규조토를 사용한 다공성 세라믹 소결과 VOCs 제거 필터 개발

Abstract

Volatile organic compounds (VOCs) contribute to the formation of ozone and have seriously threatened human health. Although many studies have been conducted to remove volatile organic compounds, the study on low-cost diatomite filter for VOCs removal is still limited. Therefore, in this study, a cost-efficient ceramic diatomite filter was developed for VOCs adsorption in a confined space. The density of the diatomite monolith was proportional to the molding pressure, amount of binder, and sintering temperature. The compressive strength was proportional to the sintering temperature and inversely proportional to the amount of binder. Compressive strength was proportional to molding pressure when sintered at low temperature, but inversely proportional to molding pressure at high sintering temperature. This is possible because the diatomite monolith was sintered densely so that the number and size of pores decreased. Considering the porosity and compressive strength, the optimum manufacturing conditions for ceramic diatomite filter are a PEG concentration of 18.6 wt.%, a molding pressure of 2 MPa, and a sintering temperature of 1100 ℃. Adsorption experiments of four toxic gases (TMA, CH3COOH, NH3, and H2S) were carried out using the prepared diatomite ceramic filter in an enclosed chamber under a humidity of 60% and 20 ℃. The initial concentration is 200 ppm and the concentrations of all toxic gases were close to 0 ppm within 120 minutes, which indicates that diatomite ceramic filter had a good adsorption performance on four toxic gases removal. The adsorption isotherm and kinetics models were employed to analyze the adsorption mechanisms. The Langmuir isotherm model was better fit, describing the adsorption of four toxic gases as compared to Freundlich isotherm model. Both pseudo-first order and pseudo-second order fitted in H2S adsorption, while only pseudo-second order was more suitable for adsorption of TMA, CH3COOH and NH3. The current study suggested that diatomite is a promising and cost-efficient adsorbent for toxic pollutant removal in a confined space.