| Summary: | 碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 107 === In this study, titanium dioxide nanotube (TNT) and Ag-modified TNT that were synthesized by adding different weight of AgNO3 were applied to remove arsenite (As3+) and arsenate (As5+) in solution. The results showed that the removal efficiencies of TNT, Ag(5)-TNT, Ag(10)-TNT and Ag(20)-TNT for As5+ (10 ppm) were 79.8%, 90.2%, 94.1%, and 86.8%, respectively. Ag(10)-TNT possessed the best removal efficiency for As5+ which compared with other samples. Moreover, the removal efficiency decreased with increasing pH value. For competitive adsorption experiments, phosphate had greater influence than sulfate for TNT samples on adsorption of arsenic species. The removal efficiency dropped about 30%−40% when added 15 ppm phosphate in solution. All resultant TNT samples can oxidize As3+ when UV irradiation was applied. The resultant samples (40 mg) can oxidize 10 ppm As3+ completely, and remained 3.3−4.7 ppm of As5+ in solution. In order to investigate the oxidized mechanism of TNT sample for As3+, ascorbic acid, fluoride ion, and third butanol were also added. Furthermore, TNT and Ag(10)-TNT were utilized to remove As5+ (1 ppm) in continuous adsorption experiments and the removal efficiency reached 96%. After TNT and Ag(10)-TNT treatment, the groundwater that contain 1 ppm As5+ can nearly meet the standard of 10 ppb.
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