碩士 / 嘉南藥理科技大學 / 環境工程與科學系碩士班 / 95 / In this study, the feasibility of removing chromium (VI) which is a major pollutant from the electroplating wastewater, by nano scale zero valent irons (NZVI) in sequential batch reactors assisted with electric magnetic field was evaluated. Firstly, the nano-scale zero valent irons was prepared through chemical reduction method in the laboratory. It was found that the particle size of nano-scale zero valent iron was in the range of 50 and 100 nm. and the surface area of NZVI was 80 ± 5 m2/g.
This study investigated the effect of solution pH (initial pH 3、pH 5 and constant pH at 3), Fe0：Cr6+ mass ratio ( Fe0：Cr6+ = 10：1、20：1 and 40：1), initial chromium(VI) concentration ( 20 and 50 mg/L), and different kinds of aeration gases on the removal of chromium(VI) and NZVI capability for chromium(VI) removal( g-Cr6+/g-Fe0 ). In the reduction reaction, the solution pH, ORP, DO, Fe2+ ions, total iron, total Cr were also monitored or analyzed.
The results showed that the removals of aqueous chromium (VI) reduced by NZVI using initial Cr6+ concentration at 20 mg/l, initial pH at 3, carbon-dioxide as aeration gas with Fe0：Cr6+ mass ratio from 10：1、20：1 and 40：1 were 39.2, 63.1 and 87.9%, respectively, after 5 batches process. By using Fe0：Cr6+ mass ratio 20：1 at different initial Cr6+ concentration (20, 50 mg/l) in 5 batch runs, the removals of Cr6+ were both 100% in first run. The following run from 2 to 5 resulted in decreasing of removal efficiency.The solution pH plays a important role on the removal of Cr6+. At initial pH 3 and pH 5, the removals of Cr6+ were almost the same ( 74.2 and 73.1% ). However, when solution pH was controlled at constant pH 3 a higher removal of Cr6+ ( 91.9 % )was observed. The removal of Cr6+ using air as aeration gas was found to be 40.7 mg which was larger than that using CO2 as aeration gas ( 31.5 mg ).
| Identifer | oai:union.ndltd.org:TW/095CNUP5515035 |
| Date | January 2007 |
| Creators | Development of, 顏豪成 |
| Contributors | Chin-Hsiang Liao, 廖志祥 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 122 |
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