic alcogels, potent essential oils were selected. The selected oils were then impregnated into inorganic gel network which enables the gel to have a controlled release of the essential oils. The anti-microorganism activities of the gels were examined and their accelerated release rates were compared to commercial organic gels. Furthermore, long-term performances were also investigated to elucidate the controlled release property of the gels. In conclusion, long-lasting effective gas disinfectants with natural essential oils released in a controlled manner from inorganic gels were successfully developed and they were demonstrated to possess efficient anti-microbial properties. The new inorganic gel with essential oils therefore sheds a light on a new application field for air and surface disinfection.