Asbestos in various building materials were measured by spectral sensor to examine the shift in reflectance wavelength according to asbestos concentration in different materials. Asbestos glove, asbestos soil, asbestos fiber insulation board, slate and bamlite panel were tested under several experimental conditions to alter reflectance intensity at each wavelength to find the optimum condition to detect asbestos selectively from other particulate matters. Chrysotile was found to have specific wavelength range regardless of concentration and type of materials as detected under blue color filter and dyed with refractive index liquid.

We suggest new approach to monitor indoor air quality by using selective VOCs sensor specialized to detect formaldehyde, benzene, toluene with distinct sensitivity. One of the major drawbacks in semiconductor type gas sensors is poor selectivity despite of high sensitivity in detection of trace level of gases. Graphene oxide was deposited as a sensing layer on silicon dioxide sensor with platinum bottom electrodes. Thermal treatments under varying temperature, time, and gas, were performed to reduce graphene oxide at a certain amount as desired. Depending on the degree of reduced graphene oxide, obvious difference in functional groups in terms of type and number was observed. Following sensing behavior measurements confirmed that partial reduction of graphene oxide determined the selective gas adsorption to influence the sensing behavior to improve the selective VOCs detection for better indoor air quality.

The purposes of this study are to prepare Hanji fiber-filter sheets using replacement liquid in water-swollen fiber with non-polar solvent such as ethanol, methanol and pentane. The experiments were studied on the selection of optimal non-polar solvent and the optimal drying method for wetted fiber and then were to know physicochemical characteristics of prepared Hanji fiber-filter sheet. The Ethanol as liquid changer in water-swollen fiber was excellent solvent and the optimal drying method for them was freeze drying served with vacuum pump. The bulk density and porosity of prepared fiber sheet from freeze dryer were 0.11-0.13 g/mL, half of natural dried fiber sheet, and 90%, respectively. The results of SEM observation for the fiber sheet prepared with natural drying or heating drying were shown very close structure of fiber wall in dry state. However, the freeze drying sheet were shown the open structure. So, the head loss of freeze drying sheet was very lower than natural drying and heating drying sheets. From the results of BTEX removal experiments, the sheets dried at water wetted condition was shown more higher efficiency than the fiber sheets dried at solvent wetted condition.

Graphene oxide (GO) thin films were fabricated into thin film sensor for the selective VOCs detection. Different concentrations of GO aqueous solutions (6.2g/L and 5.0 g/L) were tested and thermally treated to obtain the appropriate sensing layer in terms of specific surface area and functional group. For the selectivity, it was assumed that different numbers and types of attached functional group of GO could induce the difference in gas adsorption, which may consequently derive to the selective VOCs detection. FE-SEM, XRD, and FTIR were utilized to characterize crystalline phase and functional group change by heat treatment condition and resistance measurements were followed. We suggest that thermally treated GO thin film sensor can be the alternative approach to achieve the improved selectivity in multiple gas detection by controlling the degree of gas adsorption.

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