학술논문
활성탄 입경이 카페인 흡착에 미치는 영향 / Effect of size of activated carbon on adsorption of caffeine
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
Korean
Abstract
본 연구에서는 카페인 흡착에 활성탄의 입경(i.e. dp = 0.925, 0.513, 0.275 그리고 0.0825 mm)이 미치는 영향을 연구하였다. 활성탄을 이용한 카페인의 등온흡착 실험 결과는 Freundlich 모델보다 Langmuir 모델에 더 적합함을 나타내었다. 흡착 동력학 실험 결과, 유사 1차 반응 속도 모델 보다 유사 2차 반응 속도 모델에 의해 더 잘 모사되었다. 뿐만 아니라 가장 빠른 유사 2차 속도상수는 입경이 0.0825 mm일 때 33.9 g mg-1로 나타났다. 카페인의 흡착 속도는 활성탄 입경이 감소함에 따라 증가하였으며 이는 활성탄 입경이 감소함에 따라 비표면적이 증가하는 BET(Brunauer, Emmett and Teller) 분석결과로 설명할 수 있다. 내부 확산 모델 분석 결과, 카페인의 흡착 속도는 구간 Ⅰ에서는 주로 외부 표면 확산이 발생하고 입경이 감소할수록 흡착 속도가 빠르게 나타났으며, 구간 Ⅱ에서는 활성탄 공극 내부로의 확산이 발생하고 입경이 증가할수록 흡착 속도가 빠르게 나타났다. 또한 열역학적 실험으로부터 카페인의 활성탄 흡착은 활성탄 입경에 관계없이 발열 반응이며 자발적으로 이루어진다는 것을 확인하였다.
Effects of granular activated carbon with various particle sizes (i.e. dp = 0.925, 0.513, 0.275 and 0.0825 mm) on caffeine adsorption were investigated. Adsorption isotherm test indicated that the experimental data is fit well with Langmuir model rather than Freundlich model. The kinetic study showed that the pseudo-second order model was described more accurately than the pseudo-first order model. The fastest rate constant (k2) was 33.9 g mg-1 h-1 when dp was 0.0825 mm. Moreover, caffeine adsorption rates were increased with the decreasing dp, and this could be explained by BET(Brunauer, Emmett and Teller) analysis, which indicated that the surface areas were increased with the decreasing dp. The analysis of intra-particle diffusion revealed that the adsorption rates were more faster with the smaller particles in the phase 1 (i.e. mainly external diffusion), and they were faster with the larger particles in the phase 2 (i.e. intra-particle diffusion). In addition, thermodynamic indicators from caffeine adsorptions on granular activated carbon with various particle size were constant, and they indicated that the reactions was exothermic and spontaneous.
Effects of granular activated carbon with various particle sizes (i.e. dp = 0.925, 0.513, 0.275 and 0.0825 mm) on caffeine adsorption were investigated. Adsorption isotherm test indicated that the experimental data is fit well with Langmuir model rather than Freundlich model. The kinetic study showed that the pseudo-second order model was described more accurately than the pseudo-first order model. The fastest rate constant (k2) was 33.9 g mg-1 h-1 when dp was 0.0825 mm. Moreover, caffeine adsorption rates were increased with the decreasing dp, and this could be explained by BET(Brunauer, Emmett and Teller) analysis, which indicated that the surface areas were increased with the decreasing dp. The analysis of intra-particle diffusion revealed that the adsorption rates were more faster with the smaller particles in the phase 1 (i.e. mainly external diffusion), and they were faster with the larger particles in the phase 2 (i.e. intra-particle diffusion). In addition, thermodynamic indicators from caffeine adsorptions on granular activated carbon with various particle size were constant, and they indicated that the reactions was exothermic and spontaneous.