Study on Surface Treatment of Filter by Nano Structure of ZnO
Date Issued
2010
Date
2010
Author(s)
Lin, Chien-Yu
Abstract
Nano ZnO is one of common used photocatalyst so that there are many manufacturing methods developed in material science and industrial field. In this study, chemical vapor deposition and sol-gel methods were applied to produce different types of nano structure of ZnO to investigate the effect of different factors with the structure characteristics of ZnO, such as growth temperature, flow rate of carrier gas, flow rate of oxygen gas, sintering temperature, concentration of coating solution and sintering time. These surface treatment techniques were applied on stainless steel meshes to manufacture photocatalyst gas filters coated with nano structure of ZnO. A series of UV/ZnO experiments applying these photocatalyst gas filters were executed to evaluate the decomposing capability to acetone and disinfection ability to E. coli. The influence of operating factors on the treatment efficiencies and the optimum operating parameters were also investigated.
According to the results of chemical vapor deposition method in this study, the hexagonal-shaped ZnO crystal will form under the condition of N2/O2 ratio 6：1, growth temperature 600℃, and whiskers will form under the N2/O2 ratio 3：1, growth temperature 800℃. By sol-gel method, circular-shaped ZnO can be grown under the initial Zinc Acetate dihydrate concentration 0.45 M, sintering temperature 700℃, sintering time one hour. The photocatalyst decomposition efficiency of acetone was elevated with lower flow rate and lower initial concentration of acetone by both these two kinds of nano structure of ZnO. The higher BET surface area of circular-shaped ZnO than that of hexagonal-shaped ZnO can be explained to higher overall efficiency of circular-shaped ZnO.Results in disinfection effects to E.coli showed that lower flow rate can obtain more ascended efficiency for both type of ZnO. But disinfection efficiency of hexagonal-shaped ZnO is better than circular-shaped ZnO because of more electron-hole pairs formed from hexagonal-shaped ZnO than circular-shaped ZnO.
Subjects
chemical vapor deposition
sol-gel
UV/ZnO
acetone
E. coli
Type
thesis
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