## 3 Results and Discussion
### Effect of the External Environment on \(So_{x}\) Removal Rate  
Figure 9 shows the \(SO_{x}\) removal rate of the textile fibers coated with zeolite after exposure to the external environment. After one washing, the \(SO_{x}\) removal rate dramatically decreased. The decrease was 52.5% at 2% epoxy content. The lowest \(SO_{x}\) removal rate in the textile fibers using deionized water as the dilution solution was 34.9% at the epoxy content of 0%. The removal rate was 77.2% at the epoxy content of 2%, which was 2.2 times higher than that at the epoxy content of 0%. After 10 washings, the \(SO_{x}\) removal rate of the coated textile fibers using deionized water as the dilution solution was 77.6% at 2% epoxy content. In addition, after 10 washings and a single freeze-thaw cycle. The removal rate was 75.5%, which was similar to that before exposure to the external environmental conditions of washing and freeze thawing. Meanwhile, the \(SO_{x}\) removal rate of the coated textile fibers using isopropyl alcohol as the dilution solution after one washing exhibited similar trends to the removal rate using deionized water as the dilution solution. After one washing, the \(SO_{x}\) removal rate of the coated textile fibers using isopropyl alcohol as the dilution solution was 26.6% at the epoxy content of 0%, and 62.4% at the epoxy content of 2%. This implies that a higher epoxy content is effective in maintaining a stable \(SO_{x}\) removal rate in external environmental conditions such as washing or freeze thawing, because the epoxy directly affected the degree of adhesion between the textile fabrics and the zeolite.  
Figure 10 shows the SEM image and EDS spectra of the textile fabrics coated with zeolite. As shown in Figure 10a, before washing, O and Ca, which were the main components of zeolite, were present in the coated fabric in the proportions of 36.7% and 18.1%, respectively. After 10 washings and one freeze-thaw cycle, the proportions of O and Ca were 38.5% and 5.8%, respectively. This implies that the zeolite was well attached to the surface of the textile fabrics after exposure to external environmental condition such as washing or freeze thawing. The attachment of the zeolite to the fabrics was also confirmed in the SEM image in Figure 10b.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Specimens** & \begin{tabular}{c} **Porous** \\ **Material Type** \\ \end{tabular} & \begin{tabular}{c} **Dilution** \\ **Solution Type** \\ \end{tabular} & \begin{tabular}{c} **Epoxy** \\ **Contents (\%)** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Washings** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Freezing-Thaw Cycles** \\ \end{tabular} & \begin{tabular}{c} **Removal Rate (\%)** \\ **SO\({}_{x}\)** \\ \end{tabular} \\ \hline \begin{tabular}{c} Z-IC \\ (Control) \\  Z-A-0-1 \\ Z-A-1-1 \\ Z-A-2-0 \\ Z-A-2-1 \\ Z-DA-1-1 \\ Z-DA-2-0 \\ Z-DA-2-0 \\ Z-DA-2-1 \\ Z-DA-2-0 \\ Z-DA-2-1 \\ Z-DA-2-1 \\ Z-DA-2-1 \\ Z-DA-2-1 \\ Z-DA-2-2-0 \\ Z-DA-2-2-1 \\ C-D-C \\ (Control) \\ C-D-2-1 \\ C-D-2-10 \\ C-D-2-10-F \\ \end{tabular} & \
\begin{tabular}{c} 90\% deionized \\ water and 10\% \\ isopropyl \\ alcohol \\ alcohol \\ \end{tabular} &
\begin{tabular}{c} 0 \\ 0 \\ 1