| Summary: | 碩士 === 弘光科技大學 === 環境工程研究所 === 104 === Abstract
The purposes of this study were to examine the effect of UV/TiO2 photocatalysis on the treatment of four specific dyes waste liquid. The effects of photodegradation were compared in the system with TiO2 and without TiO2. In addition to test the optimal TiO2 amount in the system, the effect of centrifugation and the existence of dye on the influence of turbidity were also examined. The characteristic of dyes, such as wavelength, pH, COD, TOC, and turbidity, were analyzed. Four specific dyes - DO297, DO257, DO318, and AO215 were test in this study. These dyes were supplied by a textile company in central Taiwan. The UV spectrophotometer was used to quantify the concentration of dyes. The results were used to evaluate the efficiency of UV degradation technique on the treatment of specific dye waste liquid.
The pH values of DO297, DO257, DO318, and AO215 were showed slight acid to neutral. There was a linear relationship between dye concentration and its COD value. No matter what dye, the COD value was very closely at the same concentration. At the same concentration, the order of TOC values was: DO297 > DO257 > AO215 > DO318.
The characteristic curves of DO297, DO257, DO318, and AO215 dyes were 478nm, 550nm, 412nm, and 574nm, respectively. Four different dyes had different types of calibration curves. The calibration curves of DO297 and DO318 were linear, DO257 was quadratic polynomial, and AO215 was also linear under lower concentration (<10mg/L).
The results of photo degradation showed that DO297, DO257, DO318, and AO215 dyes could be photodegraded with 254-nm of UV light, which even TiO2 was not existed in the system. In the system with TiO2, photocatalysis enhanced the degradation of DO297, DO257, and AO215.
In water samples, the existence of TiO2 influenced the measurement of UV reading of dyes. The higher the TiO2 content, the obstruct effect is more obvious. The UV readings were low. In water samples, the influence of TiO2 to the turbidity of water samples showed linear correation. In other words, the higher the TiO2 content, the measurement of turbidity was also higher. High-speed centrifugation could reduce the high TiO2 content-induced turbidity efficiently. However, centrifugation had negative effect on the reduction of the low TiO2 content-induced turbidity. The existence of dye influenced the measurement of turbidity. The influence of dye was light for high TiO2 content-induced turbidity. However, the influence of dye was great for low TiO2 content-induced turbidity.
Keywords: photocatalysis, UV/TiO2, dye, turbidity
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